youngcow

Hey all,

I been trying to figure out this problem for almost a year now. Last May I installed EVS rear toe arms, Blox front 12mm Bumpsteer kit, and raised my car half an inch. When I hit bumps on my left side the car jerks. If I make a left turn over a bump or a hard left the steering will change in the weight not the input, and when I straighten out I get the same jerk as if it's going back to it's original alignment. Bumps on the right side does not affect the car at all.

I then removed the bumpsteer kit, the bumpsteer jerk felt a little better after an alignment but still have noticeable bumpsteer. The steering wheel, when turning left would straighten out, but if I turned right the steering wheel would be off to the right a little bit.

I was able to narrow it down to the Lower ball joints, and replaced those with J's Racing sp1. After an alignment the steering wheel would steer straight and not change, but while driving straight the steering wheel is still off to the right. There's still minor bumpsteer/jerking motion on the driverside when I go over bumps, but no bumpsteer over potholes.

In case anyone is wondering, I have SPC ball joints on all 4 corners, -2 front -2.5 rear camber, 6.4 Caster, .28 rear toe in .57 total rear toe, 0.0 front toe.

If anyone could provide ideas, suggestions or any kind of help that would be awesome. I been racking my brain on this since May of last year. My next guess is front end tie rods. I have Wicked Tuning tie rods I was thinking about installing but not too sure yet.

Thanks,

Young

Slowcrash_101

I suspect your bushings in the upper and or lower control arms may be worn out causing your alignment to change. The harder you have to tighten the lock nuts to maintain your alignment the worse off the bushings are. Too much toe-in or toe-out on one tire relative to the other will cause the steering wheel to become misaligned. This can also happen if your caster adjuster is loose and shifts during bumps or turns. If you plan to change the ride height .5" or more it's generally a good idea to re-clock the bushings.

youngcow

Thank you for that. So what do you suggest I do? change out my bushings?

Thanks

Slowcrash_101

Inspect them, there's a little rubber tab on the bushings, if they're torn you'll see that tab no longer be alinged with the rest of the rubber. If they are bad, then yes replace them. Stay away from polyurathane bushings, as a personal suggestion, go hardened rubber, like Spoon, Mugen, or Hard Race. The upper bushings can be bought from the dealership. The dealership only sells AP2 bushings however, they'll work on the front if you have an AP1, but not in the back since the AP1 and AP2 upper control arms are different, they also use different pick up points on the subframe. So if you want to change the upper arms in the rear with an AP1 you have to go aftermarket, or find used arms with good bushings and transfer them over to your arms.

youngcow

so you don't suspect the front end tie rods?

B serious

Wait...why is tightness of bolts relative to wear of bushings? I don't believe needing to tighten bolts further than normal has anything to do with bushing wear.

Rubber bushings have a metal sleeve that the bolts clamp. The metal sleeve never wears out.

Worn bushings can cause alignment issues and bumpsteer. Have the bushings always been clocked properly?

It also may be because you have extended upper AND lower ball joints. Its the same as making your spindles longer on both ends. Your UCA/LCA angles and curves will differ a lot from stock.

hecash

Have you considered going just part way with the removal of the 12mm bump steer shims. I just bought a 25mm diameter aluminum rod and first cut it in 10mm wavers, drilled them out to make spacers, used them, and then made a set of 5mm wafers and finally settled on 8mm wafers that I felt gave me the best result.

s2000Junky

I never felt the front had bump steer tendency like the rear of the ap1. Even after lowering -2". However I added some custom 20mm thick rack spacers to put the tie rod geometry in better alignment because it makes sense and doesn't hurt anything to do so. I still dont have any bump steer issues. So I tend to not think the bump steer correction measures spoken of are the factor here. Its likely either worn bushings, failed aftermarket joints or stock rack giving out, or not bump steer at all but rather just wheel deflection, witch is something different but easily confused.

youngcow

I already removed the 12mm shims and it oddly made it better.

youngcow

The odd part is last year or 2 years ago the passenager side I had to replace 4 upper spc ball joints. It was odd they kept failing. But as of last May till now the bumpsteer is coming from driver side when I go over a bump, nothing happens if I go over an even bump, or a pothole.