6'1 with different setups, 175 and 172.5. Over 60,000 miles, 35 or so centuries and I stil can't tell a difference in crank length.

1 mm = .039...so 2.5 X .039 = .097 of an inch which is less that 1/10 of an inch. If that affects your pedal stroke, you are very sensitive. That's less of a difference than inserting and insole which many riders do.

It would make a differnce in lenght if it were a dude 6'7 and 180 cranks vs a 5'2 with 172.5. Then you are talking a difference, but other than that.....Pfft!

I've read one statement that said a 172.5 corners better than a 175. Sure, if you're dumb enough to take a sharp turn and lay the bike down on it's side with the pedal down!