Tall vs. Short Spindles

Quote:

"I'll post my rebuttal later." Jeez, and I thought you had once said you wouldn't comment on this issue again.

Eh, I got a second wind. I have no problems with the taller spindles provided:

A)The person is completely informed of the difference and is cautioned as to the possible outcome of using the taller pieces before making a decision.
OR
B)The person uses the tubular upper control arms to correct the problem.

Here's the way I look at it. Why take the chance? Maybe 1 out of 1500 have problems with the taller spindles. But you know what, the way my luck is, I'd probably be that 1. This is the safety of you, the safety of your passengers, and the safety of me, John Q. Motorist, who's in the on-coming lane. They now make upper arms to match the taller spindles, so it's a no-brainer. Mopar Action has always advised against using the taller pieces. Mopar Muscle, on the other hand, can't make up their mind. Some articles promote them, some articles say to avoid them. The MM loyal here will even be so ridiculous as to state that 'those articles against taller spindles are just reprints or from outside sources.' Glad to know that MM takes my safety so seriously. This has been a HOT topic for a long, long time and there has been some personal/professional debate between eberg and dulcich, so you would think that MM would at least take the time to read their own dang articles to have some degree of consistency. Anybody can take material from outside sources and reprint it verbatim without checking it. It ain't too responsible to do so, though.

The tubular arms have a slight angle to the upper ball joints to keep them from being over-stressed by the taller knuckles on pre-73 cars.
Here is why you need them:

For basic info about the swap, go to http://moparaction.com/Tech/archive/disc-main.html

Recent opinion posted here by Eberg of Mopar Action fame:

Quote:

On the steering knuckle "great debate":

(Here we go again!) Yes, the taller knuckles may give some small camber-gain improvement. But, IMHO, the tripling of bump steer (full travel) makes the swap a no-brainer: in a word, don't.

I've been doing lots of research into the original suspension design parameters of these cars. Incredibly complex, these guys (Highland Park engineers) actually had four seperate computer programs to analyze the angles and geometry. It seriously maxed out the (computer) hardware of the day - this was ~1960 were talkin'!

I've had at-length discussions with 4 of these guys (unfortunately 2 are now lookin' at the wrong side of the grass) and ALL thought the tall knuckle was a real bad idea.

The left-to-right flip (re: swaybar clearance) is another scary deal. If you take GREAT care to assure that the brake hose is properly routed and has enough length and friction protection for full lock / full-travel safety, then, sure. But I've seen too many - VERY many - cars where the hose acts as the rebound bumper! Please be careful! Rager proably had a point when he didn't wanna open this can of worms. The stuff I've done has always had either 100% factory engineering or contained caveats up the yazoo!

Guys will probably mention the MM article concerning this, here are my thoughts:
Here are the numbers from the MM compairison article. To start off, the front clip used was set not at stock height and rake, but 1 inch lower than stock height and at a rake of 1.5 inches. The reasoning was that 'most cars of today have a slightly raised rear' and the lower height was 'also quite common.' Ok, fine, you want to do a test that reflects common changes to mopar suspension, but to do this without the addition of a base test at stock height does nothing but leave doubts and conjecture. In my opinion, this test was fatally flawed by not doing a 'base test.'

But anyway, you can see the numbers below. The Toe change was excessive during extension, and this was dismissed by saying 'How often is your suspension fully extended on Main Street?' Sure, laugh and chuckle about the mental image of your roadrunner running through town a'la Bullitt, but what if it is? That's like saying you really don't need car insurance cause you don't plan on having accidents. It's a small point, but a point that carries throughout the test and the article. This was distrubing to me, especially since a 'full engineering study' was not conducted where some of these problems may become more pronounced.

The big red flag was the change in roll center. I'm sure you've seen the 'imaginary line' drawings that diminish into the pavement to illustrate this in the past, and you've probably understood it better as 'low center of gravity.' The greater the number, the less stable the car will be. If you look at the numbers below, you can see that the recommended A-body spindle had a range of 5.366 to 6.849, and the b-body piece 6.678 to 8.677. Woah, did I read that right? Yes, you did. The maximum on the 'recommended' spindle is dang near the minimum of the later B piece.

Another point of argument on these was that the ball joints would be over-angled and could fail. Supposedly a test was done by dulcich on various ball joints, and it was found that while newer joints are within thier intended range, factory or NOS pieces were not and risked failure.

Brought up by Ebooger was the fact that the A/E spindle was used by chrysler up to 76, well past the intro of the B piece in 73. If these spindles were ok to interchange, why not install them on everything and lower production costs and assembly line confusion?

To further this mystery along, MM continues to not be able to make up their mind, as I mentioned earlier. One article says they're safe, another says they aren't, and yet another recommends the use of the corrective tubular arms when used with the taller examples.If they're so great, why expensive new upper arms?

Bottom line here is that the late spindles probably can be (and have been) installed without a major catastrophe, but they are not a 'bolt-on replacement part.' The use of them will effect how your car handles, and everyone should read what's available on them before deciding one way or another. For me, the solution is simple. Either use the correct spindles, or buy the corrective upper arms.

Last but not least,

Posted By: 69 Road Runner

Re: Tall vs. Short Spindles - 10/30/05 12:44 AM

[quote}
Where can I get repros of the A-body knuckles? Unless they're crazy expensive, it might be worth just getting those for a future project rather than scrounging up another pair of the correct A's.
Clair

http://www.mpbrakes.com/sp2627.htm

This spindle includes caliper brackets but does not include the steering arm or lower ball joint.

Accepts the following components
Calipers 76-79 Dodge Aspen
Rotors 75-76 Dart,Swinger
Hoses 75-76 Dart,Swinger
Bearings A2, A17
Seals 5121

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 10/30/05 12:56 AM

Quote:

[quote}
Where can I get repros of the A-body knuckles? Unless they're crazy expensive, it might be worth just getting those for a future project rather than scrounging up another pair of the correct A's.
Clair

http://www.mpbrakes.com/sp2627.htm

Anyone measure these to see if they are not just F/M/J knuckles ???? Do these have any chrysler casting info on them (then they would be oem). I thought a while back someone caught a aftermarket supplier just selling the F/M/J knuckles as
A-body repros.

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 10/30/05 02:17 AM

Quote:

A "tall-spindle on a so equipped factory car isn't going to give you the same "bumpsteer" affect as putting them on an E-body, A-body or pre-72 B-body. The "points in space" are not the same (geometry is different). IIRC the taller spindle was required to compensate for the body insulator/Isolator/biscuit that arrived in the 73 B-body and F/J/M.

(edit)

Also realize that increased positive caster lowers the relative position of the outer tie rod hole in relation to the lower ball joint. So caster changes also change bump steer. Most race car adjust bump steer by adding shims to the outer tie rods (spherical ends) to move them up and down.

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 10/31/05 01:25 AM

Quote:

This says to me that the problem with bump steer is inherent to the F/J/M suspension design, not (necessarily) the extra height of the spindle. Unless, of course, swapping, er, chagning an F/J/M spindle out for a 73+ A-body spindle corrects the bump steer. If that's the case, this is a detail I have somehow missed until now.

**********

I think Rick was using it as an example of bumpsteer, as those cars were known to have bad bouts of it due to the oddly shaped t-bars. The point is that the taller spindles cause changes in bumpsteer through travel, causing similar habits as those of an F body. Not that the taller spindle is the cause of bumpsteer in an F.

That's exactly what I meant, sorry I wasn't clearer. On those cars, the tension strut is effectively double-hinged, and the angles/mounting points are different side to side. The later B-bodies also used the taller knuckles, but have good geometry, once you tighten up the longitudinals by eliminating the rubber isolators.

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 10/31/05 01:49 AM

Quote:

From the measurement I have seen, the taller spindle is �taller� from the spindle axis to the upper ball joint. Everything else is the same. That shouldn�t effect bump steer.

Not quite sure what you mean by 'spindle axis' - I would take that to mean a line drawn between the centers of the two wheel bearings. But what you seem to be saying, then, is nothing that happens above the lower balljoint matters - if the arc of the upper balljoint changes, then toe does not change? That's simply not true. Go change camber and see what happens to toe!

The proof is the chart somebody scanned way up this page, showing a total toe change of 0.081" for a stock knuckle, and 0.199 for the taller one. That's 2.5 times the bumpsteer. I've seen my own semi-blueprinted A-body with about 1/2 that much bumpsteer (mine's about 0.045", achielved by ovalling the idler arm hole and welding washers on), assuming that the ~0.2" from the chart above remains constant, that could be as much as 4.4 times the bumpsteer. And that's noticeable.

Here's my story. Over 20 years ago, I bought my '69 Valaint. I drove it around for a few weeks with the stock /6 3-on-the-tree setup, it was a total pleasure. Then I bought a new V-8 K-member from the local dealer, and did a 340 swap. 383 t-bars, etc. The car was a handful to drive fast. (not insane. Not racing. Just fast on anything but glass-smooth roads). Three alignment shops each tinkered with it and pronouced it "fixed". Not.

So I built some wooden bumpsteer gauges. It had, coincidentally, about 0.2". Again, it was real nasty to drive.

I fixed it, after researching the causes in some old Chrylser "Master tech" books (also reprinted in the MP chassis manuals) by the aforementioned idler mounting fix. K-members weren't (and aren't) precision pieces!

