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      02-24-2013, 12:32 PM   #14
ortho281's Avatar

Drives: 2011 E92 M3 6MT
Join Date: Aug 2010
Location: Katy, TX

iTrader: (1)

Originally Posted by Tobbep View Post
Finally had my M3 serviced at BMW. They re-balanced the wheels and performed a new alignment to dial everything in.

I took the M3 on the freeway to see the results. The strong vibrations, I'm glad to report, are gone...

I assume there was a combination of issues that caused the bad vibration (wheel balance, alignment, and uneven suspension height).

In regards to the height of the suspension. The M3 was sitting uneven when I initially had the rear suspension dialed in using the collar height. I talked to KW and they told me to adjust the height using the "Wheel Hub to Fender edge" measurement as a guide. When I initially had the suspension dialed in equal on both sides (using the collar measurement) the height was off left vs right. KW told me that some M3s sit different than others so you can't rely blindly on adjusting the suspension height (using the collars as a guide) but instead measure the height from the wheel to the fender.

We adjusted the height until we had an equal distance on both sides. Ground to fender measurement at the rear was 26" at the end.
I choose to corner-balance to adjust ride-height instead. My rear ground to fender measurement was 25.75" (front 25.6") at max lowering with corner-balancing. Both front and rear have settled another 0.25" since then.
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Akra GT4 / MS Stage 2 / MS UDP / BPM Tune / KW CS / H&R Sways / TMS Delrin / ST 380/355 BBK / Cantrell 2.5" Ducts / SR34 Pads / Apex Arc-8 / Hoosier R7's / Mode GT4 Splitter / GT4 Canards / APR GT-250 Wing / Cantrell Half Cage / Recaro Pro Racer / Schroth Profi II-6 / BMW Alcantera Wheel / Cool Shirt / ESS Fire Supp / Solo DL