It clicks once a turn. Not a rattle, which is many small failures arguing. One click. Clean, dry, arriving at the same place in the circle every time, a little past the bottom of the stroke where the weight comes off the foot and the crank swings light.
I do not know what it is. I have decided not to find out, which is a decision I revisit on every ride and re-decide. It could be the pedal spindle. It could be a bearing gone flat on one side, a single ball worn to an egg. It could be the crank breathing on the axle. It is small. It has been small for two years. Small things on a bike are patient. They wait for the exact wrong hill.
For a while I did not hear it. The ear files it under road, under weather, under the ordinary noise of a thing in motion. Then one evening I heard it, and now I cannot not hear it. It is the loudest thing on a quiet street. I count with it without meaning to. Click, click, click. The bike keeping time with itself, a metronome set to whatever speed my legs allow.
There is a version of me that pulls the crank and packs the bearing and ends the click. He is a good man and I have never met him.
I flipped the bike over in the yard and spun the pedal by hand to catch it. It clicked once, alone, into the still air, and then the wheel slowed and the click came further and further apart, and I stopped it with my palm before it could arrive again.