Singlespeed & Fixed Gear - Converted bike, chain falls off

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.



PDA

View Full Version : Converted bike, chain falls off

Mayday.JP
06-19-12, 11:18 PM
I'm posting this to inquire for my brother. I've personally never have had much experience with single speed bikes and my brother recently got an old peugot 9 speed bike and he took the gears off to make a single speed. He got the fixed wheel rear tire but the geared crankset stayed. The chain stays on fine but after a few mins or riding, it comes off everytime. We've tried tightening the chain, loosening it up but it falls off everytime. He's getting frustrated because he's had it for a few months and can't seem to fix it. Would the solution be to get a single speed crankset or is there something else we can try?

Also, he has the single speed chain he bought as well.

Thanks

Nagrom_
06-19-12, 11:23 PM
Sounds like the front chainring is worn, and the chainline is probably off.
Street rider
06-19-12, 11:38 PM
My first thought was chainline. Maybe try putting it on a different cog of the cassette?

linus
06-20-12, 06:22 AM
Chainline it is.....
nuhtowel
06-20-12, 07:08 AM
you might be able to get away with getting a bottom bracket that has a spindle length of around 110
Bat56
06-20-12, 08:31 AM
If fixing the cabin line doesn't work, look at the chainring and make sure it not bent.

I don't think it's the frame, but it could be some serious flexing taking place. Are you guys sumo wrestlers?
m4rx12
06-29-12, 09:23 AM
Look up a chart which explains how many spacers you need to align chain. Also pics would help.
Scrodzilla
06-29-12, 09:36 AM
If fixing the cabin line doesn't work, look at the chainring and make sure it not bent.

Definitely the cabin line. I had a crooked cabin line once and it was a real ***** to deal with!
prooftheory
06-29-12, 09:49 AM
Cupertino (http://en.wikipedia.org/wiki/Cupertino_effect) from cbain.
chas58
06-29-12, 09:59 AM
what cog is he using? A good FG cog is designed so the chain stays on the cog. If you used a cog from a multi-speed cassette, it is designed for you to easily shift gears (not good if you only have one gear).
CaptainCool
06-29-12, 11:29 AM
If fixing the cabin line doesn't work, look at the chainring and make sure it not bent.
Check the spindle too -- see if the chainring wobbles left to right at all when you spin the crank. My old bike had a slightly bent spindle, and the chain went from overtight to a bit too slack in each turn of the crank.