upper control arm offset cross shaft, which way
Thread Starter
Racer
Joined: Apr 2001
Posts: 391
Likes: 1
From: Bend, Oregon
upper control arm offset cross shaft, which way
I am installing offset upper control arm cross shafts in my 74 along with all the other poly stuff from the super front end kit. My question is which way should the off set be, to the inside (making the top of the wheel more towards the inside) or to the outside, cambering the top of the wheel out. I have them in the car now to compensate for the shims that were in the orginal shaft. It will still take a shim or two but not the 4 that were in there. This seems to make sense to me, but I do not know for sure. Thanks in advance........
Garson
Garson
Le Mans Master
Joined: Mar 2004
Posts: 7,499
Likes: 1,507
From: Little Rock AR
The off-set upper control arm shafts are handy on old Camaros because you can use them to push the top of the wheel out. This helps because those cars frequently have the frames pushed in after all these years of hard use and spirited driving. The frame rails bend inward so the alignment goes out of whack. You can compensate for it by removing shims to get the wheels back where they belong but once you take all the shims out, you are done. Using the off-set shaft can push the top A-frame out far enough so you can put some shims back in there and gain some adjustability. That is what I would do with them. Adding shims is easy with either straight or off-set shafts but you can only take away just so much with a straight shaft.
Hope this helps,
-Mark.
Hope this helps,
-Mark.
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Having negative camber - tops of tires leaning in / \ helps with straight line stability & aids in steering wheel returnability. Positive camber \ / sometimes aids in cornering, but will make the front wander at speeds.
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
INBOARD! The shims bring the cross shaft inboard, if you want to run fewer shims with the offset shafts you need the offset inboard to take the spacing the shims gave. If you want to gain adjustabillity with using a lot of shims (as in having a lot of sweep to be able to adjust over) then outboard. I'm not a fan of lots of shims, I would use them inboard but it does take away from the max. of pos. camber you will be able to set.
Drifting
Joined: Sep 1999
Posts: 1,411
Likes: 1
From: Wylie TX
Originally Posted by 71coupe
Having negative camber - tops of tires leaning in / \ helps with straight line stability & aids in steering wheel returnability. Positive camber \ / sometimes aids in cornering, but will make the front wander at speeds.
Having some negative camber aids in cornering since it allows more tread to grip the road on the loaded wheel in a turn.
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Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Originally Posted by Twin_Turbo
INBOARD! The shims bring the cross shaft inboard, if you want to run fewer shims with the offset shafts you need the offset inboard to take the spacing the shims gave. If you want to gain adjustabillity with using a lot of shims (as in having a lot of sweep to be able to adjust over) then outboard. I'm not a fan of lots of shims, I would use them inboard but it does take away from the max. of pos. camber you will be able to set.
If you are trying to eliminate all those shims then you turn the offset crosshaft in the direction that would eliminate the shims.
Old specs called for positive camber. The more modern specs call for negative.
I personally don't like the looks of negative 3/4 camber. The wheels look like they are caving in. Right now I run zero. Wheels straight up and down front and back.
Negative improves cornering, just liking gaining camber on cornering.
Look at the cross shafts and visuilize what you are trying to do. Turn them one way and it moves the A arms out, do you want this? Why all the shims? Are you not trying to move the A arm in? Then turn the new offset cross shafts so they push the A arm in, like adding shims to the old setup.
Really it is not hard if you just hold the cross shaft in position and visualize what it will do in the different positions.
Instructor
Joined: Nov 2004
Posts: 194
Likes: 0
From: Appleton Wi.
You can turn them which ever way to suite your purpose. I put one on facing out and the other facing in. That was to compensate for a slight tweak from previous owner. But, it worked great. I now have enough adjustability.
TJ
TJ
Racer
Joined: Nov 2003
Posts: 281
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From: Altoona pa
the tech guy at vbp told me if you have a large shim stack to face the offset to the outside of the car. i think. he also said if i was wrong the guy that did the alignment would do what he needed to do whe n he alighned the car.
Race Director
Joined: Dec 1999
Posts: 16,945
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if the vbp tech said that he is wrong, think about it, turning the shaft outboard will bring the bushing center outboard even more, so if you want neg. camber to stay the same you have to shim up the shafts even more to get the correct setting.
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Originally Posted by Twin_Turbo
if the vbp tech said that he is wrong, think about it, turning the shaft outboard will bring the bushing center outboard even more, so if you want neg. camber to stay the same you have to shim up the shafts even more to get the correct setting.
Twin Turbo is right. I really can't see where the problem is here. If you are trying to eliminate a thick shim pack you turn the offset in to pull the upper a arm in at the same time eliminating the shims.
