How To Change A Bicycle Chain

Hello, my name's John from On Your Bike, in London. I've been a bike mechanic for twelve years. I'm going to show you a few things about bikes, things like saddle height and setting it up so that it's the correct size and a few maintenance tips as well.

How to change a bike chain? You probably even might need to change it if it's been on the bike a long time or it's worn or it's stretched. There's a few ways you can check to see if it's stretched. Take it to your bike shop or if you've got a chain checker, you put that into the chain and then if you move that, it will tell you how worn it is.

On this particular one, it's in good condition, it's only about 25% worn. Another way of checking is when the chain is on the large ring, just to make sure it sits on there perfectly. If you see daylight or if you see it pulling away, down on the bottom, it means that it's stretched.

Or if you push on the pedals, when you're riding say, up a hill and it slips, then that's another indication that your chain is worn and it needs replacing. If your chain is worn and it needs replacing, then you'll have to take the chain off of the bike. You'll need one of these, which is a chain tool, and what this does is push the pins in and out of the chain, to take the chain on and off.

I'll show you how to do it. That goes in there like that and all you do is wind the tool in and then that pushes the pin through. As you can see, the pin has now come out of the chain.

I gently just twist and that will release the chain. And that's the chain. How to fit the chain, onto the bike, after you've cleaned it, or if you have to fit a new one, all you do is start feeding it from the back, it's got to go around these wheels, these are called jockey wheels.

Go through there. This is the front derailleur, which changes the chain between the rings at the front. You make sure that you fit it through there as well.

Then to reconnect the pins, you twist it, you should be able to get it back in position. On some chains they have a connector, like a quick connector, and then that just snaps together, that saves having to knock the pins out. Just push that pin back in.

So, that's reconnected. .