[SaNGRia]

Hello guys. Thank you mlhj83 for the details. Really helps alot. I would like to share my situation before i attempt to replace some parts. I might get some help here to determine the problem.

I have sunday drive 08 e93 m3 with KW Sleeve overs for about 5 years now. But i owned the vehicle since 2012. And the intermittent vibration is really annoying me. When the car was stock height with stock wheels it was solid and never had any issue. Then i got custom made 20 inch wheels with F : 265/30/20 and 285/30/20 setup. Wheels made for the car they re hub centric 72.6 exact. I also added BBK 380s all around so had to use 4mm custom made spacer in the rear with hub extender. But never had any issue. Vibration was there before or after. I dont think there is nothing to do with that spacer. Fronts never had spacers and they are torqued correctly.

2 years ago i had this wobbling feeling on high way and decided to replace the control / thurst arms using oem product. While i was doing it i also got new Hankook tires v12 k120s. And i am running this tires since i have my custom wheels. SO with the brandnew control arms + brandnew wheels + really good alignment i was still getting this vibration randomly. The weird part is one day is rock solid , one day shimmy. i cant really understand the logic. Thats why i am writing here.

After having the issue with brandnew setup, i took the vehicle to a brandnew tire shop here which they were just opened and had brandnew laser balance machine. They only do tire replacements and balance nothing else. so they found out the front driver or passenger side was little bit out of balance so they rotated the tire around the wheel to make perfect balance. And all my balances done Road Force so i was having little hope that would solve the problem but did not.

After that rotation process, i have a little air leak on passenger side which i will address it soon, so i try to keep each wheel at the same psi before start driving. And i know that uneven tire pressure also causes shimmy steering. But all being in the same psi also doesnt help.

My next step is replacing the front Wheel hubs and front struts but before i do that what is the impact of the tire brand?

If i replace them to Michelin PSS, them being better sidewalls might solve the issue? Or getting a monoball control arm bushing can decrease the shimmy steering wheel feelings on a lowered e9x m3?

After having this issue, i have talked my 3 buddy. They all have this shimmy feeling at 60-80 and one of them has brandnew bbs with brandnew tires w KW v2 kit. SO lowering the m3 definitely causing some issue on steering feel i think.

(As a note here, when i was stock i did push the gas little hard while i was turning on intersection and the car slide little further than i expected and the front driver side wheel touch the side wall slightly and made a curb rash. but it was really minor. This always make me think of what if the driver side wheel hub somehow effected.) . I put the new rims quickly after this situation. and slightly sanding my old rim really remove the curb rash before i ship them out to the new owner.

I hope i explained my situation enough to find some solutions here. Thank you.