Chain falling off during folding
Old ID
Symptoms
I have a new Bike Friday Metro. When folding, the chain often slips off the chainring.
Causes
The chain can have a tendancy to slip of during the folding process. This is due to the chainline angle induced as the rear triangle swings on the folding hinge and the reduced tension on the rear derailleur.
Solutions
See more general tips for keeping the chain on here.
On our newer bikes that fold to the left, we recommend putting the chain on the smallest chain ring in the front AND the smallest chainring in the back. This is to minimize the angle that the chain is twisted when the bike is folded, and to minimize the amount of torque that might get applied to your front derailer, assuming you have one.
For older right fold bikes: Before folding, shift the rear derailleur to put the chain on the second or third largest cog. This puts the chain under more tension which helps keep it on the front chainring.
If your bike has a single front chainring, installing a chain retainer (sold by Bike Friday) can be a very effective solution. On bikes with front derailers the chain retainer is not as effective, and can possibly add unwanted chain tension that could bend your front derailer. Even without the chain retainer, it is important to mind the chain and crank position when folding pocket bikes with front derailers to prevent damage to the front derailer. (This does not apply to Air Bikes) It is possible to keep the chain on in some casese, but it's best to accept the fact that the chain does want to fall off and simply pull the chain off so that it rests on the inside of the chain ring.
Written May 23, 2001 by Bike Friday staff member Garner Britt .
Updated Jan 2008 by Lynette Chiang
Updated Nov 2008 by Tim Link