I have recently changed the wheels on my bmw from 15s to 18s n was wondering if it would break the diff
Tom...you're up... that's the man....but break the differential? I can't see how.
You'll just throw your speedometer all out of whack.
It will only throw the speedo out if you don't get as close to matching the diameter of the 15" set up so get an appropriate aspect ratio sized tire.
Looking for a Used 3 Series in your area?
CarGurus has 33,268 nationwide 3 Series listings starting at $1,000.
Search BMW 3 Series Questions
BMW 3 Series Experts