Emergency single speed conversion

[Cassie]

OK, So I saw quite a few broken chains & deraileurs on my last MTB race...

 

This made me think (afterall, I had many km's of the race left to do and my mind wandered...)

 

Can one simply shorten the chain into a confortacle gear and splice with a chainlink? OR is it ~25 odd km of walking freewheeling back to your car???

 

[ViperSquad]

Yes. Done it Myself when I bent my derailleur going through freshly cut grass.

[NotSoBigBen]

Yip, LittleBen done it at SabieX last year! Just select a gear front and back that keeps the chain as straight as possible else it can jump around .....

[Johan Bornman]

If your jockey goes AWOL, what else is a man to do?

 

[Hog_]

The trick is to keep the chain as straight as possible. I made the mistake of having it skew so the chain forced itself onto a bigger gear, locking up the drivetrain completely.

 

 

 

[100Tours]

A few tips:

 

1. This is much easier to get right if you're riding a hardtail. If you're on a softtail, the distance between crankset and cluster will vary as you go over bumps and your singlespeed solution may tighten up, or detach itself as you go. Lock out the rear shock to mitigate against this (it will still happen, but you'll feel better about it).

 

2. Keep trying different ratios until you get one that fits just right - in my experience most combinations do not work - The chain will be too tight to fit on to your first choice of gear (and your second and third choices too), or if you make it only 1 link longer it will have much too much slack. You will only have 2 or 3 feasible gear choices out of the 27 possible combinations on a 3x9 drivetrain.

 

3. Once you have found an appropriate combination, make note of where you are going to cut the chain, and break and reassemble the chain "loose" (i.e. not wound onto your chosen gears yet). When the chain is whole then wind it onto your chosen ratio by hooking one or two links onto the gear and turning the pedals to bring the rest of the chain on (This only works with gears that are designed to be shifted - true single-speed gears do not have the required "pickups" to help the chain climb on in the first place).

 

4. This is an emergency repair only - generally you have to get the chain quite tight to prevent it slipping off, and this may result in damage to the drive side BB bearings (again, more so if you are riding a softtail). Pay attention to any tightening up in your cranks after having ridden your bike using this singlespeed arrangement.

 

Having said that I have used this solution successfully to get me home over 50km riding a GT iDrive. This was a whole lot better than walking, and buying new BB bearings didn't break the bank either.