I am building a fixed gear road bike and am buying wheels that'll handle my size (319lbs measured yesterday) and am looking for recommendations on a tire. I've run 26x1.25's (559-32) at 100psi and those were fine. I am thinking about going smaller though. Would a 28mm tire at 120psi be ok? I have somewhat rough roads around here, and as my fair weather commuter it'll get beat pretty good Performancebike.com owes me some tires, so I am thinking about getting their cheapest kevlar 700c tire, but I can't decide which size!