Okay, maybe I'm not REAL fast, but I go forever. I'm a distance runner and just started biking, and really like it, but I find I get some pains in my shoulders in my lower back after long rides. I figure it's mainly just not being used to it, and overdoing it too soon - going on 3-4 hour rides with no experience. Got the wind, just not the muscles in the right places. Raised the seat some, it was too low to start, might raise the stem, too. Flat handlebars, a little higher than the seat. I'll give myself some time to adjust.