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Re: Tall vs. Short Spindles
[Re: DJVCuda]
#17872
11/02/05 02:02 PM
11/02/05 02:02 PM
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Joined: Sep 2003
Posts: 1,688
Marlboro, NY, USA
Rick_Ehrenberg
top fuel
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top fuel
Joined: Sep 2003
Posts: 1,688
Marlboro, NY, USA
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Quote:
It sounds like somebody needs to take the time to make the measurements to put this matter to rest.
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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:
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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
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Re: Tall vs. Short Spindles
[Re: Rick_Ehrenberg]
#17873
11/02/05 02:46 PM
11/02/05 02:46 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
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!
Rick- the guy who did the measurements was respected suspension builder Bill Rielly, who produces and markets the AlterKtion front suspension setup....I wouldn't consider him some back yard bubba when it comes to front suspensions...
also, the 3/8" height difference, assuming a 10" UCA (not sure what the actual pivot-to-ball-joint center distance is on the A or B/E arms are, but it's gotta be close to that) is only a 2 degree difference with all else the same. and you can get that much vertical movement in the adjustment of the UCA as it is. on these spindles, the steering arm to LBJ/spindle centerline relationship is identical to the early A/B/E spindle. the toe change isn't that huge, and as the article states, that's with the suspension fully extended, which will only happen if you're trying to recreate the "bullit" chase scene in a car with no sway bars...granted they do have an additional .5 degree SAI, but that actually improves self centering...if you're that concerned about using them, couldn't you use the offset bushings installed 90 degrees from intended to raise the control arm up?
the full article that Bill did that was in MM is here:
url=http://www.bigblockdart.com/tech/spindles.shtml]bigblockdart.com spindle article.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Tall vs. Short Spindles
[Re: NJK66]
#17876
11/02/05 03:12 PM
11/02/05 03:12 PM
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Joined: Aug 2003
Posts: 11,179
Atco NJ
DJVCuda
I Live Here
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I Live Here
Joined: Aug 2003
Posts: 11,179
Atco NJ
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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....
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Re: Tall vs. Short Spindles
[Re: NJK66]
#17877
11/02/05 04:42 PM
11/02/05 04:42 PM
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Joined: Jan 2003
Posts: 2,016
Frederick, MD
71charger
top fuel
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top fuel
Joined: Jan 2003
Posts: 2,016
Frederick, MD
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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.
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Re: Tall vs. Short Spindles
[Re: Rick_Ehrenberg]
#17883
11/02/05 10:45 PM
11/02/05 10:45 PM
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Joined: Jan 2003
Posts: 27,485
So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,485
So Cal
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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.
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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.
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Re: Tall vs. Short Spindles
[Re: BergmanAutoCraft]
#17886
11/03/05 12:18 AM
11/03/05 12:18 AM
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Joined: Jan 2003
Posts: 27,485
So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,485
So Cal
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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.
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Re: Tall vs. Short Spindles
[Re: BergmanAutoCraft]
#17888
11/03/05 10:42 AM
11/03/05 10:42 AM
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Joined: Sep 2003
Posts: 1,688
Marlboro, NY, USA
Rick_Ehrenberg
top fuel
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top fuel
Joined: Sep 2003
Posts: 1,688
Marlboro, NY, USA
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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 Volaré 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
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Re: Tall vs. Short Spindles
[Re: moparx]
#17890
11/03/05 11:23 PM
11/03/05 11:23 PM
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Joined: Sep 2003
Posts: 1,688
Marlboro, NY, USA
Rick_Ehrenberg
top fuel
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top fuel
Joined: Sep 2003
Posts: 1,688
Marlboro, NY, USA
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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
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Re: Tall vs. Short Spindles
[Re: Rick_Ehrenberg]
#17891
11/04/05 12:39 AM
11/04/05 12:39 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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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.
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