Originally Posted by halfro

Are you buying it at a Local Bike Shop (LBS)? They should be able to measure your inseam. Again, inseam is not everything. If you haven't ridden many bikes it probably will not be the end of the world to get a smaller bike. when you get more experienced you'll know what feels right.

When I was a kid my parents always got me an 18inch mountain bike because I'd grow into it. I never did, haha. I ride about a 16 or 14 mountain bike. Which one felt better? To tell you the truth it didn't matter because I was having fun. If you're not racing or do super miles on the bike you can get away with anything (okay, there is a limit).

Ride you friends 56CM again. Is his stock? The 56CM Effective top tube is 22.4 inches and the 59CM is 23.1. So the reach between a stock 56CM and 59CM is less than an inch. And the difference in stand over is a little over an inch.

Smaller bike will be more agile and a bigger bike will feel more stable. I like riding smaller bikes...