Hello,
I had a very pleasant outing on Saturday with a friend of mine in the Cevennes. Unfortunately my friend managed to snap his rear derailleur hanger. The whole rear derailleur went into his back wheel and he stopped rather abruptly. Weirdly this happened on a dead straight downhill tarmac road after he hit a small pothole. I can only think that it was already cracked and the bump finished it off, as his chain was in the middle of the cassette and he wasn't changing gear or even turning.
We broke the chain, removed the mangled derailleur and looped the chain back on as a rather slack singlespeed. Fortunately the final 15km was either downhill or flat, so we got back to the car, but every so often the chain would move up to a bigger cog and jam solid - it was tight enough to go on, but too tight to turn!
This has got me thinking. I've now seen 4 people snap their hangers, and have to walk back. I don't want this to happen to me.
The simple idea would be to carry a spare hanger. But having seen how manged the rear derailleur was, and how twisted some of the chain links were, I doubt if we could have got it all back into place. I also doubt that we could have removed the broken hanger pieces without a workbench and some proper tools.
So... I'm thinking of making, and carrying with me a DIY singlespeed tensioner. All I need is a piece of flat metal, drilled for a QR axle at one end, with an old jockey wheel at the other and bent to go under the chainstay. This should give just enough tension to prevent the chain wandering all over the cassette (I can even ziptie it to the chainstay if it keep loosening too much). Googling shows a fair few of these (although I might not use a spoon).
Has anyone tried this ? Is it a daft and unnecessary idea ? Is making and carrying one of these things a waste of time and effort ?