Im also having this problem on my 2007 Fuji Crosstown 2.0 Hybrid. The bike was originally bought as a commuter, but I got layed off back in Oct. Since then I've joined a bike club, and am putting a lot of miles on it weekly. I'm also a Clyde. I weigh about 300 lbs. (dropping quickly though). I used to play football in high school, and also have very strong legs. This causes me have a tendency to over torque instead od spinning going up the grades. Is this really bad for the gears? I try spinning, but I just feel more comfortabe in a higher gear, and using a little more leg power when climbing. Is this a bad habit I need to try to get myself out of? Spinning in a lower gear just doesn't feel comfortable. Also, I haven't made the transition to clipless pedals, and still use platforms. I'm also getting that clanking noise when climbing, and downshifting. I usually stay in the saddle when climbing, but my legs are now strong enough again where I'm starting to stand on the pedals while starting a climb. I was on a 40 mi. ride yesterday, and a few times when I stood up on the pedals the clanking was so bad it sounded like the steel frame was going to split in two?? Does anyone think this problem might just be a RD adjustment, or have I over torqued where the cassette might be bad? I looked at the chainring, and it seems fine. No wear, and the teeth look good. I plan on taking it to my LBS for a tune-up (I get free lifetime tune-ups), but they're closed today for Presidents Day, and they're still on winter hours, and will be closed tomorrow too.