Now I can go to a road course and humiliate most Porsches.

Rick

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 10/31/05 01:53 AM

BTW, I was skeptical, so I destructive-tested the Master Power knuckles when they first came out. How? Low-tech. Put 'em in a 12" vise and beat 'em to a pulp with a really big hammer. They bent. They did not crack or break! They are drop-forged, probably better than the originals.

Rick

Posted By: 69 Road Runner

Re: Tall vs. Short Spindles - 10/31/05 02:18 AM

Rick, what's your opinion on using the later spindles with the tubular control arms? Does that fix the concerns that you have?

Posted By: BergmanAutoCraft

Re: Tall vs. Short Spindles - 10/31/05 03:12 AM

WOW, I didn't realize this was such a hot topic. I still plan to give the drop spindles a whirl, since nobody else seems to be interested in as an agressive stance as I am. I do plan to try to measure the bumpsteer during mock up...

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 10/31/05 01:35 PM

Quote:

Rick, what's your opinion on using the later spindles with the tubular control arms? Does that fix the concerns that you have?

No. Modified or tubular upper control arms can change caster or camber, but can't fix the altered geometry / toe pattern.

Maybe I'm thick...? But the correct, OEM-engineered knuckles are readily available, repro or used. Since the OEM setup is known / proven to have minimal bumpsteer, and the tall knuckles are known to be a problem, why not just do it right?

Here's another E.G. from my limitless stash of stories:

One of the first years I ran the One Lap of America in my Valiant, two guys - great guys - from western Canada showed up in a pink Charger. They had the tall knuckles, calipers swapped, and I noticed the brake hoses were way too short and/or misrouted. I helped them fix that before the event began.

They claimed that the car had "perfect alignment". And it seemed fine on the highway sections. But on the track, they spun the car, went off, etc., repeatedly. I've always wondered how much of their grief was due to large amounts of bumpsteer.

Rick

Posted By: Clair_Davis

Re: Tall vs. Short Spindles - 10/31/05 04:12 PM

GMachine,
I'm interested in them, since I'd like to have some extra travel in the suspension for the sake of overkill, but I'm not really having a problem with suspension movement with the 1.14" bars. Add to that the fact that I'd almost certainly HAVE to go with tubular uppers to regain the clearance I'd lose at the UBJ with the taller spindle... I think I'll let you blaze that trail for me...

If/when I get the urge to go with 17x9's up front, I'll probably have to go there.

Are you thinking about the Fatman spindles? I don't suppose they took any time to look at A/B/E bump steer issues since they were trying to crank out a spindle for the street rodders to use on their Aspen/Volare front end swap kits...

Clair

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 10/31/05 06:56 PM

Quote:

Not quite sure what you mean by 'spindle axis' - I would take that to mean a line drawn between the centers of the two wheel bearings. But what you seem to be saying, then, is nothing that happens above the lower balljoint matters - if the arc of the upper balljoint changes, then toe does not change? That's simply not true. Go change camber and see what happens to toe!

Yea, when you change your camber you toe changes. But we're talking 1/8" difference toe change with the taller spindle.

Would you agree that a positive caster change lowers the rear tie rod end hole and thus ALSO changes bump steer?? I think changes with 4-5 degrees will see similar bump steer effects.

Also a lot of caster induces scrub when the wheel goes through its turning motion. Also it will change the cross percentage on a set of scales which sort of upsets the car in a corner. Even though there are some bad effects of caster, on a production based car the cornering is improved because it gives you some camber effect when the wheel is turned.

The suspension geometry deal is a game of compromises. When something is perfect something else get worse.

On our race team we set bump steer to the .005. And we have gone out to a race, made changes, won the race, and afterwards the bump steer was way off. Oh well, still won.

There are some aftermarke setups with horrible bumpsteer. I personally just haven't seen 1/8" at 4.5 travel beeing a big difference.

What I wrote above about bump steer and the lower half of the spindle occurs in only one specific case that doens't really happen in the real world. I edited that out. Sorry about that.

Quote:

They claimed that the car had "perfect alignment". And it seemed fine on the highway sections. But on the track, they spun the car, went off, etc., repeatedly. I've always wondered how much of their grief was due to large amounts of bumpsteer.

That's a lot of inferences. There could have been a ton of reasons for that. You need a back to back test run with the two different bump steers ONLY to see the bump steer affect. The taller spindle on a race car that is dialed in will need a different setup because the roll center went up (understeer) and the front tire temps should be better (more grip/oversteer) because camber is better.

I just like the taller spindles for the performance potential of more camber gain. That is sooo key in get good front tire grip and good tire temps at the track. For me, I'd just adjust out the bumpsteer if it was way bad from factory to start with.

Posted By: Digger

Re: Tall vs. Short Spindles - 10/31/05 09:26 PM

To anyone thinking of buying the Fatman spindles you might want to read this discussion first: http://www.streetrodstuff.com/Roundtable/Archives/Year_2002/February/255.php
One person reports a spindle broke and others complain of other problems.

Posted By: Digger

Re: Tall vs. Short Spindles - 10/31/05 10:21 PM

FYI, the site: www.piratejack.net/spindle.html is listing new spindles with brackets for $210. Don't know if they are the same source as MP Brakes, The Paddock and YearOne or not.

Posted By: nd65

Re: Tall vs. Short Spindles - 10/31/05 11:32 PM

Can someone tell me in simple language, what can happen to a car if the taller spindles are used? I am not grasping the bumpsteer stuff.

Will parts break, wear out quicker, handle poorly- in what manner etc?

I dont put that many miles on my car, so I can handle replacing a few parts occasionly. However, I would not want to risk anyones safety.

This is a street car, not a racecar.

Posted By: BergmanAutoCraft

Re: Tall vs. Short Spindles - 11/01/05 12:05 AM

The spindle debate is merely, can we replace our A/E spindles with the 3/8" taller more plentiful F,M,J,M,R and 73 up B body units. This started, because I mentioned I ordered the fatman spindles, which allow me to lower my car more, and use more t bar preload in the process. Now, everyone is claiming there is an excessive toe change through the suspensions range of motion if the taller spindle is used (bumpsteer). I am still debating sending the spindles back, but I'd like to see them in my hands before I make that decision. For all practical purposes I'm sure tere would be no ill effects for the swap, but with at least on place making new replacement spindles it isn't necessary to go that route. I am stuck with the taller spindle, because noone makes a drop spindle based on the A body design.

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 11/01/05 01:13 AM

Quote:

because noone [sic] makes a drop spindle based on the A body design.

...I'm pretty sure there are some good ones, properly forged, made in Australia. Not sure if they are '73-up or '72-down though.

Rick

Posted By: BergmanAutoCraft

Re: Tall vs. Short Spindles - 11/01/05 01:50 AM

Worth looking into. If you know who is selling them, please let me know. bergmanr@optonline.net. thanks!

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/01/05 03:06 AM

First the tall spindle detractors claimed it would overextend teh ball joint. That argument was shot down so now they claim it'll cause bumpsteer.

That claim merely shows thier lack of understanding of front suspension design and the definition of bumpsteer.

Bumpsteer is caused by the tierod assembly moving in a different arc from the inner and out pivots of the LOWER CONTROL ARM. The height of the spindle will never change the relationship of the tie rod assembly to the lower control arm. In fact what bumpsteer that is inherent to the mopar front suspension is due to the torsion bars being where the inner tierod pivot should be.

Bumpsteer is a change in the direction of the tire as the assembly moves up and down. It affects toe and steers the car in a manner inconsistent with the driver's input.

What a taller spindle can cause is a change in toe as the spindle moves up and down. In the taller spindle test written up in MM what could be called excessive toe change occured at max droop. It could be said that the taller spindle merely accentuates any bumpsteer issues you have. BTW, if you expect good handling with your UCA on the bumpstop then you live somewhere outside the realms of physics.

Anyway, you might say the effect of the taller spindle at full droop is identical to bumpsteer (you'd be right) but the cure is completely different and they are different problems even is the SYMPTOM is the same or similar.

Now I am sure the bumpsteer fans will say 6 of one or a half dozen of the other. Well, words are all we have here and if you can be bothered to use them right then you are not likely to be taken seriously by those who do know what the words mean. Which is exactly how internet myths perpetuate.

Posted By: Digger

Re: Tall vs. Short Spindles - 11/01/05 04:13 AM

Here's a concise technical description of bump steer: www.racerpartswholesale.com/longtech3.htm It suggests that the upper ball joint position at least plays a minor role in bump steer. This link: www.bakerprecision.com/longacr17a.htm describes how to measure bump steer. It sounds like somebody needs to take the time to make the measurements to put this matter to rest.

Posted By: Montclaire

Re: Tall vs. Short Spindles - 11/01/05 04:25 AM

Quote:

First the tall spindle detractors claimed it would overextend teh ball joint. That argument was shot down so now they claim it'll cause bumpsteer.

Yes and no. It was found that ball joints built to stock specs, or NOS examples, will bind. Replacements, for whatever reason, will come very close to their limits, but do not bind. At least most won't. I'm sure a few out of hundred would, depending on the manufacturer.

Posted By: 340duster340

Re: Tall vs. Short Spindles - 11/01/05 05:02 AM

here are some thoughts from a mechanical engineer who worked for FoMoCo, and is currently working at a leading product development firm, i also have 7 years diagnostic auto experience, and have had a few dusters and darts.

