Good morning and happy holidays!
There's a ticking or clicking sound when pedaling my 2010 Cannondale Synapse 5 with about 10,000 miles on it. I'm pretty certain it's somewhere in the chainring, bottom bracket, pedal area. Here's why I think that: There is no clicking when coasting. There is no clicking when lightly pedaling or when spinning even under power, only when mashing. When mashing or out-of-saddle accelerating (like up a hill or when pulling away from a stoplight), a clicking sound is heard at the top (or bottom on the other side) of the pedal stroke.
Because it doesn't happen when coasting, I don't think it's in the rear wheel/hub or cassette. That also rules out the speed sensor on the spoke.
What it isn't: Because it happens prominently when I'm out of the saddle, I don't believe it is the saddle squeaking. It also isn't the front derailleur cable hitting the crank arm; the cable is bent way back out of the way. The clicking is still there when the chain is dead center in the front derailleur so it isn't that.
What I have done: I installed a brand new MegaExo 6600 bottom bracket, properly torqued to the correct nanometers and the sound is still there. I removed, cleaned, greased with high quality bike grease, and reinstalled the pedals and the left crank arm. The clicking is still there. I even removed the pedals and added a little plumbers pipe tape but the sound is still there. I've also checked, greased, and retorqued the chainring bolts but that didn't get rid of the sound, either. I'm out of ideas.
What's left that it could be? Could the threaded sleeve that the bottom bracket screws into actually be the culprit? Could there be a micro crack in the bottom of the frame? Could the chainset itself be the problem and it needs to be replaced? At this point, I would be willing to change the entire chainset and pedal assembly if it would fix it but that won't help if the problem is in the frame. Your thoughts and wisdom would be appreciated.