Originally Posted by
reddog3
Had a tick once. Took a couple minutes to figure out it was the end my shoelace hitting the left crankarm.
That's happened to me as well. About a year ago I had an irregular sound like described and it drove me nuts for several rides. I eventually realized it was the water bottle against the bottle cage. Bending my cage a touch to add a little tension fixed it.
It could be a stiff chain link. I've had such noises and due to the length of the chain, it comes around every 2-3 pedal strokes without seeming to be in syc with anything.