I have a 2009 Scott Sportster P3. When I bought the bike I was really just looking for something to ride on the rails to trails with the family and on the road. I used to be a hardcore roadie, and began to get burnt out, so I sold my road bike and decided to get this bike and have fun riding again. We also have some great single track in my area and I figured with this bike I could ride some of the trails with it also. Well I've found myself having a ton of fun riding the single track now. Does anyone else use this bike for single track? Will it hold up to the abuse of mountain biking? I will not be doing any jumps or anything like that. Just single track with roots and rolling over some smaller logs and whatnot. So far it's been really dry when I've gone so I've been OK with the Continental Double Fighter II tires that came stock on it, but I would like to get something more mountain bike oriented for when it's a little muddy. I'm thinking I'm probably going to have to go with a cyclocross tire due to the lack of frame clearance. I'm just wondering if anyone else has messed around with this sort of thing yet? Other than the frame clearance issue and not being able to get a ture 29er tire on the bike what is the difference between this bike and a 29er? I'm guessing that maybe the 29er geometry is more upright? Thanks for any input. I'm absolutely loving this bike. I'm having so much fun riding again. Yeah it's way heavier than my road bike was and I go slower on the roads than my road bike, but it's is so much fun looking for the bumps on the road then trying to avoid them all the time.