I WOULD NOT MODIFY STEERING GEOMETRY UNLESS a) you were a trained and certified chassis builder or b) using factory approved parts

basically these vehciles are designed to used stock parts, in stock locations, and changing suspension geometry could cause a loading condition that the structure was not designed for which could lead to failure and drastically altering or mis-matching parts could also cause premature failure. this should be common sence.

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/01/05 05:48 AM

Quote:

Here's a concise technical description of bump steer: www.racerpartswholesale.com/longtech3.htm It suggests that the upper ball joint position at least plays a minor role in bump steer. This link: www.bakerprecision.com/longacr17a.htm describes how to measure bump steer. It sounds like somebody needs to take the time to make the measurements to put this matter to rest.

Well like Rick said the measurements are right here in the table made by Bill Reily published in Mopar Muscle.

Quote:

Bumpsteer is caused by the tierod assembly moving in a different arc from the inner and out pivots of the LOWER CONTROL ARM. The height of the spindle will never change the relationship of the tie rod assembly to the lower control arm. In fact what bumpsteer that is inherent to the mopar front suspension is due to the torsion bars being where the inner tierod pivot should be.

That exactly what I was trying to say in an earlier reply but after Rick's reply I re-thought it and second guessed myself and edited out my comments. I think the end outcomes do effect bumpsteer in a round about way.

I think the effect comes from the camber curve changing as you said Thunderstruck. As the camber changes inward the tie rod pushes out the toe. This is when the tie rod is on a higher plane than the lower ball joint. Even though the tie rod and lower control arm are on the same arc, they almost always are not on the same plane.

Posted By: blown340

Re: Tall vs. Short Spindles - 11/01/05 06:11 AM

Quote:

-SAE Mini Formula Design team suspension design and team leader for scratch built race car.

Hi there autoxcuda.. Well, I'm staying out of the conversation since my opinions are based on theory and I've never had a F body spindle on a car...

I just wanted to say though that its cool to see another Formula SAE alum on the board! I had the pleasure of working on 5 of the cars while I was in school and also was in charge of suspension design for 3 years. I also suffered the wrath of being the team captain for 3 of those years as well.

-Jon

Attached picture 2109534-seniorproject.jpg

Posted By: ThermoQuad

Re: Tall vs. Short Spindles - 11/02/05 12:08 PM

Here is a bump as I am hoping an engineering discussion will emerge from all of the hearsay, opinion and ego.

Maybe you experts could discuss the data from the MM article a little deeper. Perhaps a real world study should take place where you took another test car and measured the bump steer/alignment angles differences between the changes. The final test would compare lap times and g forces thru the turns at say Watkins Glen. Until this is done the only real data we have is the one magazine article and a bunch of opinion. I am not asking for anyone to fall on their torsion bar [sword]

but lets get to the facts.

Posted By: DJVCuda

Re: Tall vs. Short Spindles - 11/02/05 02:46 PM

the opinions experessed are have thier points, BUT facts are facts, and I would like to know fact from opinion!

Maybe Bill from bigblockdart.com can help???

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 11/02/05 06:02 PM

Quote:

It sounds like somebody needs to take the time to make the measurements to put this matter to rest.

Quote:

Well like Rick said the measurements are right here in the table made by Bill Reily published in Mopar Muscle.

Yes, look up near the beginning of this thread. As I said:

Quote:

The proof is the chart somebody scanned way up this page, showing a total toe change of 0.081" for a stock knuckle, and 0.199 for the taller one. That's 2.5 times the bumpsteer. I've seen my own semi-blueprinted A-body with about 1/2 that much bumpsteer (mine's about 0.045", achieved by ovalling the idler arm hole and welding washers on), assuming that the ~0.2" from the chart above remains constant, that could be as much as 4.4 times the bumpsteer. And that's noticeable.

While I have no idea whom the guy is who did the measurements, presumably, since he was (I'm told) trying to build a case for the tall knuckles, it stands to reason that if it was fudged, it would been fudged in the other direction!

Picture an imaginary knuckle where the upper section had been made, say, 10 inches taller (also see diagram way up in this thread). Nothing else changes. Now the UCA is at a bizarre angle (no longer approx. perpendicular to the steering axis (ball joint axis), and the top of the knuckle moves in and out along what's now a crazy arc that moves the upper ball joint way in and out from jounce to rebound. Camber changes, bigtime, right? And what happens to toe during the travel? Ta-dah!

In another everyday example: Go get your front end aligned. What's the last adjustment they make? Right! Toe! That's because ANYTHING that changes camber will change toe.

Chrysler's engineering credo for these cars (published) was:
"...at some acceptable caster / camber setting, the amount of toe change can be set or corrected to zero which will yield an ideal toe patten.�

Why screw with that? While there are zillions of instances where aftermarket parts far surpass OEM stuff (and the reverse is equally true!), there are no re-engineered aftermarket knuckles � only ones where the spindle has been moved. Jeez. These cars had MUCH better - DEMONSTRABLY better - geometry (not to mention torsional rigidity, unsprung weight, strength, etc.) than their contemporary competitors. Why screw that up?

I�ll give somebody (or everybody) else the last word. I�m done!

Rick

Posted By: DJVCuda

Re: Tall vs. Short Spindles - 11/02/05 06:57 PM

Quote:

http://www.bigblockdart.com/tech/spindles.shtml

2nd post on this subject.. I hope bill will chime in here...

Posted By: NJK66

Re: Tall vs. Short Spindles - 11/02/05 07:05 PM

I am the person who originally asked the question about the taller spindles and I never expected this degree of response. There is a lot of good information here but I asked the question a ways back and I don't think it ever got answered. From a geometric standpoint, it sounds like there is a toe issue when the front end is fully extended and it also sounds like there is potential for more than normal stress on the upper ball joint. But what I want to know is does the taller spindle make the front end geometry so bad there is a potential for catistrophic failure of the upper ball joint? Or will the vehicle steer so bad it is downright dangerous. Remember this is a street driven car with only an occasional pass down the drag strip.

Posted By: DJVCuda

Re: Tall vs. Short Spindles - 11/02/05 07:12 PM

I am no way an engineer, BUT after reading bills article, I went ahead and swapped from drums to discs on a 70 challenger using 78 dippy spindles, before the alignment the tops of the tires were sticking out toward the fender further, but after an alignment all was well, it aligned fine, and it has seen a few thousand miles this summer, drag strip time, and putting it thru it's paces with the new KYB's on and it's FINE....

Posted By: 71charger

Re: Tall vs. Short Spindles - 11/02/05 08:42 PM

I've never noticed any detrimental change in the handling. Personally, except for the slop in the steering gear, I think the car handles great. I've had a few great handling cars (Shelby Charger (turbo and non-turbo), Shelby Lancer, Daytona Turbo Z, Daytona Shelby Z, Shadow with a CSX's suspension in it). My current daily driver is a Neon R/T. I do enjoy a vehicle that handles well. If someone wants to buy me new balljoints I'd be happy to put them in and give you the ones that are in the car so you can see what 12 years of wear looks like with the taller spindle. If the bone yard had had the 73-76 A body spindles I would have used them. They didn't so I put in the F-body. I don't regret it for a second.

If anyone that lives around here wants to see the taller knuckles installed, drop me a line and come on over. If the weather's nice we can take it out for a ride.

Posted By: Montclaire

Re: Tall vs. Short Spindles - 11/02/05 09:55 PM

All I have to say is, 'tech archives, please."

Posted By: patrick

Re: Tall vs. Short Spindles - 11/02/05 10:11 PM

Quote:

I am the person who originally asked the question about the taller spindles and I never expected this degree of response. There is a lot of good information here but I asked the question a ways back and I don't think it ever got answered. From a geometric standpoint, it sounds like there is a toe issue when the front end is fully extended and it also sounds like there is potential for more than normal stress on the upper ball joint. But what I want to know is does the taller spindle make the front end geometry so bad there is a potential for catistrophic failure of the upper ball joint? Or will the vehicle steer so bad it is downright dangerous. Remember this is a street driven car with only an occasional pass down the drag strip.

short answer, no to both questions, especially if you replace the original upper ball joints with some good aftermarket moogs.

Posted By: BergmanAutoCraft

Re: Tall vs. Short Spindles - 11/03/05 12:02 AM

I didn't start this debate, but my concern is that I want to lower the car, and fatman is the only maker of drop spindles, but they are based on the taller F body units. Bill Reilly was kind enough to explain the whole thing to me with numbers from his finding on the comparison. He has put me at ease that this is not an unsafe condition, especially if I check/set the bumpsteer in the process. I certainly take his findings over Ehrenbergs opinion on this one, sorry Rick...

Posted By: AndyF

Re: Tall vs. Short Spindles - 11/03/05 12:08 AM

Have you had a set of the Fatman knuckles in your hand yet? I'd never put them on a car that I was going to be driving hard so I'll be interested in what you think once you see them.

Posted By: BergmanAutoCraft

Re: Tall vs. Short Spindles - 11/03/05 12:44 AM

Mine should be here any day, ordered last week. Bill Reilly has a set he is trying on an e body. He says they are extremely beefy. I will keep you posted.

