Any "Car Talk" fans here? This one is for you!
For two years now I've been trying to track down the cause of an intermittent "click" that I hear on each rotation of the cranks when under significant load, which I can only reproduce while riding. I don't have to pedal very hard, but I can't do it with my hand on the stand. This is a 2000 Lemond Zurich, double chainring, original Ultegra components but chain replaced a couple of years ago. Probably around 10,000 miles on the bike.
Each time my right foot starts to rise (or left foot starts to descend) while pedaling with some effort, I hear a "click." Here is what I have done to try to track it down:
Shift between chainrings: No effect. Clicks on either chainring.
Shift among rear cogs: No effect. Clicks on any gear.
Inspect front derailer: Doesn't appear to be rubbing.
Stand off of seat: No effect; doesn't appear to be seat post.
Let go of handlebars; No effect; doesn't appear to be stem or bars.
Loosen and re-tighten all chainring bolts: No effect. Everything seems tight.
Replace pedals with spares: No effect. Not the pedals.
Bottom bracket regular maintenance overhaul at bike shop: No effect.
Believe it or not, I seem to hear this problem more on hot days than cool days....
Any ideas are appreciated.