Something was puzzling me over the weekend. My front wheel was going thp, thp, thp: one thp per revolution, especially noticeable when braking.
Usually this is down to a broken spoke that causes the wheel rim to go slightly out of shape. To find which spoke is broken you play the wheel like a harp, producing the sort of twink-twonk-twink-blup melody that you get a first for in Goldsmiths composition classes, whereas if you write a piano sonata you only get a 2:1. The blup is the dodgy spoke, and you take it to Bob the Wheel Builder on Walworth Road and he fixes it for a fiver while you wait and off you go.
But all the spokes were fine, twink-twonk-twink-twonk like a prize-winning etude for rubber band. It was only when I looked at the rim that I saw the problem. The wheel rim itself was worn out and had started to disintegrate. The thp-thp was caused by a rapidly-growing buckle and split at its edge, and the rims themselves had been worn concave by four years of daily braking.
Wow. Maybe time for a new wheel. Like, this morning. And maybe take the bus to work.