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/03/05 02:45 AM

Quote:

Picture an imaginary knuckle where the upper section had been made, say, 10 inches taller (also see diagram way up in this thread). Nothing else changes. Now the UCA is at a bizarre angle (no longer approx. perpendicular to the steering axis (ball joint axis), and the top of the knuckle moves in and out along what's now a crazy arc that moves the upper ball joint way in and out from jounce to rebound. Camber changes, bigtime, right? And what happens to toe during the travel? Ta-dah!

In that extreme case you're right. And even in the not extreme case. But even in that extreme case you can reset the toe. Then adjust the bump steer and fix it. The reset/check the toe again. We have big upper A-arm angles in our race car and have less that .005 toe though the travel mentioned.

But there again, you fix the toe to make it better.

Do 99% of the people doing a disk upgrade have the tools and capability or even want to bother with bump steer checking and correcting thier car? The answer is NO.

I look at the tall spindle for a specific performance enhancement. Not a "I can't find A-body spindles" deal. The toe issue in a minus on the F-body spindle. For ME, I can adjust out the bump steer easier than I can get the added camber gain to give me a better contact patch while racing. It's a compromise I can overcome for what I want out of the car.

Most are not even looking for the camber gain. Or have the rest of the package to take advantage of it.

Quote:

Jeez. These cars had MUCH better - DEMONSTRABLY better - geometry (not to mention torsional rigidity, unsprung weight, strength, etc.) than their contemporary competitors. Why screw that up?

Ageed for their production cars. But even changing the bump steer changes the suspension geometry technically. And that was an improvement that was felt on the Valiant.

If you're racing, the goal and purpose of the handling has changed. There is room for geometry "changes" to meet those goals. I wouldn't say "improvement" over stock because they (Mopar) weren't building for such a specific audience. "improvement" is not really fair when the objective and constraints have changed.

I got and email from a E-Body dirt track racer in Nebraska. He was having problems adjusting enough right side front camber to get good traction and tire temps across the tire. I told to bolt on a right side A-body lower control arm since it was longer. He got more camber. Car handled better in turns, lap time were better, and he was tickled pink. I sure the bump steer got worse when he did this. And I bet he didn't fix the bump steer. I bet he could been a little faster if he did fix the bump steer. But bottom line, he was faster than before.

To meet specific goals you can break the mold. You wouldn't run a longer LCA on one side of your street car. But for this guy for this application it worked out.

Posted By: BergmanAutoCraft

Re: Tall vs. Short Spindles - 11/03/05 02:52 AM

Auto X - what method did you use to correct the bumpsteer. The MP manual mentions the heating and bending of the forged steering arms, and anything else that needs "adjusting". How do you feel about it?

Posted By: AndyF

Re: Tall vs. Short Spindles - 11/03/05 03:20 AM

I know that Dick Ross at Firm Feel uses the taller knuckles primarily because of the better camber gain. They are also 1.5 lbs lighter which means a lot for some types of racing. Dick says he can get them to bump just fine. I don't mess around with suspensions enough myself to have hands on experience plotting and resolving camber gain curves and bump curves but I respect Dick's experience in this area.

I have been asked by one company to design a dropped forged aftermarket Mopar knuckle that is even taller than the FMJ knuckle. If that project ever happens just imagine the debate on this board!

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/03/05 04:18 AM

Quote:

Auto X - what method did you use to correct the bumpsteer. The MP manual mentions the heating and bending of the forged steering arms, and anything else that needs "adjusting". How do you feel about it?

Slot the K-member thru bolt and shim the steering box. Directions in the MP Chassis book. Be carefull that might run into header clearance issues. If that doesn't get you far enough. Put heim on the ends of your tie rods and drill the steering arm hole taper out. Then run a thru bolts and shim as needed. Go to the circle track stuff. They have shim and bolt kits. We did this with our circle track GM metric spindles.

Jeff at www.racecarfactory.com has the bolt kits and heims.

Posted By: BergmanAutoCraft

Re: Tall vs. Short Spindles - 11/03/05 11:19 AM

Thanks, but heims positively suck on the street. They get lose and make noise. Maybe on a race they're ok, but not suitable for street. I will be working on this in depth over the next week or two.

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 11/03/05 02:42 PM

Ok, you sucked me in again... ;->

Quote:

...you can reset the toe. Then adjust the bump steer and fix it. The reset/check the toe again.

You're missing the crux of the problem. Sure, I have no doubt whatsoever that for track-only cars, specific applications, etc., there are setups better that OEM/dead stock. But do you really think the person who asked if this was a good bolt-on swap is gonna do that? Do you think even one in 100 alignment shops knows how (or will take the time) to do that? Or, will the guy who's doing the swap, who is using the Volar� knuckles to save $$$, wants to spend 5X what he saved on the knuckles at a race chassis shop?

Megadittos on heim joints for the street. Same deal. Awesome, easy to adjust, quick to fabricate links and arms for race cars, be they drag, circle track, or road course. But about ase useful as teats on a bull for street use! (They pound out from road shocks, and most that I've seen have no provision for lubrication and/or environmental seals.) I highly doubt (a guess) that the typical ones are anywhere near as strong a a stock tie-rod end. Good thing they are (when installed correctly) fail-safe!

On the weight issue: '73-up drum knuckles are even lighter and maintain correct A/62-72 B/E-body geometry. When used with Andy F's awesome Viper caliper kits, you have the best of everything.

One detail (?) that has been conveniently glossed over: When the tall knuckles were introduced (73), if they were better / lighter, and did the job, why didn't the Highland Park guys specify them for A and E cars, too? Mega-corporations love standardization! Because - from their lips to my ears - they had a "negative impact on the geometry that we had worked so hard to get right." Remember, these knuckles were only designed out of sheer necessity, because the rubber-isolated K-members resulted in a taller overall package, incl. higher upper control arm pivot points.

Will Joe Blow in his cruiser notice the difference? Maybe. Maybe not. Look, when these orignal Mopar suspensions were introduced in the early '60s, the competitor's designs were deficient (as per published SAE papers.) Nobody (magazine road testers, the buying public, etc.) said that Chevies of Fords had lousy suspension geometery. Most just said that Mopars handled better. Some of that was, no doubt, due to the platform-rigidity differences, less overall and unspring weight, etc., as well as the geometry differences. But most people attributed it to the "Torsion-Aire" setup, which, in and of itself, played a relatively minor role (reducing usprung weight and moving mass back and down in the chassis). Drive a 62 b-body - dead stock, 318 car, 5" wheels, bias plys, then drive any 62 Ford or, especially, a Chevy. OhmyGod!

Rick

Posted By: moparx

Re: Tall vs. Short Spindles - 11/04/05 03:03 AM

rick,[or any one else...] please answer this question : IF you have "unacceptable" bump[how much would be ideal ? .005-.010 ? .015-.025 ?], which way would you have to go to correct it ? and by approximately how much ? an example could be too much toe in[or out]in bump, but maybe too much toe out in rebound. i hope i'm making sense. also, what is a reasonable [?] amount of suspension travel ? 3 1/2" ? 5" ? more ? i have tried to start discussions on front suspension geometry before, as i am fabbing a complete deal for my 33 dodge "humpback", but nobody wants to respond. LOTS of discussion on this spindle topic tho.......you guys are tons smarter than me, so help me out here ! thanks !

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 11/04/05 03:23 AM

Indy cars want to see a few thousandths, max. As someone posted earlier, on a dirt track car with constant tire slippage, 1/2" might be OK! On a smooth-track road racer, 1/8" would probably be alright (becasue the full-rebound travel is rarely, if ever, seen), although some tracks I've been on - notably Lime Rock, (CT), will use full travel - I mean FULL - every lap (more so years ago before the layout was modified - you hadda turn in while the car was airborne.) The few factory specs I've seen were 1/4", but I can tell you, from experience, that's pretty bad. Maybe with old bias-ply, 80-profile tires granny wouldn't notice it. But with 40 series, 35 psi, etc - forget it.

Let's put it this way - the ideal number is zero. You ain't gonna see that! So simply do your best, then drive the car. If it doesn't seem to have any bad habits (to you) - you're done! Several posts earlier in this thread indicated total satisfaction with a setup that unquestionably wasn't as good as it could be. If they're happy, I'm happy.

Now this is really into redundancy - sorry. The main point that I'm trying to make is: If you had a choice of 2 different engine components, they weren't very differently priced, but one was widely known to work significantly better than the other, and recommended by the guys who designed your engine, you'd pick the winner, right? Why should steering knuckles be any different?

Rick

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/04/05 04:39 AM

Quote:

One detail (?) that has been conveniently glossed over: When the tall knuckles were introduced (73), if they were better / lighter, and did the job, why didn't the Highland Park guys specify them for A and E cars, too? Mega-corporations love standardization! Because - from their lips to my ears - they had a "negative impact on the geometry that we had worked so hard to get right." Remember, these knuckles were only designed out of sheer necessity, because the rubber-isolated K-members resulted in a taller overall package, incl. higher upper control arm pivot points.

Several reasons.

I'll bet a donut that in 73 the A body was already slated to go bye bye and the vehicle that became the F body was being designed. CC wasn't gonna spend any money redoing or reengineering or verifying the A body front suspension for a new spindle. So they stuck discs on it basically using a modded drum spindle that was know to be satisfactory.

