ErnieN85

Third gear 100 & up full throttle causes the rear to sway from side to side one side goes up the other down then the revers about once per second. I did this with stock Z51 springs & shocks and continues to do it after changeing to LG G2 coil overs. I had one bad rear hub and changed that. possibly the other needs changed? it's been suggested it might be the clutch packs in he diff. also using Michelin PSS 345 30 19 at 27 lbs
anyone else had this problem?
and if so how did you solve it.

Racingswh

I was using the same size tires but Sport Cups and it ended up being the tires. 2010 GS. Did a ton of diag and should have just used a different tire and wheel early on in the diagnostic process to rule that out right away. That's what I would recommend knowing what I know now.

ErnieN85

Called Michelin no help there told me it wasn't a race tire and buy race tires. I thought maybe a tire engineer might help out no dice

so I tried more tire pressure went from 28 to 32 problem cured
Seems like the sidewall is too soft
now if the tread wears ok i'll stick with them

giantkeeper

I had a similar problem in my boosted C5 Z06. I changed tire brands and installed poly suspension bushings. No longer an issue.

Racingswh

It's a crazy feeling isn't it? Feels like there is no way it can be a tire and it has to be something major wrong with the car.

We must have damaged the tire or tires running lower pressures when we were first out on track because pressure change didn't make the problem go away. Only finally changing out the tires solved the problem on my wife's car.

ErnieN85

Sure is (weird feeling) I was thinking I'd need to use another brand.
The Michelin SS was really working out nice on the street. I have 20,000 on them and about 10 track days with 6/32 tread left