Honestly, I think this is a big part of it. BUT, I'm also only 5'5", built small, and my muscles just don't have as much power and endurance to them as people who are normal sized. Yeah yeah yeah training. Well I've been riding this bike consistently for over a year, and pretty often, and I commute on a single speed, etc etc. I bike quite a bit, I think I'm just not as athletically inclined as others. Maybe a lighter bike will help. Who knows.

BUT. I don't like hills, but I can do them without a problem. In Fredericksburg this weekend, both courses were nothing but hills...BIG hills. I've never biked 3300ft in elevation gain before. And I only walked up the last 1/4 of two of them (and that was towards the end of the 60 miles). I spun up them slowly at my own pace - like 6-8mph (they were steep).

I'm only a little concerned about my ability as a cyclist - I just wish I could go a little faster. Day two started out and the riders were just blasting at like 22mph on the flats and some smaller hills, we just couldn't keep up.