Hi guys,
So an unfortunate turn of events required me to change a rear wheel mag.

I can now use a set of 18in wheels and buy new winter tires, or I can use the set of brand new 17in Pirelli winter tires that have been sitting in my garage with my 17in wheels in the rear.

I would have this setup:
Rear: 17in - 255 / 40 /R17 - 8.5in
Front 18in - 225 / 40 /R18 - 8in

Using a tire size calculator, I get a circonference difference (delta) of 0.4% which is in the norm (1%) for a 335i xDrive.
My question is this: beside aesthetics, can I run with a 17in rear / 18 in front wheel setup without any issues if the circonference difference is < 0.5% ?

Thanks!