Any ideas, the chain kept coming off my langster, so I gave it a good service. New BB, chain, sprocket etc and I still have the same problem, when riding over anything bumpy the chain hopes off at the back, it feels almost as though the chain is seizing and hoping off.
I had been running the bike with the wrong size BB which I thought was the problem. The new BB is the correct size for the frame/crank so the chain line is now as it was when it came out the factory and it all looks to line up.
Chain is tight but not too tight.
Anything else I should look at?
chains either not tight enough or your wheels slipping forwards.
hhmm, it might just be that simple. How tight is tight enough?
As above, how do you keep your wheels in tension?
I use Surly TuggNuts on mine and have no issues
half inch movement up and down is a good start
also check that the tensions constant through the full rotation of your rings , if your chainrings bolted to the spider off center a perfectly tensioned chain can become untensioned part way through
also everything is singlesped right - sprocket/chain and chainring ?
i found the chain has to be exceedingly slack to come off propper SS kit on the road bike :s
i just tighten mine up with a ring spanner good and tight - no slippage issues ever.
also check that the tensions constant through the full rotation of your rings , if your chainrings bolted to the spider off center a perfectly tensioned chain can become untensioned part way through
This is a good point. Too many people check the tension at one point but it does vary throughout the pedal stroke.
Yes, check tension at several points on a rotation. Are you using SS chain?
I use a tugnut equivalent on the drive side, to stop the axle slipping forward
did you get all the chain and sprocket pitches to match? i.e. all on 1/8ths or all on 3/32
You can use a 1/8 th chain with 3/32 sprockets but not the other way around. you can check chain tension by spinning the pedals and then holding the bike sideways so the chainset is on the top but horizontal to the ground if the chain is too loose it'll drop off
The Sheldon method is to loosen the chainring bolts and set the chain tension to be even before retightening. Since chainrings are seldom centred perfectly. I run mine at 1/4 inch slack at most. As mentioned, if no tugnuts, use a ring spanner to get it tight. I also found larger sprockets and chainrings helped keep the rear wheel in place.
Finally, check the chainline is straight, although if it's still running the original setup , I can't imagine it's this
Thanks everyone, tightened the chain and its all good. Have noticed tightspots, so the Sheldon method sounds good.