What options do I have if my rear derailleur breaks when I'm out on a trail? I ran into an unfortunate situation earlier this week. I was out on a mountain bike trail, alone — just me and my hardtail. I'm pedaling, when I suddenly hear a CRUNCH and my bike stops. The hanger has broken, and the derailleur is totally bent.



I couldn't pedal, because the derailleur would travel with the chain and get stuck in the gears, and I had no way of reattaching it.

Luckily, I happened to be pretty close to the town when this happened, so I ended up walking it for ~15 minutes and dropping it off at my local bike shop.

However, I'm wondering what I can do if this happens again and I'm at a less convenient location - say deep in the woods. I don't generally carry any tools besides for a Swiss Army knife and an Allen wrench set.

Is there anything I can do to patch it up enough to at least get back home if I happen to break my derailleur?
If you carry a multi-tool which happens to include a chain tool, you could also convert your bike to a single speed. If you do so, you would have to replace the chain afterwards as well (since you shorten it) but in some situations it could get you out of a rural area.

If you do so, carefully select the gear you would put it in, as you won't be able to shift anymore afterwards.

There is a nice video online illustrating the idea: how to do a roadside fix of a broken rear derailleur.
GCN has some more videos online explaining roadside repairs of various issues, which may also interest you. 

Additionally, I always take a missing link with me, as it allows you to get home after a broken chain. This speed link can also be used while converting your bike to a single speed.