My 545i SMG started to not run well when the engine is cold.
The entire car shudders lightly, but only when I am crusing along below ~ 2000 rpms and below 40 mph.

It feels like a vibrator...

This goes away after ~ 10-15 minutes of driving.
In think it depends on the rps, but its very hard to tell.

Sounds stupid, but could it be the "cold" tires?

Anybody else have this?

Jochen

It's the cold runflat tires.. I have the same experience with my summer tires.

Mine does too, a 530i. You can feel it in the steering wheel too, especially when first starting out....

RFT tyres are a pain in the ass .......

Mine started doing that noise and vibration last week, checked with the dealer and i was told that the tyres weren't in good shape.
I'm taking the car in tomorrow for oil and filter change. They will check the tyres but i was told that it's not possible to solve the problem unless i change the tyres. The car is 23.500 kms today. One thing is for sure next tyres won't be RFT .....

My dealer told me it was the V8. It needs to properly heat up to get rid of this problem.

i have a 545 automatic and noticed the same thing on a cold morning. it goes away in less than 5 minutes...i think it's normal.

I have the same feeling too. However mine is 530i. Gonna change my wheels soon and i will update the ride.