[CronicArt]

That's hard to say. It depends on the kind of riding he does. I do alot of single track riding so I wanted a good bottom end for powering out of turns. Usually never seeing anything higher than 2nd gear. I also wanted a little more use of third for the more wide open areas and moto tracks. I went for a 2 tooth larger rear which makes third much more useable. For me a front spocket change would have been a bit more than I was looking for. When in doubt just get him the same size he has and keep the receipt.