A friend has a 2004 Cannondale r600 caad5 with a Truvativ ISIS BB and double crankset for a 2x9 speed drivetrain. He would like to change to a compact double and I happen to have a spare Shimano Hollowtech compact crankset for 2x10. Are there any issues with making this switch? Also, he is about 6'2" and it is a 58 cm frame with 175mm crank arms. My cranks are 172.5. 2.5mm just seems like too little to worry about.