Second, production cars are designed for drivers that suck. So lots of conservative specifications are used. Which is exactly why the taller spindle wasn't used, because then production tolerances would have to be tightened up to limit toe change issues and it was cheaper to not do that. Engineers are not told, "you have unlimited bux, build the best you can". They are told "get it done as best you can for $XXX."

So you get compromises. Of course you neglect to mention the A body front suspension was designed in the late 50's when bias plies ruled and in 73 radials were gettin common. Radials with better grip, especially in a handling situation. That change alone makes the case for optimizing the front suspension. What was ok for bias ply tires still works with radials, but it could be so much better if it were optimized.

Posted By: moparx

Re: Tall vs. Short Spindles - 11/05/05 03:00 AM

rick, thanks for the response. but now, if i want to reduce "bump" , which way do i go[raise/lower]with the tie rod ? and also, by how much to gain approximately ????? in my situation, i have stayed within a tolerance of .005-.015 on all of the components i have fabbed so far, [including the positioning of same] & i would like to keep the bump within the same specs if it's possible. i realize this may be getting slightly off topic, but in order to correct "bump", others may find this info usefull as well.

Posted By: TC@HP2

Re: Tall vs. Short Spindles - 11/05/05 06:34 AM

Quote:

I have been asked by one company to design a dropped forged aftermarket Mopar knuckle that is even taller than the FMJ knuckle. If that project ever happens just imagine the debate on this board!

If that happens I'll buy a set from you. Make a set with a 2" drop in them, and you won't be able to build them fast enough.

I've heard mixed reviews on Fatmans spindles, all of it from street rodders. They accomplish the drop alright, but don't appear to be real stout, nor particularly decent looking. However, that info is a couple years old so they may have come up with a new or better design since then.

Other brands have been converting to taller spindles for handling improvements for decades. It only seems to be in the Mopar camp that this is an ongoing debate.

Posted By: patrick

Re: Tall vs. Short Spindles - 11/05/05 01:40 PM

one thought on the whole toe issue:

at full extension you have .186 degrees toe-in and at full dive, you have .013 degrees toe out. when you go around a corner, what happens? the outside wheel compresses, the inside extends. so what does this show? by reducing toe-in on the outside, and increasing it on the inside, that's effectively not steering the wheels quite as far (note, we're talking tenths of a degree), so I would assume the car would understeer slightly more. but at the same token, the higher roll center, improves roll resistance slightly, so the car should lean slightly less going around a corner, so in the end, it should pretty much be a wash.

around here, you can't find A bodies in a junkyard, let alone disc brake ones, so the A body spindles fetch $150-300. but there's dippy's and 5th ave's everywhere, and you can get the spindles from a yard for about $20-30. in fact, I wanted the large rotor caliper brackets for my car, and the yard said $30. I couldn't get them off with a wrench, so they lifted the car up, and cut the upper and lower control arms, and let me have both assemblies (spindle, adapter, caliper, rotor, and 15x7 wheels!) for $30. this was off an '80 or 81 5th ave (R body)

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/06/05 06:30 AM

Quote:

Ok, you sucked me in again... ;->

Sorry about that.

Quote:

You're missing the crux of the problem. Sure, I have no doubt whatsoever that for track-only cars, specific applications, etc., there are setups better that OEM/dead stock. But do you really think the person who asked if this was a good bolt-on swap is gonna do that?

No, I agree. Like I ageed before

Quote:

Do you think even one in 100 alignment shops knows how (or will take the time) to do that?

No. Agree again.

Quote:

Or, will the guy who's doing the swap, who is using the Volar� knuckles to save $$$, wants to spend 5X what he saved on the knuckles at a race chassis shop?

Nope.

Quote:

Megadittos on heim joints for the street. Same deal. Awesome, easy to adjust, quick to fabricate links and arms for race cars, be they drag, circle track, or road course. But about ase useful as teats on a bull for street use! (They pound out from road shocks, and most that I've seen have no provision for lubrication and/or environmental seals.) I highly doubt (a guess) that the typical ones are anywhere near as strong a a stock tie-rod end. Good thing they are (when installed correctly) fail-safe!

Agreed. Don't know how much Peter drives it. Just giving possible options. Trying to look outside the box.

Quote:

One detail (?) that has been conveniently glossed over: When the tall knuckles were introduced (73), if they were better / lighter, and did the job, why didn't the Highland Park guys specify them for A and E cars, too? Mega-corporations love standardization! Because - from their lips to my ears - they had a "negative impact on the geometry that we had worked so hard to get right." Remember, these knuckles were only designed out of sheer necessity, because the rubber-isolated K-members resulted in a taller overall package, incl. higher upper control arm pivot points.

Like I said before. It's not a competition between the two spindles issue. Because IMO they're each running in "different" races. OEM setups have tons of criteria and contraints to follow in thier designs. AND most the people wanting to use F-body spindles for the lack of finding A-body spindles to do simple disk swaps have the same criteria and constaints.

Posted By: Montclaire

Re: Tall vs. Short Spindles - 11/06/05 06:46 AM

Quote:

I'll bet a donut that in 73 the A body was already slated to go bye bye and the vehicle that became the F body was being designed. CC wasn't gonna spend any money redoing or reengineering or verifying the A body front suspension for a new spindle. So they stuck discs on it basically using a modded drum spindle that was know to be satisfactory.

That doesn't make sense. The sole reason that the taller spindles were introduced was to return the suspension on iso-k cars back to the proper geometry found in earlier models. This gets confusing because the bent t-bar setup of the F-bodies and others is an engineering nightmare and also causes bumpsteer problems. Some chrysler engineers actually left the company over the whole bent t-bar thing, as they felt it was detrimental to the good reputation their design(s) had developed over the years.
Now that I'm thinking about this though, what would happen of you installed the k-frame spacers from the 73 and on iso-k cars onto a 72 or older car with the taller spindles? Shouldn't that return things to the proper geometry, and everybody would live happily ever after with their cheap-o taller knuckles and aluminum k-frame spacers?

-->Rick, I'd like to talk to you about the POR pro rally, if you remember the article you did on it years ago. You campaigned a plymouth turismo and got a DNF after sucking mud down the air intake. I'm thinking of doing something similar and was looking for some information, please PM me if you'd like to discuss it.

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/06/05 08:42 AM

Quote:

Now that I'm thinking about this though, what would happen of you installed the k-frame spacers from the 73 and on iso-k cars onto a 72 or older car with the taller spindles? Shouldn't that return things to the proper geometry, and everybody would live happily ever after with their cheap-o taller knuckles and aluminum k-frame spacers?

The T-bars would end up angled, the driveshaft pinion angles changed, fan shroud offset. I also doubt the spindle was heighten JUST for the iso-k-frame.

Posted By: Montclaire

Re: Tall vs. Short Spindles - 11/06/05 06:10 PM

Quote:

The T-bars would end up angled, the driveshaft pinion angles changed, fan shroud offset. I also doubt the spindle was heighten JUST for the iso-k-frame.

I suppose it's more trouble than it's worth, and now that you said that, I'm guessing that the t-bar mounts are lower in 73-74 b-bodies. I've never owned one and they aren't the most popular body style, so I can't say for sure.
How can you say that you doubt the spindles were heightened just for the iso-k? That's exactly why they were heightened, to maintain the geometry of the non-iso cars.

Posted By: Clair_Davis

Re: Tall vs. Short Spindles - 11/06/05 07:53 PM

Why not LOWER the UCA mounting points to match the dimensions of the pre-iso-K cars and keep the A-body spindle?

RE: AndyF's spindle, using stock UCA's, I don't think I can tolerate a spindle that's much taller with the 5.7" BS wheels I've got. If it's possible to go significantly taller and not reduce my wheel/tire options, it would be worth it, even if it meant having to go with aftermarket UCA's. If that's not the case, I'll keep wider rubber up front and stick with the OEM spindles...

Here's another vote for the Tech Archives!

Clair

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/07/05 12:00 AM

Fatman Spindles #1

Attached picture 2123342-aDSCF1135.jpg

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/07/05 12:01 AM

Fatman Spindles #2

Attached picture 2123343-aDSCF1136.jpg

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/07/05 12:01 AM

Fatman Spindles #3

Attached picture 2123346-aDSCF1137.jpg

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/07/05 12:02 AM

Fatman Spindles #4

Attached picture 2123349-aDSCF1138.jpg

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/07/05 02:40 AM

Quote:

That doesn't make sense. The sole reason that the taller spindles were introduced was to return the suspension on iso-k cars back to the proper geometry found in earlier models. This gets confusing because the bent t-bar setup of the F-bodies and others is an engineering nightmare and also causes bumpsteer problems. Some chrysler engineers actually left the company over the whole bent t-bar thing, as they felt it was detrimental to the good reputation their design(s) had developed over the years.
Now that I'm thinking about this though, what would happen of you installed the k-frame spacers from the 73 and on iso-k cars onto a 72 or older car with the taller spindles? Shouldn't that return things to the proper geometry, and everybody would live happily ever after with their cheap-o taller knuckles and aluminum k-frame spacers?\

You are making one critical error in your thinking. The upper control arm inner pivot in the transverse torsion bar suspension is NOT mounted on the unibody like the earlier Mopars. It is mounted to the K member. Chrysler could have made the distance between the UCA and LCA inner pivots any spec they wanted, they could have matched the early torsion bar suspension specs in a heartbeat.

