[Teddyc]

Hoping anyone can shed some light on a strange issue I have with my winter set up and brakes:

I put 18 inch Brembo wheels with Winter tires 245-40- 18 ( non run flats) on my 2020 m340 xi, at pick up I noticed on the first push of the brake pedal the pedal would go almost to the floor. On the second press the pedal firms up and only goes down about 2 inches (Normal) .

Prior to the winter tires I was running 19 inch non run flats PS4 's

I took it to the dealer who initially said that there was nothing wrong with it, but after a test drive with the shop foreman; he agreed that the pedal was very soft on the first push and had too much travel.

Bled the brakes, no change...

Contacted BMW in Germany and they recommended swapping the 19 inch wheels and tires back on (which I thought was stupid) but in any event it somehow fixed the brake pedal problem.

I have had the brake recall done (Software patch ) prior to the swap.

Can anyone explain to me why the heck different wheels and tires would change the brake pedal feel/ travel?

I assume its a software issue and not a hardware issue... but it is weird.

The winter tires are not the exact right width and diameter for the car, (came off my old Audi s4) but that should not really matter for the brake pedal feel and travel.

To be clear this is not an ABS issue, or traction control, just the actual brake pedal travel and feel.

And now I still need a winter set up...

Any thoughts appreciated...

Ted

[themnmd]

That's odd, don't see how tires size or type would affect break feel. I would buy ride quality steering or handling