How To: Replace the Chain on Your Road Bike in Five Steps

If your old chain is very dirty, you can roughly clean it simply by turning the crank backwards and sliding the lower strand through a rag. After that, shift to the small chainring and the smallest sprocket so that there is as little tension on the chain as possible. If your chain is held together with a master link, find it by turning the crank backwards until it ends up in the middle of the lower run. You can also open a chain without a master link at any point. Some current derailleurs from Shimano have friction damping on the cage, which you can switch off with a small lever. SRAM equips some rear derailleurs with Cage Lock, which you can use to stretch and then lock the rear derailleur cage. Both mechanisms facilitate the following steps because they reduce the chain tension. You can easily open the master link with master link pliers. You can take apart a chain without a master link by pushing out a chain pin with a chain tool. Then, thread the chain out of the derailleur cage and remove it.

The length of the chain – i.e. the number of links – is important for your drivetrain to function properly. If the chain is too long, it will rattle and hit more and the pulleys on your rear derailleur may come too close to the cassette. If the chain is too short, you may not be able to use all the gears or the rear derailleur may be damaged by overstretching the spring. You have two possibilities to determine the correct chain length:

1. You can just carry over the length of the old chain. You could count or measure the links. However, it is easier to place the two chains next to each other or to hang them parallel on a spoke (a small hex tool also works). Due to the stretch of the old chain, the outer and inner plates will no longer hang directly next to each other at the end, but you can usually easily recognise the offset length. Mark the length of the old chain on the new one for the next step.
2. Alternatively, you can just re-determine the correct chain length. Also, pay attention to the manufacturer’s instructions for your gears. Many modern rear derailleurs work within tight tolerances and function optimally when the chain is exactly the right length. In general, we recommend placing the chain on the large sprocket and the large chainring (shift the front derailleur and rear derailleur accordingly beforehand), threading it through the rear derailleur and pulling both ends of the chain tight at the bottom so that they overlap and the rear derailleur cage is almost stretched. Mark which link of the chain you need to shorten so that it fits exactly to the other end.

Now you can shorten your new chain to the previously determined length. You do this by pushing out a pin on the corresponding link with the chain tool. You should note that a master link replaces exactly one pair of outer plates. If you want to secure the chain with a master link, you need two ends with inner plates. If, on the other hand, you want to rivet the new chain with a new pin, you need one end with inner and one with outer plates.

If you have shifted to the large sprocket and large chainring to determine the chain length, we recommend that you now shift to the small sprocket and small chainring. This way you don't have to overcome so much rear derailleur tension to secure the chain. When putting on the chain, make sure you put it on in the right direction! An arrow on one of the chain links will tell you which direction the chain must be set in. Some chains also have a top and bottom. If you are unsure how to put it on, check the manufacturer's instructions. Now you can put the chain on the small chainring and the smallest sprocket. Thread it through the front derailleur and the rear derailleur cage, making sure to stay on the right side of the small nose between the two derailleur pulleys. To make riveting or connecting with a master link easier, you can fix both ends of the chain now. For this purpose, some chain wear indicators have special hooks integrated and some chain tools come with small wire clips. Alternatively, you can also bend an old spoke to suit your needs.

To rivet your chain, you need a special chain pin. This is about twice as long as the pins of the chain. Take the two ends of the chain and place the outer tabs of one end over the inner tabs of the other end so that you can put the rivet pin through both with the pointy side first. Use the chain tool to push the pin through far enough so that it is flush with the plate like the other pins. You can break off the part that protrudes from the back of the chain with pliers. (It has a predetermined breaking point for this purpose.) Finally, check that the new connection can be moved easily. If it’s a little tight, you can carefully put some transverse strain on the link by grasping the chain with both hands and pressing on it with your thumbs. That’s usually sufficient in the vast majority of cases.

A master link consists of two equal parts. You simply insert one of them from the front into one end of your shortened chain and the other one from the back into the other end. Be sure to pay attention to the running direction of the master link! To close it, simply hook the two ends together. Make sure that both links are parallel and that the grooves of both bolts hang in the other link! Then turn the crank backwards until the connecting link is in centre of the upper chain and apply a little pressure on the pedal to put tension on the chain. You will notice that the master link audibly and noticeably engages.

Your bike is now ready for your next tour!