To fix a fallen bike chain, loosen the chain on the rear derailleur cage and pull down to gain slack. Fix a slipped bicycle chain with tips from a bike mechanic in this free video on bicycles.
Hi this is Jeff of the two wheeler dealer. Today I'm going to show you how to fix a slipping bike chain. If your chain is slipping this could mean one of two or three different things. Could mean that your drive train is worn out, if it's slipping especially under high load, if you are riding up a hill or really cranking out of the saddle, and you notice that it's just straight slipping off on you, it's very high probability that your chain has worn out your rear cassette. Which is the cogs in the back here. Once that happens the teeth wear narrower and it allows the chain under high load to slip right over the tops of them. If this is the case you need to bring it into your local shop and have a professional diagnose this and determine any replacement parts that may be needed. If the chain is just falling off, especially on the front chain rings here, this can be pretty easily solved by de tensioning the chain on the rear derailer cage and pull it down just like this, it will give you the slack underneath it, from there you can just reach up, start at the top of the inner chain ring and just lay it back down across and it should, should just tighten back up and lay on there. If none of these two things solve your problems I highly recommend bringing it in and having a professional take a, take a second look at it. And that's how to fix a slipping bike chain.