[davem3fan]

Remember, tire sidewall is part of the tuning of the suspension!

I accepted a long time ago that BMW M Engineers likely do most things for a specific reason... So I figured that if I was going to screw around with the tire sizes, the mild 10mm increase front and rear keeps things in proportion.

I also recall that a former BMW NA M Brand Manager told us at the M3 Launch that all their E9X M3s on 18" wheels (in the hands of test drivers) were always faster than those they tested with the blingy 220M 19" wheels. The 19" wheels were a fashion demand, not a function demand.

However, the 19" 359M "Comp" Wheels have an "easter egg" with the extra 1/2" of width that makes the 255/275 setup pretty much ideal.

It puts a bit of "square" sidewall compliance back into the assembly.