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).