The rubber isolators used between the K member and the body on the later Mopars have NO bearing on spindle height, period. Those rubber isolators were used for one purpose only, to smooth out the ride as felt from the passenger compartment. Obviously handling wasn't an issue here. And yet they saw fit to heighten the spindle.

Apparently, Chrysler saw a problem with the later geometry and fixed it with a taller spindle. Why? It sure wasn't because of the isoclamp setup. In fact I would be curious to know the distance between an A body's UCA and LCA inner pivots vs. the F body UCA and LCA inner pivots. If they are the same, or the F body's is less than the A body's, that pretty much blows the "no tall spindle" argument out of the water. If the F body's is taller, well that might not prove anything. I don't know these specs, maybe if I can find my FSM's I can dig that up.

You must remember the first A body came out in 1959, with the 1960 (model year) Valiant, and as far as I know the critical dimensions are the same till the end in 1976. The F body came out in 1975 (1976 model year), which means that the F body should have had at least 16 years more suspension design theory and experience (including the domination of NASCAR in the 60's) than the A body. Assuming similar lead times in design and development of the two new vehicle lines. Granted the Transverse Torsion bar isn't perfect, but it did have the benefit of a lot more experience than the A body suspension did. And CC liked it enough to convert all their RWD platforms to it eventually. Apparently the engineers who quit over it went to work in another industry because I'd take a transverse T bar car over any other domestic front suspension of the same model year, excepting high dollar sports cars of course. In fact I'd say the MacPherson strut design is a step back, but that is fodder for another thread.

The anti-tall spindle arguments are filled with a lot of mistaken assumptions and that makes me wonder about the validity of the argument.

Posted By: origcharger

Re: Tall vs. Short Spindles - 11/07/05 03:18 AM

Quote:

Chrysler could have made the distance between the UCA and LCA inner pivots any spec they wanted,

They did have to keep adequate clearance between the upper control arm mount and the unibody "fame" rails to accomadate for the movement allowed by the K frame rubber mounting bushings, so "any spec they wanted" may be a bit of a stretch.

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/07/05 03:24 AM

That wouldn't have changed the vertical spacing between the two inner pivots. It is more likely the sheetmetal would be relocated/recontoured rather than the suspension components to make room. In fact, there is a big old access hole there to get to the inner pivot for alignment purposes so I don't think that theory holds water.

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 11/07/05 06:00 AM

There were actually no less than THREE new knuckles being designed for '73-up A, B, E, F, etc cars. ALL of those used the identical spindle design (for the unicast rotors). All that differed was the height of the knuckle's upper section and disc adapter vs. drum support mounting. It sure stands to reason that they'd want to commonize at that point if possible. Forging dies were expensive - still are!

As far as designing for the "common man", it was mentioned or implied repeatedly in earlier posts that the only one who would use the full suspension travel was exactly that person! How is a tripling of bumpsteer for Joe Average an "improvement", pray tell? A diver who sucks would surely be more freaked out (and likely to lose control) by excessive bumpsteer, it would seem to me.

Just because something works for 98% of the people who use it doesn't mean it's a good design, e.g., all those Ford Exploders you see still greasy side down, Crown Vics w/o the fuel tank ruptured, etc.

I still have not seen one post with anything approaching a logical explanation why the typical Mopar guy, who just wants to do a disc brake swap as safely and cheaply as possible, should screw up his suspension geometry.

Rick

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/07/05 06:30 AM

Quote:

You must remember the first A body came out in 1959, with the 1960 (model year) Valiant, and as far as I know the critical dimensions are the same till the end in 1976.

The 67-76 A-bodies have wider tracks. At least one of inner pickup point are moved out. Since the 60-66 cars use the same LCA's. Probably both.

Quote:

The F body came out in 1975 (1976 model year), which means that the F body should have had at least 16 years more suspension design theory and experience (including the domination of NASCAR in the 60's) than the A body. Assuming similar lead times in design and development of the two new vehicle lines. Granted the Transverse Torsion bar isn't perfect, but it did have the benefit of a lot more experience than the A body suspension did. And CC liked it enough to convert all their RWD platforms to it eventually. Apparently the engineers who quit over it went to work in another industry because I'd take a transverse T bar car over any other domestic front suspension of the same model year, excepting high dollar sports cars of course. In fact I'd say the MacPherson strut design is a step back, but that is fodder for another thread.

The anti-tall spindle arguments are filled with a lot of mistaken assumptions and that makes me wonder about the validity of the argument.

Playing arm chair quarterback trying to guess why CC engineers made each minute suspension change is pretty impossible IMHO. I bet if you interviewed everyone in the team that designed it you would get some conflicting answers even. And there has to be literally volumes of reasons.

I think this "verses" part of the discussion is played.

So....

looking at the second set of pics of Fatman spindles they look a little skimpy to me. Is it just me??

Posted By: patrick

Re: Tall vs. Short Spindles - 11/07/05 12:45 PM

Quote:

Why not LOWER the UCA mounting points to match the dimensions of the pre-iso-K cars and keep the A-body spindle?

RE: AndyF's spindle, using stock UCA's, I don't think I can tolerate a spindle that's much taller with the 5.7" BS wheels I've got. If it's possible to go significantly taller and not reduce my wheel/tire options, it would be worth it, even if it meant having to go with aftermarket UCA's. If that's not the case, I'll keep wider rubber up front and stick with the OEM spindles...

Here's another vote for the Tech Archives!

Clair

my 5th ave has the taller spindles (and yes, the horrible, death-inducing, nasty geometry bent t-bars...funny, how I can out handle most cars on the road with it), and I have about 1/2" clearance to the UBJ with 17x8 mustang wheels running a 3/4" spacer, FWIW....

Posted By: cptn60

Re: Tall vs. Short Spindles - 11/07/05 03:30 PM

Quote:

I still have not seen one post with anything approaching a logical explanation why the typical Mopar guy, who just wants to do a disc brake swap as safely and cheaply as possible, should screw up his suspension geometry.

Rick

You just wrote it yourself. All about the $s. And it isn't an unsafe swap, it's been done for years on A,B,C and E bodies for literally pennies of what a "proper" swap cost. I DO agree that with the availabilty of a repop forged knuckle, it's no longer viable. As far as the bumpsteer, in the swaps I've done; the tie rod pickup point was on the LBJ not the upright. No problem found, but I slow down for the turns, anyway.

Posted By: Clair_Davis

Re: Tall vs. Short Spindles - 11/07/05 04:43 PM

Probably hasn't been done on C's, most C-body spindles I know of are about 2" taller than an A-body spindle (I had both sitting around). Talk about making a BIG change in spindle height... Plus, the "upgrade" ABE rotors are smaller DIA than the Budd rotors on the early C's and thinner than the unicast rotors on the later C's... not much benefit to be had from that kind of swap. That said, I was recently part of a conversation with a guy who was doing just that, FJM spindles on his 68 C-body. He was in Finland, IIRC, and there wasn't much else to choose from. I think I'd keep the drums in that situation.

Clair

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/07/05 08:24 PM

Quote:

There were actually no less than THREE new knuckles being designed for '73-up A, B, E, F, etc cars. ALL of those used the identical spindle design (for the unicast rotors). All that differed was the height of the knuckle's upper section and disc adapter vs. drum support mounting. It sure stands to reason that they'd want to commonize at that point if possible. Forging dies were expensive - still are!

As far as designing for the "common man", it was mentioned or implied repeatedly in earlier posts that the only one who would use the full suspension travel was exactly that person! How is a tripling of bumpsteer for Joe Average an "improvement", pray tell? A diver who sucks would surely be more freaked out (and likely to lose control) by excessive bumpsteer, it would seem to me.

Just because something works for 98% of the people who use it doesn't mean it's a good design, e.g., all those Ford Exploders you see still greasy side down, Crown Vics w/o the fuel tank ruptured, etc.

I still have not seen one post with anything approaching a logical explanation why the typical Mopar guy, who just wants to do a disc brake swap as safely and cheaply as possible, should screw up his suspension geometry.

Rick

You are winging it aren't you?

I say that because you obviously have not looked at the toe change numbers posted earlier in the thread. The toe change at max droop is only .064", or about 1/16" more than the A spindle, hardly three times the toe change.

With the taller spindle you get more understeer than the shorter spindle. Which is EXACTLY what Joe Average needs when he thinks he's Al Unser. Guess that is why CC made the spindle taller, not because of isoclamp, transverse torsion bar or any other rabbit you can pull out of you bag of tricks.

First it was "ball joint overextended" then it was "bumpsteer" now it's "messed up geometry".

Each of your claims have been shot down by facts and hard numbers, something you haven't provided. At best you have provided hearsay evidence from unnamed sources and your "expert" opinion.

A hint for you, you can always tell when you are losing an argument when you keep changing the argument.

Posted By: origcharger

Re: Tall vs. Short Spindles - 11/07/05 08:44 PM

Quote:

That wouldn't have changed the vertical spacing between the two inner pivots. It is more likely the sheetmetal would be relocated/recontoured rather than the suspension components to make room.

Who's "winging" it here?

