I have a new 04 Ironhorse Sport with about 25 miles on it and I have noticed a little "clunk" on the down-stroke with the left pedal. It's pretty quiet and I believe I can feel it more than I hear it. I notice it less when I'm standing or sitting and really pedaling hard. I'm starting to think that this is the free-wheel in the hub disengaging for a moment due to a pause in my pedal stroke. In other words, for a moment the rear wheel is moving faster than the pedals and what I am hearing and feeling is the hub re-engaging when the pedals catch up with the hub. My reason for thinking this is that the feeling and the noise seems to disappear if I keep constant pressure on both pedals all the way through the stroke. Is this normal? I don't want to pull the BB out, etc, for a wild goose chase...