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Re: Tall vs. Short Spindles
[Re: Rick_Ehrenberg]
#17912
11/07/05 04:24 PM
11/07/05 04:24 PM
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Anonymous
Unregistered
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Anonymous
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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.
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Re: Tall vs. Short Spindles
[Re: origcharger]
#17914
11/07/05 06:37 PM
11/07/05 06:37 PM
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Anonymous
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Anonymous
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Quote:
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?
You.
have you ever spent any time looking at it?
The claim that the UCA would interfere with the sheetmetal was a WAG by someone. Anyone who has ever pulled the access plate off would see there is not sheetmetal to interfer with anything on a transverse setup. And the late B setup's I have seen are similar. Which proves the statement I made that the sheetmetal would be odified to cear and not the UCA mounting location.
You ever look at that in an F/J/M or later B or ANY isoclamp car?
Nope, didn't think so.
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Re: Tall vs. Short Spindles
#17915
11/07/05 07:53 PM
11/07/05 07:53 PM
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Anonymous
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Anonymous
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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
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Re: Tall vs. Short Spindles
#17916
11/07/05 09:16 PM
11/07/05 09:16 PM
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Joined: Jan 2003
Posts: 4,062
Fort DODGE, Ioway
origcharger
master
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master
Joined: Jan 2003
Posts: 4,062
Fort DODGE, Ioway
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Quote:
Quote:
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?
You.
have you ever spent any time looking at it?
The claim that the UCA would interfere with the sheetmetal was a WAG by someone. Anyone who has ever pulled the access plate off would see there is not sheetmetal to interfer with anything on a transverse setup. And the late B setup's I have seen are similar. Which proves the statement I made that the sheetmetal would be odified to cear and not the UCA mounting location.
You ever look at that in an F/J/M or later B or ANY isoclamp car?
Nope, didn't think so.
The upper control arm mounts on both my 76 Cordoba and 79 Newport curls up and over the top of the unit body frame rail. The way it is designed there is no way to make it any lower and keep the clearance necessary to allow the rubber isolated suspension to work.
"Which proves the statement I made that the sheetmetal would be odified to cear and not the UCA mounting location."
Sounds like you are still winging it.
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Re: Tall vs. Short Spindles
#17917
11/07/05 09:50 PM
11/07/05 09:50 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:
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.
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Re: Tall vs. Short Spindles
#17919
11/07/05 10:42 PM
11/07/05 10:42 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:
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....
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
#17920
11/07/05 11:55 PM
11/07/05 11:55 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:
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
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Re: Tall vs. Short Spindles
[Re: moparx]
#17921
11/08/05 12:25 AM
11/08/05 12:25 AM
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Joined: Feb 2003
Posts: 4,204
Fort Worth, TX
Clair_Davis
master
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master
Joined: Feb 2003
Posts: 4,204
Fort Worth, TX
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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
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Re: Tall vs. Short Spindles
[Re: Rick_Ehrenberg]
#17923
11/08/05 02:25 AM
11/08/05 02:25 AM
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Joined: Feb 2003
Posts: 1,095
Bloomington, Illernoise
cptn60
super stock
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super stock
Joined: Feb 2003
Posts: 1,095
Bloomington, Illernoise
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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.
This space available for rent
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Re: Tall vs. Short Spindles
[Re: cptn60]
#17924
11/08/05 06:20 AM
11/08/05 06:20 AM
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Joined: Oct 2003
Posts: 403
Western Oregon
bull
mopar
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mopar
Joined: Oct 2003
Posts: 403
Western Oregon
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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. 
1968 Charger 383/2bbl/4spd (1 of 74)
1994 Dakota Sport 3.9L/AT/2WD
2003 Durango SLT 4.7L/AT/4X4
Yes, all Dodges and nothing else
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Re: Tall vs. Short Spindles
[Re: bull]
#17925
11/08/05 06:53 AM
11/08/05 06:53 AM
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Joined: Oct 2003
Posts: 403
Western Oregon
bull
mopar
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mopar
Joined: Oct 2003
Posts: 403
Western Oregon
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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
1968 Charger 383/2bbl/4spd (1 of 74)
1994 Dakota Sport 3.9L/AT/2WD
2003 Durango SLT 4.7L/AT/4X4
Yes, all Dodges and nothing else
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Re: Tall vs. Short Spindles
[Re: bull]
#17926
11/08/05 09:04 AM
11/08/05 09:04 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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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
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Re: Tall vs. Short Spindles
[Re: Clair_Davis]
#17927
11/08/05 09:08 AM
11/08/05 09:08 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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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
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Re: Tall vs. Short Spindles
[Re: Montclaire]
#17930
11/08/05 11:37 AM
11/08/05 11:37 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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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.
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Re: Tall vs. Short Spindles
#17931
11/08/05 01:05 PM
11/08/05 01:05 PM
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Joined: Jan 2003
Posts: 4,062
Fort DODGE, Ioway
origcharger
master
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master
Joined: Jan 2003
Posts: 4,062
Fort DODGE, Ioway
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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.
MOPARTS ALERT!: Chris Pugh aka gabodyman of Dalton, Georgia, cashed my $140 money order on 4-16-02 never sent parts. On 3-19-07 he agreed to return my money; "april 9, it will be in the mail by that date""will do as promised. chris" Still no parts and no money!
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