[Banana Clipper]

As the title says, the car shakes at all speeds while braking if any kinds, whether light, normal, or emergency. Car also shakes slightly when accelerating quickly. Starts speed does not make a difference.

Acceleration shaking could be unrelated and is very different from the shaking felt during braking.

Took it to the dealer today and they said they need the car for about a week to figure out the issue. The problem with that is the car is lightly modified and they said any warranty work would be voided due to the mods (that's a different argument). Initial feedback from the SA is that there are worn bushings but wouldn't speculate further than that

Car has been on KWv2 for about 2.5yrs/9k miles
Has 10mm Dinan spacers (I'm thinking this is the culprit but assume I'd feel shaking at cruising speeds and I don't)
Rear tires are new, fronts only have 12k miles on them

Again, the car does NOT shake all the time. Only under specific conditions
- braking from any speed with any pressure level applied
- WOT acceleration, starting speed does not matter

Just looking for input and possible causes and to see if anyone has experienced this.

Already speaking with my local Indy shop to diagnose.

I feel like it's a cop out for the dealer to blame the car being lowered as the cause but what can I do.

[Bc2005]

In most cases the dealer mechanic has limited understanding of exactly how all the suspension components work together. He/she has a book with measurements and calibration procedures, and is only trained to follow that procedure and make the proper adjustments. Once you lower the car or make other suspension mods, the “book” measurements from BMW are no longer applicable.

He/she cannot diagnose or fix it because of the non-standard parts. It’s the same principle used when a computer is really screwed up - reload an OEM copy and start over.

[Banana Clipper]

Originally Posted by Bc2005

In most cases the dealer mechanic has limited understanding of exactly how all the suspension components work together. He/she has a book with measurements and calibration procedures, and is only trained to follow that procedure and make the proper adjustments. Once you lower the car or make other suspension mods, the “book” measurements from BMW are no longer applicable.

He/she cannot diagnose or fix it because of the non-standard parts. It’s the same principle used when a computer is really screwed up - reload an OEM copy and start over.

You could be on to something here...thinking back they just gave me the thicknesses of the rotors and pads which says nothing about if they're warped.

Hopefully the Indy will get me sorted. Thanks

[Elderado82]

Did you ever figure this out? Also, when you mention the shaking, is it throughout the entire car, or is it felt primarily through the pedals, steering wheel, or both?

[Banana Clipper]

Shaking was felt throughout the entire car.

As I suspected BMW Dealership was blowing smoke and the rotors were out of spec. Replaced both front rotors/pads and the issue was immediately gone