I'm 6'4 @ 240 lbs and ride a Trek hybrid. I've owned the bike for a year and some change. I've been very happy with the bike, but the rear rim is killing me. The factory rim (Mavic 550 perhaps?) would occasionally pop a spoke (at the rim). After 5 I decided to talk to the LBS about an upgrade. The showed me two rims. The better of 2 was the one I purchased (Sun CR18 700c). 2 weeks later I pop a spoke @ the hub. They replace it. Tonight, same thing. I'm losing patience/getting frustrated. I'm very careful how/where I ride. Is the rim not up to par? If it makes a difference, I ride 28mm tires @ 110 #'s of pressure.