This article is a step-by-step procedure on replacing a mountain bike cassette & chain.

Featured parts used here are:

SRAM 8spd (11-32) cassette

SRAM 8spd Powerlink chain (top chain is old, bottom chain is new & longer)

Tools required for this job are:

Cassette lockring tool (SRAM cassettes are compatible with Shimano lockring tools)

Chain-whip tool

Adjustible Wrench (for use with Park Cassette lockring tool)

Torque Wrench (ft-lb/Newton Meters)

Chain Tool

First, either place the bike on a stand, or upside-down. Shift the rear derailleur to the highest gear (smallest cog). Remove the rear wheel from the bike. Remove the old chain utilizing a chain tool. After removing the old chain, use it to make sure the new chain has the correct number of links. If not, remove the extra links from the new chain.

Remove the quick-release skewer/axle from the rear wheel. Insert the cassette lockring tool into the splined lockring.

Now use the chain-whip tool to keep the cassette from spinning as the lockring is being loosened.

Once the lockring is removed, the first two cogs will come off separately. The cassette should then slide smoothly off the hub. If it doesnt, apply some quality degreaser into the spline area between the cassette & hub. Let it set for a while, and then try again. If it still refuses to come off; flip the wheel over and using a small hammer and 6″ wooden dowel, tap the cassette off the hub body.

Be sure to take this opportunity to clean the hub body. Apply a quality anti-seize compound to the hub splines.
Locate the indexing spline on the hub body, and then match it to the index slot on the new cassette. Usually this index spline is smaller/narrower than the others. Line up the splines and slide the new cassette onto the hub. Make sure the cassette is seated fully onto the hub body.

Then, place the two small cogs onto the hub, making sure they are seated properly against the new cassette. Finally, install the new cassette lockring, but do not tighten yet.

Take note of the torque markings on the lockring! Then use a torque wrench to tighten the lockring onto the cassette.

Spin the cassette by hand to ensure that it moves freely and does not wobble. Fit the new chain around the derailleur guide pullys and the smallest front chainring. Again using the chain tool, fasten the chain back together (if using a standard chain, SRAM Powerlink chains do not need a chain tool).
Reinstall the rear wheel back onto the bike, and the job is done!

To replace a mountain bike chain, you’ll need a chain-tool. Some chain-tools have removable bits that are different sizes for different link-pins. Most mountain bike chains have the same link-pin size, so do not be concerned if your tool only has one bit. The Park Chain-tool is a good choice, as it has a large handle and two chain-placement channels.

First, clean any excess dirt or grease off your chain. Do this by holding a rag lightly moistened with chain-degreaser around the chain, beneath the bottom-bracket. Work the chain through your degreaser rag by backpedaling, and make sure you grip the rag lightly.

After you’ve degreased & cleaned the chain, it is now easy to see the pins on your chain. Work around the chain, looking for the “Connector Pin” that some chains have. This pin will appear different than the rest, and will not have “peening” around the head. On some chains (Shimano), the pins are peened, which flares the head of the pin, adding extra strength to the chain. With Shimano chains, a pin which is pressed out will sheer off the peening, which weakens the chain. These pins with sheered-off peening must be replaced with “connector pins”.

Connector pins are long, with a tapered end & a peened end. After inserting the connector pin fully into the chain link, the tapered end is broken off.

When selecting a pin to press out, do not select either a connector pin, or the pin next to it on the same link!

On other chains (SRAM), look for a “Master” or “Quick Link”. This is a section of chain that is slotted, allowing you to separate the chain by sliding the links together. Reassembly is the reverse.

Place the chain inside the channel on your chain tool, making sure it’s fully seated inside the cradle.

Then turn the press handle clockwise, until the removal bit contacts the pin. Make sure the bit is on the center of the pin; then continue, pressing the pin fully through the link and out the other side.

Now that the chain is separated, and replacing the chain is the reverse, except for a few steps. Make sure that the chain is routed correctly through the rear derailleur pulleys, and through the front derailleur as well.
If the chain had peened pins, the “connector” pins are used at this point to rejoin the chain. Slide the connector pin into the chain, tapered end first. After the peened end is even with the other pins on the adjacent links, break off the tapered side with a pair of pliers.

On a “master” linked chain, grasp the two ends of the chain and hook them back together with the sliding links.

Run the chain through several cycles, looking for stiff links. If one is located, observe the link pins for uneven protrusion. If it is the pin which was just replaced, use the chain tool to evenly seat the pin so that it is the same as it’s neighbors. Chain link failure is often the result of protruding pins or bent plates.