Originally Posted by Minimization
By the way, all the 0-60 mi/hr times in 4.1 s in this car have been clocked with these optional 19", so any theoretical inertial disadvantages of the slightly higher mass or larger diameter do not translate to the real world.
Have you seen tests where the 18's are slower as accomplished by the same tester? Doubtful, unless you test the same car on the same day with 18s and 19s that statement can't be proven.
However, BMW itself states that the 18s are faster on a road course track. I'm sure the marketing dept doesn't appreciate BMW employees saying that though.