[rak299]

The G20 (and F20) have the same diameter wheels front and rear. The G80 M3 has the rear wheels an inch larger than the fronts. Why?

[AlterZgo]

Because the M3 is a high performance, high horsepower RWD car that needs significantly wider rear tires to provide more traction. Therefore, it comes with 10" wide rear rims to fit the stock 275-35-19 or 285-30-20 width rear tires.

[rak299]

I understand wider. I asked about rim diameter

[guess2098]

Because all super cars do that.... BMW just copy it jk, base on what I read, taller sidewall in front helps turn and smaller sidewall in rear help for traction. That is the general idea. F8x CS GTS all have 19 20 wheels