Thanks for all the replies. I was talking with a bike repair guy, and he mentioned how it was odd that I had mountain bike wheels on my hybrid. My bike has a pretty high top tube, and if you just replaced the handlebars and tires, it would look pretty much like a road bike. Is it possible that the 26" wheels are mismatched to it? The front and rear wheels seem to be of a different make. The bike is at least 3rd hand, and it's fairly old (mid 90's, I'd say). The fit with respect to the fork & brakes seems good, though. If it isn't the original wheel, which road bike wheel size would you guess it came with?