So I'm riding into work this morning.  Braking as I come down to a bend on the shared-use path (never actually seen a pedestrian there, but hey).  Sudden scraping noise from the rear wheel followed by a thunk-thunk-thunk noise.  Immediately stop.  Spin the wheel with my hand and get the same thunking.  Check the brake blocks (V-brakes) and the off-side (not drive-side) brake block is off-line so I adjust it and spin the wheel again: same noise.

I ran my finger around the rim and found a 'spike'.  Right on the wear line there's a little spike of metal, almost a small cone about 3-4mm diameter and about 1-2mm high.

The tyre is still inflated, but the spike was catching on the rear brakes.  So, I disconnected the rear brakes and walked the rest of the way into work.

So my question is: is this an ex-rim.  Has it shuffled off this mortal coil?  Or can I grind it flat again or something?

(Would appreciate any adice on here, before I go into my LBS and look stupid).


DaSy [742 posts] 4 months ago
1 like

Sounds very odd!

Have you got a photo of it, to get some idea of what it is?



brooksby [2235 posts] 4 months ago

No - I probably should have done that.  Anyway, I had a word with my LBS and went down there at lunchtime, and they tell me that the rim is a bit worn but nowhere near dead.  The mysterious metal lump is (they think) a piece of metal which has been picked up and then they said "welded" (though I suspect not literally) onto the rim by the brakes.  Weird: never heard of it before but he said they do get it from time to time.  The mechanic chipped it off with a chisel, and then sanded it smooth: good as new (well, good as it was... ).