Often, the link you’ve just joined is stiff, although stiff links occur for other reasons: the chain may need lubricating, or you’re riding in the wet. You feel a stiff link as you’re riding – the pedals slip forward regularly, but at different places in the pedal revolution.
To find a stiff link, change into the smallest sprocket at the back and the largest chainring at the front. Lean the bike up against a wall, crouch beside it and pedal backwards slowly with your right hand. The chain heads backwards from the top of the front chainring, around the smallest sprocket, then around the front of the guide jockey and the back of the tension jockey. Then, it heads to the front chainring again. The chain is straight as it travels across the top, then bends around the sprocket. The links should be flexible enough to straighten out as they emerge from the bottom of the sprocket, then bend the other way to pass round the guide jockey. But a stiff link won’t straighten out as it drops off the bottom of the cassette and then passes clumsily around the derailleur. Once you’ve spotted the area of the chain that’s causing problems, slow your pedalling right down and check each link as it comes off the tension jockey.
Step 1 : Once you’ve identified the problem link, get your chain tool out. You need to use the set of supports nearest the handle – the spreading supports. Look carefully at the problem rivet to identify whether one side of the rivet sticks further out one side of the chain than the other. If it is uneven, start with the sticking-out side. If it looks even, start with either side.
Step 2 : Lay the chain over the supports nearest the handle of the tool, and turn the handle clockwise until the pin of the chain tool almost touches the rivet on the chain. Wiggle the chain to precisely line up the pin with the rivet. Turn until you can feel the pin touching the rivet, then just a third of a turn more. Back off the tool and wiggle it to see if the link is still stiff. If it is not yet as flexible as those around it, repeat from the
other side of the chain. The rivet needs to end up as even as possible.
Step 3 : If you don’t have the chain tool with you, hold the chain as shown and flex it firmly backwards and forwards between your hands. Stop and check frequently to see if you’ve removed the stiff link. The last thing you want is to go too far and twist the chain plates.
A split link, also called Powerlink, is a quick and easy way to split and rejoin chains. It is particularly useful if you like to remove your chain to clean it, since repeatedly removing and replacing the rivets in chains can cause weak spots. It’s also a great emergency fix. You still need your chain tool for removing the remains of twisted or broken links, but the split link will not be stiff when you refit it and does not shorten the chain.
There are a couple of different types of split links; the best is the Powerlink, which comes free with SRAM chains. All split links work in similar ways. The link comes in identical halves, each half with one rivet and one key-shaped hole. To fit, you pass a rivet through each end of the chain, linking the ends together through the wide part of the hole. When you put pressure on the chain, it pulls apart slightly and locks into place. They never release accidentally.
To split the chain, locate the split link and push the adjacent links towards each other. The Powerlink halves are pushed together, lining up the heads of the rivets with the exit holes. You can then push the two halves across each other to release them.
Powerlink – the quick and easy way to split and rejoin chains
Source : BIKE MAINTENANCE TIPS, TRICKS & TECHNIQUES