Originally Posted by 1QuikWS6
You'll be fine - that's what I have run on my 328iX E92 for years with no problems. XDrive between E90/E92 is same - one not more sensitive then the other...
Tire sizes = 25.09" Dia Fronts/25.03" Dia Rears
For the longest time those were the reccomended tire sizes for use with 8-8.5 Front wheels/9-9.5 Rear Wheels according to TireRack & many others.
In recent history people have been pushing it and using larger sizes - in the end, it's the OD of the tire/wheel combo between Front/Rear that need to be <1% difference
i'll be doing the same set up 225/40/18 front and 255/35/18 rear but will have 15mm spacers for the rear only. Will the spacers have any effect?