[bgconley]

Hi all -

Coming here to say that I'm experiencing the exact same thing on my brand new (less than 400 miles) 2025 X5 xdrive40i. Has been happening since the moment I left the lot. It's only noticeable in comfort mode - in sport mode the downshifts are quick and smooth without any vibration.

In comfort mode, I find the vibrations to be most noticeable in the seat of my pants when braking between 35 and 15 mph, though often strongest between 18 and 25 mph. When the car downshifts, the lumpy juddery vibration can be felt in the seat. I find it to be extremely annoying.

I also believe it's coming from the mild hybrid system. What is frustrating is that the demo X5 I drove before purchasing mine did not exhibit this behavior at all - so I know it's possible to have one of these vehicles that is silky smooth across the whole range regardless of driving mode.

I was reading somewhere that the MHEV generator has its own set of belt tensioners and the generator itself has its own internal weights for balancing the motor. I wonder of some of our vehicles have improper tensioner settings or the internal weighting is off, which would lead to this behavior. That said, we'd be hard pressed to get the dealer to check the tensioner on these systems as I'm sure even they barely know how this stuff works and likely don't want to muck around with it.

Frustrating on an 80k vehicle, especially when there are copies floating around there without the problem. I might schedule a visit with the dealer and ask them to check MHEV generator tensioner to see if any adjustments can be made which could lead to an improvement of this condition.

Edit: I should note that I've tried the neutral trick and the car brakes silky smooth with no vibration at all as expected.

Hopefully we can collectively find a solution to this.