Originally Posted by Feanor
I'm a bit puzzled about the offsets being different though - I thought they had to be the same?
Or do the offsets differ depending on the wheels that the car comes with? To be honest though I don't really understand what the offset measurement really means.
Regarding the mounting specs, it sounds like you're saying that the info on the website is wrong?
As for the tyres being taller, do you mean the profile is bigger? IE the /xxR figure? (eg /45R or /50R)
The offset of a wheel is the distance between the centerline of the wheel and the plane of the hub-mounting surface of the wheel, and is measured in millimeters.
The F30 has bigger wheel bolts, 14x1.25 (14mm thread diameter) vs 12x1.50 (12mm thread diameter) on the e90. But I'm pretty sure M14 bolts fits through the holes on e90 wheels.
Yes, the profile is bigger, e.g 225/45/18 on f30 vs 225/40/18 on e90, so the profile is "5 more" on the f30 on same width tyres.