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/07/05 11:53 PM

Quote:

With the taller spindle you get more understeer than the shorter spindle. Which is EXACTLY what Joe Average needs when he thinks he's Al Unser. Guess that is why CC made the spindle taller, not because of isoclamp, transverse torsion bar or any other rabbit you can pull out of you bag of tricks.

Thunderstruck, do you have this backwards? I thought that the reason for going to the taller spindle (beside availability and/or price) was to promote improved handling.

The taller spindle would provide a better camber curve as the suspension is being compressed (or extended). The outside wheel on a car taking a curve will have the top of the wheel tilted inward, helping the tire to "dig in" and maintain an ideal contact patch on the pavement (and the top of inside wheel would be angled outward, also improving the contact patch).

Wouldn't this action reduce understeer, since the front tires would theoretically be gripping better?

Lawrence

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/08/05 01:50 AM

Quote:

Wouldn't this action reduce understeer, since the front tires would theoretically be gripping better?

Lawrence

Yes and No. Yes, the increased camber curve reduces understeer. But the roll center being raised reduces front roll couple (leverage between roll center and center of gravity) and that increases understeer.

So what is the overall net effect? Well, tire size will be a factor. But you'd need to skid pad test both setups. My guess, and it's a guess, is that the understeer effect from the roll center will be greater. The camber gain isn't that much and it is more of a factor at bigger amounts of roll. More understeer effect at mostly corner entry and exit. Again lots of things here, must skid pad test.

This discussion is getting into finger pointing. Trying to guess what the designers did years ago is pretty tough.

Posted By: moparx

Re: Tall vs. Short Spindles - 11/08/05 02:36 AM

nobody has yet to say how to reduce/improve bump when it's necessary

.......

Posted By: patrick

Re: Tall vs. Short Spindles - 11/08/05 02:42 AM

Quote:

Quote:

With the taller spindle you get more understeer than the shorter spindle. Which is EXACTLY what Joe Average needs when he thinks he's Al Unser. Guess that is why CC made the spindle taller, not because of isoclamp, transverse torsion bar or any other rabbit you can pull out of you bag of tricks.

Thunderstruck, do you have this backwards? I thought that the reason for going to the taller spindle (beside availability and/or price) was to promote improved handling.

The taller spindle would provide a better camber curve as the suspension is being compressed (or extended). The outside wheel on a car taking a curve will have the top of the wheel tilted inward, helping the tire to "dig in" and maintain an ideal contact patch on the pavement (and the top of inside wheel would be angled outward, also improving the contact patch).

Wouldn't this action reduce understeer, since the front tires would theoretically be gripping better?

Lawrence

Lawrence, reread what I wrote:

at full extension you have .186 degrees toe-in and at full dive, you have .013 degrees toe out. when you go around a corner, what happens? the outside wheel compresses, the inside extends. so what does this show? by reducing toe-in on the outside, and increasing it on the inside, that's effectively not steering the wheels quite as far (note, we're talking tenths of a degree), so I would assume the car would understeer slightly more. but at the same token, the higher roll center, improves roll resistance slightly, so the car should lean slightly less going around a corner, so in the end, it should pretty much be a wash.

the "increased" toe change would lead to understeer....

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 11/08/05 03:55 AM

Quote:

You are winging it aren't you?

I say that because you obviously have not looked at the toe change numbers posted earlier in the thread. The toe change at max droop is only .064", or about 1/16" more than the A spindle, hardly three times the toe change.

Huh? My calculator seems to be working fine. For the standard a-body knuckle, the toe from the MM chart changes from +0.041 to +0.122", a total bumpsteer of 0.081"

On the late B knuckle, the range given is -0.013 to +0.186, for a total bumpsteer of 0.199 inches. That's approx. 2.5 times the total bumpsteer. And it's well known that with an hour or two's tweaking, the standard knuckle's bumpsteer can be brought down much lower - I did this easily with common garage tools. From personal experience, I can state unequivocally that reduced bumpsteer is directly proportional to what most people think of as �good handling� - i.e., a car that�s easy to drive fast on public roads. Not a race car. Not a dirt track car, especially!

As I stated earlier, I did have the luxury of speaking to four of these engineers years ago. All were against this swap.

And - once again (!) I have nothing against someone making this swap, as long as they are aware of the potential ramifications. And, yes, there might be certain special applications where it might be an improvement - as was mentioned, every suspension design is a compromise on way or another. But I can't endorse it for general use. If somebody else wants to recommend it, fine. Their liability, not mine, at risk!

I don't appreciate the personal slurs. Especially from anonymous posters. Nobody knows what I'm thinking, except me. I state facts as well as my opinions, labeled clearly as such. I sign my name to all my work.

Rick

Posted By: Clair_Davis

Re: Tall vs. Short Spindles - 11/08/05 04:25 AM

Quote:

nobody has yet to say how to reduce/improve bump when it's necessary .......

Rick has published a couple articles on how to do it and when in Mopar Action over the years. I couldn't find the particular article on their web site, but you may want to poke around on it to see if it pops up for you. Google may also be your friend in this regard. If I can find the article in my back issues of MA, I'll post the nuts & bolts of the process, along with the month/year so you can get a back issue of the real deal. In typical MA fashion, the diagnosis was done with el-cheapo, home-made tools, and the fix involves a large washer, a rat-tail file, and a welder. The hardest part is probably pulling the t-bars to run the suspension through it's range of motion for the check. Fingers crossed, but maybe Rick will provide a summary, if he hasn't already done so somewhere.

Clair

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/08/05 06:05 AM

The MP Chassis manual tells you how to do it.

I wonder if the MA article is in the Tech Special CD that Rick has for sale as a banner Ad here on Moparts??

Quote:

nobody has yet to say how to reduce/improve bump when it's necessary .......

The tough part is the "when it's necessary" part. I've heard tons of people on this site toss the term bump steer at car that just needed shocks, regular alignments, replaced suspension componets, etc etc.

Just because your car wonders when you drive over ruts on the road does not mean it needs bumpsteer fixed. IMHO, 50% of the time it needs an idler and/or an alignment.

Posted By: cptn60

Re: Tall vs. Short Spindles - 11/08/05 06:25 AM

Rick, first off let me say that I can respect your opinions, based on your real world experience. I can also say that I've performed this swap on 2 68-70b's, and 1 e body. I saw no ill handling in the cars, but I didn't autocross, solo or anything of the sort. With all the wildlife around here(deer,turkeys, drunks from the lake) braking advantages were of primary importance in my case. And this swap excels in this matter.

Posted By: bull

Re: Tall vs. Short Spindles - 11/08/05 10:20 AM

I'm late to the party here but I have a question for Mr. Ehrenberg regarding something he mentioned here and in his Disc-o-Tech article. You say we should avoid swapping the spindles from side to side to avoid sway bar interference but do you say that only for the sake of the brake line routing issues or are there any other issues you see? Are they virtually interchangeable otherwise? I did happen to discover on my own that the 1980 St. Regis brake hoses (Napa PN 4136828) are the right length and seem to route well for the configuration with the spindles swapped side to side. Of course my clearance tests have only been done with the car on jack stands, not on the road.

I'm not savvy enough on engineering and geometry to comment one way or the other on the spindles (I did choose to use 1974 Dart spindles on my Charger) but my decision to follow the advice in Ehrenberg's article was based on the fact that there isn't really any definitive information on the taller spindles to warrant my using them. Just the fact that there's all this debate is enough to cause me to play it safe. There are still lots of A-body spindles out there to be had (although the supply is drying up fast) as well as the MP Brakes spindles. And then there's always Wilwood, SSBC, Baer and the Viper kits, so why take a chance? The Wilwood kits are priced low enough now that they're only about $200 more than I paid for my wrecking yard kit so the price isn't really an issue anymore.

Anyway, just my

Notice how I heed his advice on the spindle height but ignore his advice on swapping them side to side.

Posted By: bull

Re: Tall vs. Short Spindles - 11/08/05 10:53 AM

By the way, here's my parts list if anyone cares. Might be helpful to someone who's still looking for parts.

My �brake� down

2 Spindles: 1974 Dart (used) $90
2 Caliper adapters: 1977 Fury pin style (used) $36 incl. shipping
2 Rotors: 1977 Fury (new) $91.21
2 Calipers: 1973 Challenger (rebuilt) Loaded with new semi-metallic pads, pin fastener set, etc. $129.98
1 Disc Brake Master cylinder: 1973-1980s Dodge truck (rebuilt) $28.76 (This will be replaced by one that looks correct)
2 Hoses: 1980 St. Regis (new) $30.98
2 Oil seals: 1977 Fury (new) $3.49
2 Outer wheel bearings: 1977 Fury (new) $8.50
2 Inner wheel bearings: 1977 Fury (new) $11.18
1 Wilwood Proportioning Valve: $42.50
1 Wilwood Residual Pressure Valve: $16.46
Misc.: $15

Total: $504.06

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 11/08/05 01:04 PM

Quote:

You say we should avoid swapping the spindles from side to side to avoid sway bar interference but do you say that only for the sake of the brake line routing issues or are there any other issues you see? Are they virtually interchangeable otherwise?

Yes, the brake flex-hose is my worry. As long as you carefully check for interference and the hose going taut, at all combinations of full lock left and right, and full jounce to full rebound, as well as checking for potential abrasion spots, go for it. Also be sure the bleeder screws are on top!

