[mlhj83]

Hello mods, given the number of complaints about steering wheel vibration, I decided to do a writeup below, and was hoping to get it as a sticky to help everyone. Happy for any feedback.

Common causes of vibration (excluding brake judder). Go through the list and eventually it WILL be solved.

1) Wheels and tyres are out of balance
2) Wheel is bent, resulting in axle or radial runout (a few millimetres can be felt)
3) Wheel hub is not sitting flush with hub of the car
4) Wheel spigot (centre bore) is not centred on the car's hub (very common with aftermarket wheels that come with spigot rings). The wheel should fit snugly around the hub lip of the car.
5) Wheel bolts not torqued in the correct pattern or to the correct value
6) Tyre has too much runout despite being in balance i.e. tyre wobbles from side to side or up and down despite alloy wheel being perfectly round
7) Tyre sidewall has variation in stiffness - cured by road force balance
8) Wheel bearing bent or worn
9) Suspension components are faulty or out of alignment
10) Brake discs/rotors are imbalanced (especially aftermarket) or have an elliptical rotation (in the radial direction) due to faulty/worn floating mechanisms or poor manufacturing.

The chassis setup of the M3 is precise enough that there is little tolerance of any imperfection. My M3 and indeed many others have been perfectly smooth from new. Any vibration is a problem somewhere. 99% of the time, it's to do with the alloy wheel and tyre. Even if the tyres and alloy wheel balance perfectly using a dynamic balancer, there are still a number of problems a wheel and tyre can have that can cause vibration namely:

A.Tyre or wheel runout
B.Is the wheel hub sitting perfectly flush with the car's hub
C.How the spigot of the wheel sits on the car's hub lip - hubcentric
D.The irregularity of the sidewall stiffness of the tyre

I can guarantee that if the wheel and tyre is properly balanced and the above 4 points are checked, 99% of vibration problems will be solved. Also note that there are broadly speaking 3 types of vibration that one can feel through the steering wheel:

Rhythmic vibration - this is due to an imbalance on the car
Road surface vibration - texture of the road surface
Impact vibration - self explanatory

Rhythmic vibration being the one that requires fixing.

Road force balancing while better than dynamic balancing still does not deal with points A, B and C. Points A, B and C can be diagnosed at home or at a good mechanic. All you need is a good eye.

My personal experience:
I had a slight vibration at the same speeds and I jacked up the car and spun both front wheels and there was a tiny bend in the inner rim of one of the front wheels - no more than 2-3mm out of trueness. Had it fixed and all was good. Had another set of wheels custom powder coated and ended up vibrating, which turned out to be due to the spigot having a bit too much paint and not allowing itself to sit perfectly flush with the hub of the car.