rsbob 

If you are over 50, it is more than likely one of your knees.

Broctoon

I recently had something similar. Started out as an occasional click or "tick." It progressively got more frequent and louder, and happened especially when I'm pushing hard on a climb. It developed almost into a creaking or groaning.

I started pulling things apart to inspect and try isolating it. One of my bottom bracket bearings was getting rough. I'm 90% sure this is the culprit.

I'm going to order new bearings. Haven't decided whether to buy the tool to pull off the old ones, borrow it from someone, or just take the crank to a shop and pay them for the work. In the meantime, I was able to pry the seal out of the way enough to pack in some new grease, and that seems to have worked as a temporary solution.

Eric F 

Clearly, the answer is that you need a new bike.

Broctoon

I like how you think. Unfortunately, that attitude is how I got a garage full of bikes, enough that I can ride a different one every day of the week. Since I don’t want to get divorced, I’ll probably just replace the bearing.

Eric F 

Get divorced. She takes half. You get to buy more bikes to refill the stable. I fail to see the problem.

Follow me for more relationship advice.

mikeymichaels

Sources of noise to eliminate include: handlebar/stem, headset, axles/skewers, rear wheel/spokes, pedals, cleats, shoes, rear derailleur hanger, chain, and finally bottom bracket.

I had a single click per crank rotation that I'd narrowed down to the bottom bracket. I ignored it for about a year, until it became louder and evolved into several clicks through one crank rotation. I could no longer stand it because I could hear it bouncing off walls, curbs, etc. A new bottom bracket seemed to take care of it, so far.

bleui

just to add recommendation on things to check, I just found the culprit of the ticking noise on my bike was a bad cartridge bearing (9000km+) on the inside part of the freehub

rsbob 

If you have Look Keo pedals, you have found the issue. Thought my bottom bracket bearings were absolute toast on one climb, then I replaced them with my old Deltas and the bottom bracket was miraculously healed. Praise the Deltas!

Gonzo Bob

WHen one of my bikes starts making a clicking noise while pedaling, it is almost always one ot the chain ring bolts. Snug them up and see if that fixes it.