Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I got a folding bike 2 months ago and got my first hiccup. It has a 3-speed hub gear and while changing gears today, it seems like the chain slipped off the smaller chainring near the back wheel into the gap with the wheel. As the chain is quite tight, my basic knowledge or Youtube info on how put chains back on in dérailleur bikes is useless.

How do you actually slide it back on? Is there a simple technique? I tried simply pedalling but it doesn't seem to make a difference.

If this matters, it's an S-RAM iMotion hub gear.

share|improve this question
You may not have had enough chain tension. Solution is probably to loosen hub nuts, slide wheel forward to get the chain back on the sprocket, and re-tighten hub nuts with appropriate chain tension. – Jason Brown Mar 20 '14 at 17:38
You should first put the chain on the rear sprocket, then pedal it on to the front one. This way it's easier. – Alexander Mar 20 '14 at 23:10
The chain is actually quite tight now, I can barely move it and I don't see immediately how to take it off the front sprocket. Any possibility to do this without tools? Thanks for your input by the way. – Kurt Mar 21 '14 at 15:11
Get it of the front sprocket by pulling it to the right while turning the sprocket forwarth. It should come of. Now put the chain on the back sprocket. Get the chain on the front sprocket again by pushing it back on a very small part of the sprocket and turning the sprocket so that it will 'pick up' the chain. If your chain came of, it will might have been to lose as Jason Brown said. – Foxhill Mar 26 '14 at 16:17

I also have a folding bike with a 3-speed hub (Shimano Nexus 3). My bike has a chain protection cover in the front chainring, so I find it harder to follow those other suggestions. I usually prefer to put the chain over the front sprocket in the first place.

The chain is also as tight as I can, but sometimes it happens that it falls over. I have noticed this happens when pedaling on a more irregular road or over bumps, so I just stop pedaling for a moment or go slower.

This trick is pretty easy and fast:

  • Grab the chain and put it over the rear sprocket (assuming it is already over the top of the front sprocket).
  • Because the chain is tight, probably, it will only be possible to move it over one or two teeth -- no problem.
  • Let the bike go backwards a little bit. The rear sprocket will spin together with the wheel and it will pull the chain over the sprocket.
share|improve this answer
Might be that your chain is too loose or too tight. Also watch out if you've pedalled and got the chain wedged down beside the spokes.... I've managed to munch off some spoke heads doing this. – Criggie Nov 9 '15 at 20:58
Thank you for your comment. When I touch the chain it looks properly stretched, anyway, it is really hard to make it even more tight, but it should be possible. I don't have that problem with the spokes, this hub has around 2 cm of clearance between the sprocket and the spokes. – iled Nov 10 '15 at 12:08

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.