Need bump steer expert advice
05-22-2011, 10:01 PM
#1
Race Director
Thread Starter
Need bump steer expert advice
Please post only if you have actually adjusted for bump steer yourself.
I have the Baer kit & the instructions say that bump steer is caused by BOTH lowering AND adding negative camber.
I thought it was just lowering.
I was going to approximate the shimming based on the amount of lowering I had both ends, but now I am not sure that'll come out right as I also have added neg. camber both ends.
I do not have an alignment rack & means to compress the suspension while measuring toe and there is no shop (that I personally trust) that is capable of this where I live.
Suggestions? There should be a way to calc it and get pretty close or at least improve & move the alignments back towards ideal.
Thanks.
I have the Baer kit & the instructions say that bump steer is caused by BOTH lowering AND adding negative camber.
I thought it was just lowering.
I was going to approximate the shimming based on the amount of lowering I had both ends, but now I am not sure that'll come out right as I also have added neg. camber both ends.
I do not have an alignment rack & means to compress the suspension while measuring toe and there is no shop (that I personally trust) that is capable of this where I live.
Suggestions? There should be a way to calc it and get pretty close or at least improve & move the alignments back towards ideal.
Thanks.
05-22-2011, 10:32 PM
#2
Typically caster affects bumpsteer more so than camber.
To correctly adjust for bumpsteer you must remove the spring and cycle the suspension. Compression is more important than droop. Furthermore, I'd say focus on the first inch more so than beyond that. There is really no way to get it dialed in without actually measuring it.
Set the toe you want at the ride height you want with your desired alignment. Pull spring(s), check/adjust bumpsteer. Re-set toe.
It can be time consuming.
The way I mimic ride height when up on jack stands is to use an angle finder on either the upper or lower control arm. With fenders on, the lower is used. Place a jack under the suspension and lift it up(no spring) until the reading is the same as when the car is on level ground with the correct ride height. That is assuming the jackstands are holding the car pretty level.
If you can't do all that right away all you can do is try and get the steering arm/tie rod to run parallel with an imaginary line drawn between the lower control arm pivot point on the chassis and the centerline of the balljoint.
To correctly adjust for bumpsteer you must remove the spring and cycle the suspension. Compression is more important than droop. Furthermore, I'd say focus on the first inch more so than beyond that. There is really no way to get it dialed in without actually measuring it.
Set the toe you want at the ride height you want with your desired alignment. Pull spring(s), check/adjust bumpsteer. Re-set toe.
It can be time consuming.
The way I mimic ride height when up on jack stands is to use an angle finder on either the upper or lower control arm. With fenders on, the lower is used. Place a jack under the suspension and lift it up(no spring) until the reading is the same as when the car is on level ground with the correct ride height. That is assuming the jackstands are holding the car pretty level.
If you can't do all that right away all you can do is try and get the steering arm/tie rod to run parallel with an imaginary line drawn between the lower control arm pivot point on the chassis and the centerline of the balljoint.
05-22-2011, 10:56 PM
#3
Typically caster affects bumpsteer more so than camber.
To correctly adjust for bumpsteer you must remove the spring and cycle the suspension. Compression is more important than droop. Furthermore, I'd say focus on the first inch more so than beyond that. There is really no way to get it dialed in without actually measuring it.
Set the toe you want at the ride height you want with your desired alignment. Pull spring(s), check/adjust bumpsteer. Re-set toe.
It can be time consuming.
The way I mimic ride height when up on jack stands is to use an angle finder on either the upper or lower control arm. With fenders on, the lower is used. Place a jack under the suspension and lift it up(no spring) until the reading is the same as when the car is on level ground with the correct ride height. That is assuming the jackstands are holding the car pretty level.
If you can't do all that right away all you can do is try and get the steering arm/tie rod to run parallel with an imaginary line drawn between the lower control arm pivot point on the chassis and the centerline of the balljoint.
To correctly adjust for bumpsteer you must remove the spring and cycle the suspension. Compression is more important than droop. Furthermore, I'd say focus on the first inch more so than beyond that. There is really no way to get it dialed in without actually measuring it.
Set the toe you want at the ride height you want with your desired alignment. Pull spring(s), check/adjust bumpsteer. Re-set toe.
It can be time consuming.
The way I mimic ride height when up on jack stands is to use an angle finder on either the upper or lower control arm. With fenders on, the lower is used. Place a jack under the suspension and lift it up(no spring) until the reading is the same as when the car is on level ground with the correct ride height. That is assuming the jackstands are holding the car pretty level.
If you can't do all that right away all you can do is try and get the steering arm/tie rod to run parallel with an imaginary line drawn between the lower control arm pivot point on the chassis and the centerline of the balljoint.
05-22-2011, 11:37 PM
#4
Race Director
Thread Starter
Thanks guys, I am really not going to pull the springs, I don't have the shop to do it. I have pulled them on my c4 so I know what a job that is just using floor jacks etc.
I know there's the "right way" to do it, but I think if I get close it'll be better than nothing.
I do my own alignment so I will proceed that way, I am pretty sure that any bump steer I have introduced with the height/alignment changes is not huge as the car still handles well & I get good results in competition.
Putting everything all parallel may be the best I can do.
I know there's the "right way" to do it, but I think if I get close it'll be better than nothing.
I do my own alignment so I will proceed that way, I am pretty sure that any bump steer I have introduced with the height/alignment changes is not huge as the car still handles well & I get good results in competition.
Putting everything all parallel may be the best I can do.