I try to race, even at 250 lbs. The mountain courses in CO have some pretty good climbs, several at over 9,000'. I switched to running the 30 and 42 rings, from a road triple, and an 11-26 cassette. The 30x26 allows for some serious steeps, even for a fat guy like me. Anything you can't ride in that gear should definitely be run (walked in my case). In fact, I havent found any hill that I didnt have enough gearing for this year - the ones I have run were due to trail conditions, not gears.