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TR6 TR6 Squat Up-date

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jerrybny

jerrybny

Jedi Knight
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TR6 Squat Update

Well, some of you may remember that I posted that my 73 TR6 was squatting. Well I ordered the GoodParts brackets and springs. I did the driver side last nite and today. I can't believe I didn't run into any problems. Everything came apart without any swearing. Same thing with installing the new parts. The only thing is thay goodparts didn't include any instructions for adjusting the camber. If anyone has these brackets and could send me some instructions for adjusting the camber I would appreciate it. Next weekend I plan to do the passenger side. Thank You.

jbrawner@hvc.rr.com
 
Re: TR6 Squat Update

You did better than me then. I was swearing fer sure the whole time trying to unfasten the last nut on the trailing arm. You know the one - it's the one that welded itself in place and you can't get a socket on it because the frame is in the way.

I thought to adjust the camber you loosened the horizontal bolt and turned the vertical bolt. I seem to remember that 1 turn was 1/4 of a degree. I'll look tomorrow and see if I can find the exact words. I think 50ft/lb was the magic # for retightening too.


Congrats btw. Wish mine had been that easy /ubbthreads/images/graemlins/wink.gif
 
Re: TR6 Squat Update

Jerry,

Since you are online I shuffled out to the garage and grabbed the sheet. This is what I have - and I quote:

To adjust the camber, raise and support the car then loosen both fulcrum bolts. Turn the adjuster bolts to raise or lower the fulcrum as needed taking care that the fulcrum bolt does not bind in the slot. The spring tension is pushing down on the front of the trailing arm and can cause the pivot bolt to slide down and bind when you try to turn the adjuster. Hook up a screwdriver or prybar on top of the head of the lower bolt holding the bracket to the frame and pry up on the end of the trailing arm to release the tension as you turn the adjuster. Use the same prying method to relieve the downward tension and level the pivot bolt as you retorque it. One turn on the adjuster bolt will change the camber approximately 1/4 degree. Turning clockwise on the outer adjuster bolt of the inner bracket will lower the inner fulcrum and tilt the top of the tire to increase negative camber. Turning couter clockwise on the outer adjuster will raise the outer fulcrum and also increase negative camber. Turning counter clockwise on the inner and outer will tilt the top of the tire out to reduce negative camber. Raising both inner and outer fulcrums will not change camber but will raise ride height slightly.

This is a quick copy. Spelling mistakes are mine.
Hope it helps.
 
Re: TR6 Squat Update

My pleasure. Hope it helps.
fwiw, mine was pretty much spot on unadjusted from the box. I used his springs and so lowered it too though, but given the t/arm design I can't see how lowering affects camber.
 
Re: TR6 Squat Update

Hi alana,
Changing the spring length affects the camber because of the rear suspension's geometry. The fulcrum of the trailing arm is not parallel to the centerline of the hub but rather at an angle. When the suspension is acted upon (hitting a bump or a rut) the trailing arm travels in an arc around the fulcrum. If the suspension were to travel to it's uppermost position you would see that the top of the tire has moved toward the centerline of the car. At the lowest position the bottom of the tire moves to the center. This type of suspension also afects the toe at the same time. When the trailing arm moves up the toe in increases, down and the toe goes out.
When a shorter spring is installed it is as if you have hit a permanant bump and have added negative camber and increased toe in slightly.
Hope this explains how shorter springs increase negative camber.
BTW I too installed Richard Good's brackets and I think there great! No more squat! /ubbthreads/images/graemlins/grin.gif
 
Re: TR6 Squat Update

I must be having a brain fart because I'm still not getting the mental picture here. I don't 'see' how rotation in one axis can affect another at right angles to it all else being equal. Even if the axis of rotation was skewed I'd think that the offset (camber here) would be constant since we have fixed length objects rotating round a fixed pivot point.

I'm gonna have to take the wheel off now or it will drive me nuts...
 
Re: TR6 Squat Update

Alan,
What you have to keep in mind in this situation is the position of the hub face or the face of the brake drum as the trailing arm rotates about it's fulcrum. Look at it this way, if the trailing arm were a "A" arm with the pivot at a right angle to the hub and the hub fixed to the arm. When the arm is rotated the hub face remains tangent to the arc of travel thus exagerating the effect on camber. Now when the axis of rotation is shifted from this point to anything short of 90 deg the hub face still remains tangent to the arc of rotation but since the hub is no longer parallel to the axis of rotation the effect is to minimize the change in camber. When the axis of the arm's rotation is set perpendicullar to the hub (read in front of the axle) the effect would be that there would be no change in camber but there would be a shortening of the wheel base when the suspension is acted upon.
[ QUOTE ]
Even if the axis of rotation was skewed I'd think that the offset (camber here) would be constant since we have fixed length objects rotating round a fixed pivot point.

[/ QUOTE ]
Not exactly, since the the trailing arm is a fixed length and the hub is fixed to it, the two parts travel together.
The camber is directly proportional to the amount of rotation of the arm. If the hub were independant of the swing arm as in a multi link set up then the travel of the hub would remain perpendicular to the ground.
I'm sorry if my explanation is not the clearest. I hope that I haven't confused you even more. It may be helpful to make a small model of the suspension out of a small dowel rod and some cardboard to help visualize the motion. Also, exagerate the amount of travel, this should make it clearer to see since on the car the actual changes are small only a degree or two. /ubbthreads/images/graemlins/smile.gif
 
Re: TR6 Squat Update

Got it.
I was just having a "senior moment" for some reason.

Thanks.
 
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