Check out more MTB related videos at the My MTB Guide Youtube Channel. Below this video you find the video transcription.
The number of tools that you need for replacing your chain are quite limited and fortunately not that expensive. You’ll need a:
- Chain wear indicator, for measuring the chain wear (Park Tool CC-3.2 on Amazon.com)
- Chain device for splitting and connecting the chain (BBB Nautilus 2 BTL-05 on Amazon.com)
- Pliers if you use the connection pin method to connect the chain. This is mainly the case when you use a Shimano chain
- And optionally are specific Master Link pliers if you use a Master Link to connect or remove the chain (Park Tool MLP1.2 on Amazon.com)
DO YOU REALLY NEED A NEW CHAIN?
The easiest way to check if your chain really needs replacement is with a chain wear indicator. What I’m using here is the Park Tool CC 3.2 Chain Wear Indicator. There are two numbers on the tool indicating the amount of stretch of the chain, which are 0,5 or 0,75%.
Did you know that the stretching of your chain actually is not caused by metal extending? In reality the rollers and pins wear down, which causes some play and this adds up to the lengthening of the chain.
To check your chain for if it needs replacement, you’ll need to place the tool against the roller of the chain and try to place the other side of the tool in the chain, starting with the 0,5% side. If the chain does not fall in between the rollers of the chain, then your chain does not exceed the 0,5% stretch and does not need replacement.
If the tool does fall in between the rollers then flip over the tool and try the 0,75% side. If the tool does not fall in between the rollers, then the stretch of your chain sits between 0,5% and 0,75%. At this point most manufacturers recommend replacing the chain. It’s up to your personal preference if you replace your chain at 0,5 or wait until it’s at 0.75%. If the stress on your chain high (for example in competition) or is the price of the chain just a small fraction of a chainrings and cassette (like with high end groupsets), then I’d suggest replacing the chain at about 0,5%.
Did your chain exceed the 0.75 mark with the chain wear indicator? Then you’d might want to check the wear on your chainrings and cassette as well. Chances are that you need to replace the chainrings and cassette as well since a new chain on worn chainrings decreases performance and wears down your new chain a lot faster.
REMOVE THE OLD CHAIN
First, release the tension on the chain, this makes working on the chain a lot easier. Some Shimano derailleurs have a clutch mechanism with a switch, in this case flip it to the off position. For SRAM derailleurs with the Cage Lock option you can put in the locked position. Now shift to the smallest chainring and cog and drop the chain from the smallest chainring or alternatively remove the rear wheel.
Now check if you're using a Master Link. This is a chainlink that can be recognized by a slightly different design and sometimes different color. Technically you can remove this link without any tools. You push the two sideplates together and slide them to one another. The pin slides to the second position and you can remove the Master Link and the chain. Chainlinks can be quite stiff so a set of pliers or the specific Master Link pliers might be needed to remove them. Especially 10-speed chains and up are harder to remove due to tighter tolerances.
If you don't have a Master Link then using a chaintool is the way to go. The chain is in this case connected with a special reinforced connection pin which is usually darker in color and slightly protrudes. Removal of the chain is a pretty straight forward process. Place the chain in the chaintool and align it perpendicular with the endscrew on the tool If you have one. Make sure you are not placing the tool above the connection pin, placing it above any of the other 100 pins or so is fine. Now align the tip of the tool above the center of the pin and turn the handle. It requires some force to start to drive the pin out. Remove the chaintool and carefully remove the chain from the bike. Don't throw the chain away yet since we’re using it to measure the length of the new chain.
CONNECTION METHOD: PIN OR MASTER LINK
Before measuring the length of the chain we’ll need to decide on the connection method.
Shimano chains come with a connection pin specifically for the amount of gears the chain is for. SRAM chains however comes with a Power Link to connect the chain, this Power Link (or Master Link which it’s also called) is also specific to the amount of gears. The Master Link makes installing and removing the chain easier compared to the connection pin method. Some Master Links can also be reused several times. For Shimano you are not limited to only using the connection pin. Other brands like KMC offer also compatible master links for Shimano chains.
NEW CHAIN LENGTH
New chains are out of the box a bit too long and need to be shortened, but by how much is determined by various factors. The easiest way to determine the length of the new chain is to take your old chain and shorten the new chain to the same length. Since chains stretch over time its best to determine the length by the number of links.
Lay out the old and the new chain and align them together and mark the point where you are shortening your chain to. Just note that when you are using a connection pin, one side needs to be an inner link and the other an outer link. When using a Master Link then both sides need to be an inner links. Now drive the pin out of the chain with the chain tool, similarly to the proces of removing the chain.
If you don’t have the old chain to take the measurements from you’ll need to take the measurements on the bike itself. Measuring this way is also a good idea if you make large changes in your largest chainring or largest cog. To measure the chainlength on the bike you're going to place the chain on the largest chainring and the largest cog in the rear without letting it run through the rear derailleur. Look at the point where the chain starts to overlap. Now the most common method is to add 2 links from this point and split the chain there, but, there is a bit more to it.
If you use a connection pin, you add 2 links from the point where the chain starts to overlap. One end of the chain needs to end with an inner link while the other needs to be an outer link If you end up with 2 similar ends of the chain, 2 inner or 2 outer links, add one more link. Using the Master Link with either SRAM or Shimano you only add one link from the point where the chain starts to overlap, since the master link itself also counts as one link. Both ends of the chain need to be inner links. Add one more link if this isn’t the case.
Now specifically if you are running a SRAM single chainring system, you’ll add 4 links in total to the chain from where it starts to overlap. This means 3 links and the master link. And also here, both ends need to be inner links.
Long travel rear suspension can put more tension on the chain because of how the suspension linkage is designed and therefore a slightly longer chain may be needed. Follow one of the steps just mentioned to determine the chain length and mark that point on your chain. Now run the chain over the largest chainring, largest cog and this time through the derailleur. Bring both ends of the chain together and temporarily connect the chain so that you have length that you have determined previously. I connect the chain here temporarily with an old spoke bent into an U-shape.
Cycle through the rear suspension and there should be still a little movement left in the rear derailleur cage when the suspension is bottomed out. If you're doing this by yourself, you can deflate the rear shock or disconnect it from the linkage (done here) to get the rear shock easier in the bottomed-out position. If the chain tension is so high that the derailleur cage can’t move, add a link until little movement of the derailleur cage is possible.
INSTALL THE CHAIN
Now we’re ready to install the chain. Run the chain through the bike, through the front derailleur if you have one and paying special attention to the rear derailleur. Make sure that if your chain has markings only on one side, that this side needs to be on the outside.
Run the chain over the guide pulley and in a straight line to and around the tension pulley. Make sure that the chain doesn't rub on the notch of the derailleur cage. Now bring both ends of the chain together to connect them.
For the connection pin, slide the pin in place and position the chain tool perpendicular to the chain and pin. Now drive the pin in the chain. The main portion of the pin should protrude evenly on both sides. For 10 and 11 speed chains it should only protrude slightly on the back of the chain. Make sure the link moves freely and break off the tip of the pin with your chain tool or pliers.
To connect the chain with the Master Link you have to place half of the link in each end of the chain. Some Master Links are directional, so place them correctly viewing the chain from the outside. Bring both ends together and push on the outer plates that both sides go in to the slots. Now apply tension to the chain and the link will snap in place. You can apply the rear brake and try to turn the crank to apply a bit more force.
To finish the installation, unlock the cage or engage the clutch mechanism if you have one of these options and you’re ready to go.