On the bump-steer correction: I agree 100% that this would NOT be the first thing to check if a car has a suspension / handling / steering problem! Only if a car that's freshly assembled (esp. a K-member swap) and aligned has handling ills - esp. a steering-wander-type symptom on rural roads - would I begin to worry about bumpsteer. If the car is assembled as designed this should not be an issue. of course, if you're a perfectionist, having added, say, Koni shocks, big tie-rods, firm-feel / fast-ratio steering, etc., you might want to check it anyway. Back in the '60s, some of these cars were very precise and easy to drive fast, like good 2005 car. Some were only "OK". I suspect that bumpsteer may have been the difference.

As far as corrections, as has been mentioned several times above, the MP chassis book has what is basically reprints of some old Chrylser Master Tech books, which give detailed instructions on corrections. I may have written something on this in the past, too, yes, check those old tech special issues being sold by Coltrane.

Rick

Posted By: Rick_Ehrenberg

Re: Tall vs. Short Spindles - 11/08/05 01:08 PM

Quote:

...The hardest part is probably pulling the t-bars to run the suspension through it's range of motion for the check.

No need for that! Just back the adjuster off completely.

Rick

Posted By: 69 Road Runner

Re: Tall vs. Short Spindles - 11/08/05 01:13 PM

Quote:

By the way, here's my parts list if anyone cares. Might be helpful to someone who's still looking for parts.

My �brake� down

2 Spindles: 1974 Dart (used) $90
2 Caliper adapters: 1977 Fury pin style (used) $36 incl. shipping
2 Rotors: 1977 Fury (new) $91.21
2 Calipers: 1973 Challenger (rebuilt) Loaded with new semi-metallic pads, pin fastener set, etc. $129.98
1 Disc Brake Master cylinder: 1973-1980s Dodge truck (rebuilt) $28.76 (This will be replaced by one that looks correct)
2 Hoses: 1980 St. Regis (new) $30.98
2 Oil seals: 1977 Fury (new) $3.49
2 Outer wheel bearings: 1977 Fury (new) $8.50
2 Inner wheel bearings: 1977 Fury (new) $11.18
1 Wilwood Proportioning Valve: $42.50
1 Wilwood Residual Pressure Valve: $16.46
Misc.: $15

Total: $504.06

Did you front or rear mount your calipers? I want to rear mount my calipers to clear the factory sway bar on my 69 Road Runner. If I can get the hoses at the parts store instead of ordering them, that would make things easier, particularly if they have to be returned.

Posted By: Montclaire

Re: Tall vs. Short Spindles - 11/08/05 01:43 PM

I have the bumpsteer article, I'll scan it later on and post it. Good ol' backyard tech at it's finest. Been covered at least twice in Mopar Action; yet another reason to get a subscription.

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/08/05 03:37 PM

Thing about bumpsteer is that you do not change spindle height to fix it. Regardless of what spindle you run, because spindle hieght doesn't cause bumpsteer, though it might accentuate it.

You fix bumpsteer by changing the location of the tie rodd pivot points, inner or outer depending on what you have for bumpsteer. Since the tie rod pivot points never change when you swap out the spindles I find it real hard to accept the claim that a taller spindle causes it.

About the UCA mount being wrapped arouns the frame rail on Isoclamp cars, true, BUT you are thinking one dimensionally, you could raise the LCA pivot point to acquire the same vertical spacing if it was so important to do so. I assume the factory engineers would have done that if need be.

Posted By: origcharger

Re: Tall vs. Short Spindles - 11/08/05 05:05 PM

Quote:

About the UCA mount being wrapped arouns the frame rail on Isoclamp cars, true, BUT you are thinking one dimensionally, you could raise the LCA pivot point to acquire the same vertical spacing if it was so important to do so. I assume the factory engineers would have done that if need be.

True they could raise it, but my point all along was that they could not LOWER it, if needed, to achieve the same vertical spacing, which could be why there was a need for a taller spindle when the B bodies went to the rubber isolated front suspension.

Posted By: cptn60

Re: Tall vs. Short Spindles - 11/08/05 07:01 PM

Quote:

Thing about bumpsteer is that you do not change spindle height to fix it. Regardless of what spindle you run, because spindle hieght doesn't cause bumpsteer, though it might accentuate it.

You fix bumpsteer by changing the location of the tie rodd pivot points, inner or outer depending on what you have for bumpsteer. Since the tie rod pivot points never change when you swap out the spindles I find it real hard to accept the claim that a taller spindle causes it.

Bingo!! It takes a texan

Posted By: bull

Re: Tall vs. Short Spindles - 11/08/05 08:20 PM

Quote:

Quote:

By the way, here's my parts list if anyone cares. Might be helpful to someone who's still looking for parts.

My �brake� down

2 Spindles: 1974 Dart (used) $90
2 Caliper adapters: 1977 Fury pin style (used) $36 incl. shipping
2 Rotors: 1977 Fury (new) $91.21
2 Calipers: 1973 Challenger (rebuilt) Loaded with new semi-metallic pads, pin fastener set, etc. $129.98
1 Disc Brake Master cylinder: 1973-1980s Dodge truck (rebuilt) $28.76 (This will be replaced by one that looks correct)
2 Hoses: 1980 St. Regis (new) $30.98
2 Oil seals: 1977 Fury (new) $3.49
2 Outer wheel bearings: 1977 Fury (new) $8.50
2 Inner wheel bearings: 1977 Fury (new) $11.18
1 Wilwood Proportioning Valve: $42.50
1 Wilwood Residual Pressure Valve: $16.46
Misc.: $15

Total: $504.06

Did you front or rear mount your calipers? I want to rear mount my calipers to clear the factory sway bar on my 69 Road Runner. If I can get the hoses at the parts store instead of ordering them, that would make things easier, particularly if they have to be returned.

I rear mounted them to avoid swaybar interferance. Just be careful with your brake hoses as Rick says above. Some people have had the hoses custom made but I seem to have found a good match with those St. Regis hoses, and they're only $30 and change per pair.

Posted By: 69 Road Runner

Re: Tall vs. Short Spindles - 11/08/05 08:23 PM

Quote:

I rear mounted them to avoid swaybar interferance. Just be careful with your brake hoses as Rick says above. Some people have had the hoses custom made but I seem to have found a good match with those St. Regis hoses, and they're only $30 and change per pair.

Do you have any pictures?

Posted By: Anonymous

Re: Tall vs. Short Spindles - 11/09/05 07:03 AM

adding more

say I change my 70 duster to the tall spindle w/ matching discs and bracket, caliper, etc. after changing the UCA to newer Large UBJ. Would this spindle at http://www.piratejack.net/spindle.html
fit if I wanted to restore my original suspension geometry?

Posted By: NJK66

Re: Tall vs. Short Spindles - 11/14/05 04:11 PM

Near as I can see it will. There will just be some geometry changes that if you read this whole posting, is what all the debate regarding the tall vs. short spindle is about. As near as I can see the front end will align to factory specifications. You gain a bit of positive caster which I understand is a plus but you raise the roll center of the vehice which I am not sure if this is good or bad. Depends on who you talk to. The taller spindle is 3/8 inch taller than the one you have on your car. I am going to try to use the stock upper control arms with the taller spindle but I am going to make sure I have ample travel of the upper control arm (potential bind). If I have any reservations regarding how my car feels or steers, I'm going to buy the Firm Feel UCA's.

BTW there is some really good info in this posting does anyone know how to get it in the tech archives?

Posted By: Montclaire

Re: Tall vs. Short Spindles - 02/20/07 12:05 AM

I'm bumping this for preservation, seeing how many posts I've seen on this lately. I don't want to get it going again, just put it out there for people to read. Lots of good info, on both sides of the issue. Archives? Please?

Posted By: 71charger

Re: Tall vs. Short Spindles - 11/26/07 04:17 AM

Bump, as it seems this wheel is being reinvented yet again.

https://board.moparts.org/ubbthreads/show...;gonew=1#UNREAD

Posted By: rtidd440

Re: Tall vs. Short Spindles - 11/26/07 05:13 AM

I'm a little late to this party but I have a question for Rick. If using the taller spindles raises the ball joint end of the upper arm in relation to the pivot point of the arm, could you use the moog offset bushings to raise the rear of the arm 3/8 to compensate? If so would that make the geometry acceptable? I believe there would still be a difference in the roll center but would all else be ok?

Posted By: autoxcuda

Re: Tall vs. Short Spindles - 11/26/07 06:23 AM

Quote:

... If using the taller spindles raises the ball joint end of the upper arm in relation to the pivot point of the arm, could you use the moog offset bushings to raise the rear of the arm 3/8 to compensate? If so would that make the geometry acceptable? I believe there would still be a difference in the roll center but would all else be ok?

The factory alignment eccentrics themselves allow for 3/8" of movement up/down/in/out in the upper control arm inner pickup point. When you adjust your alignment the roll center is changing. Very few of these cars on the road will have the same exact roll centers.

If you installed the offset 7103 UCA bushings to move the UCA chassis pickup point up, the ball joint angle and a-arm angle will be closer to stock. But the roll center still will not be the same exact place as with the shorter spindle.

The newer ball joints take a little more angle than stock OE NOS. And the lower control arm will have to smash through the frame an INCH or TWO to make the ball joint start to lock up.