i would suggest, like others, that you go with a steel ride, as they're more forgiving and comfortable. whetever bike you decide upon i would say you must make sure not to get fancy low-spoke-count wheels (not that any of the bikes at this price point come with them stock, but in case you come across something used that does). ideally you would want 36 spoke wheels, but as these guys tend to come with 32s that'll most likely be what you get, and they'll hold up ok. but i wouldn't go for anything with less, at your weight.