At least these things don't happen very often...
The same weekend the boiler in our house broke down, I was nipping out to the shops for some bread when I heard a crunch beneath me - and the bicycle stopped moving forward. I was in the middle of a roundabout when it happened; not the best place to be. But if you are riding a bicycle when something mechanical goes wrong, it is likely that it will go wrong while you are somewhere hazardous. Thankfully no one was driving fast around me, and I was able to walk out of the road.
Trying to reconstruct the incident, I think the chain somehow jammed in the rear derailleur and dragged it round with the cassette. It twisted and snapped away from the rear mech hanger and jammed in between the spokes and the mudguard supports.
Beside the road I was able to dismantle the rear derailleur and remove it from the frame. The chain had twisted and so this was easy to separate it to remove. I rolled home to inspect the damage more comfortably. Despite giving the bike a clean after every winter ride; the road grime does build up in hard to reach places. Eurgh.
One of the jockey wheels had sheared in two, the bolt-hole on the derailleur had also snapped in half. The cage is utterly twisted.
This rear derailleur has passed on. It is no more. Has ceased to be. This rear derailleur's expired and gone to meet its maker. Its a stiff. Bereft of life, it rests in peace... Its kicked the bucket, shuffled off this mortal coil, run down the curtain and joined the bleedin' choir invisible! This is an ex-rear derailleur.
Less humourously though, the twisting/snapping action has also bent the rear mech hanger. Now this is more of a problem because the rear mech hanger is part of the frame and the frame is titanium. I'm a bit worried about this. I've already been in touch with Spa Cycles
and I'm taking the frame down to them this week to see if the rear mech hanger can be straightened.
Although we are still in the middle of winter, and although the gritters are out tonight spreading salt on the road; I'm going to have to use the new chain and cassette I was saving for the spring servicing.
The metal supports for the mudguard were slightly bent, but easy enough to bend back and no problem there.
The only remaining annoyance is that some of the spokes on the drive side of the rear wheel were pinched and will need to be replaced. The wheel isn't very old, so I'm hoping that it is a simple matter of replacing the damaged ones - please don't let it be a new wheel.
I could do without an expense like this, but being car-free means that I have to get it done. However, on the bright side, when a mechanical problem hits a bicycle it is a lot less expensive than an equivalent problem with a car.