That's not completely true, depends on tire brand. I have Falken rears and there is no stretch on them and my rear wheels are 20X10.5

 

Can I use 255/30/20 in front?

 

No, unless its not M5

 

Member xBMWx has that size tyre in front. Again, it depends very much of offsets and other things.

 

I am looking at the 20" BBS CH-R's with a 24mm offset, am I better off with the 245/30/20 in front or 245/35/20? Its for my 07 550i

 

Again, it depends the wheel width and the offset. If the offset is low (aggressive), the tire may rub the edge of the wheel well on the outer side. If the offset is high, the tire may rub the shock.

What's the wheel width?
Of course you would be better with the bigger tire to get some protection.

- Antti -

 

The wheels are 20X9 front, offset is 24mm
rear is 20X10.5, 24mm offset

 

Thanks Antti

 

I think you'd be fine with the 275/30 R20 rear, but the front wheel offset/width makes me think if the tire would rub the strut...? Even if the tire was the smaller 245/30 R20.
Of course it would be recommended to use the same overall diameter tires in front and rear though. So if you can find out the suitability of the front wheel for your ride, I would recommend the bigger 245/35 R20.

Please note I have never had 20" wheels (until this summer), so my opinions base on research and the help of other members.

- Antti -

 

Thanks for all the input, I really need to research this more, maybe members that are running this setup can chime in! I have always wanted to run the BBS CH-R Black