I'm 180 - 182 and switched from a 180 f/r [Alligator Windcutters] to a 160f/140r setup [Alligator Windcutters] this season. So far in the training and three races I have been in it has been plenty of rear brake. 180 on the rear was way too much for my needs. But I live in the Midwest, so no long mountains to descend.bbgobie said:I'm 175 lbs, XC riding, some racing. At what weight do you think there is no advantage to 140mm rear rotors? Thinking of just making a switch.