Change a Chain on a Mountain Bike

No matter how cheap or expensive your bicycle is, there will come a day when you need to fix or replace its chain. The structure of a mountain bike may be more complex than the structure of a regular bike, but the chain changing process is similar. With the right tools and a little bit of patience, you'll have a new chain on your bike in no time.

Steps

Removing the Chain

1. Secure your bike. It's unlikely that your kickstand will be sufficient for you to get a good look at your bike without it falling over. A bike rack that has hooks from which you can hang your bike works very well, but you can also turn your bike upside down so it rests on the seat and handlebars.
   • Inspecting your chain with your bike's wheels facing upwards will make it more comfortable for you to inspect and work on.
   • You can make a simple bike rack with scrap parts. All you'll need are hooks and a frame. Insert hooks into 2 x 4 boards oriented vertically and attach those boards to a sturdy base, separating each board by the distance between the hubs of the wheels.
2. Check for a master link. A master link is a special link in your bike chain that has a pin/slot configuration that will allow you to easily remove your chain from the bike. Two popular kinds of master link are Connex and SRAM Powerlink. Knowing where your master link is ahead of time will make chain replacement go smoother.
   • If your bike does not have a master link, you can install one yourself or have it done at your local bike shop. This installation is usually inexpensive, costing about $15 in most cases.
   • If your bike does not have a master link and you prefer not to have one installed, you can use a special tool called a chain-tool to remove the chain.
3. Position your chain. This is especially important if you have a master link. Removing a master link that's positioned on the teeth of the chain ring or a gear can be very difficult. Positioning the master link so it is suspended at the midpoint between wheels will be easiest.
   • If you are using a chain tool, you can still benefit from proper chain positioning. Some parts of your chain will be dirtier or have more wear than others. A clear segment of chain positioned at the midpoint between the wheels will be easiest to remove with your chain tool.
4. Clean the chain. Bike chains are greased to improve their performance and prevent the elements from causing the chain the degrade quickly. It's likely that a layer of gunk has accumulated on your chain. Clean this with a rag that's been dampened with degreaser and wipe free the buildup and grease.
   • To gain access to the full length of chain, move the pedals with your hands to rotate it through the drivetrain until an uncleaned section of chain is available.
   • If you lack chain degreaser, isopropyl alcohol (rubbing alcohol) or paint thinner both work well as a substitute.
5. Remove the chain. Now that the chain is in position, you can remove it. With a master link, you can do this by squeezing both ends of the master link inwards with your hands or a pair of small pliers so the pin comes out of its slot and the link comes apart, freeing your chain. If using a chain tool, you should:
   • Set the chain tool on the link you are trying to remove so it aligns with one of the round holes to either side of the link.
   • Screw the chain tool so it moves through the hole. This will push out the pin that is keeping that link together. Try not to push the pin completely free of the link. This will make it difficult, or in some cases impossible, to reassemble that link of the chain.
   • You'll often feel a popping or snapping when the pin pushes free of the link. This is a good indicator that the link has been disengaged.
   • Some chain tools are only intended for certain sized links, though some can be used on several different sizes of chain. Check the instructions on your chain tool before using it.

Attaching Your New Chain

1. Avoid using failed chains as replacements. Chains generally fail because they have reached their limit or been put under too much stress. Replacing a failed chain on your bike could result in an even more severe failure down the road. To prevent injury to yourself or your mountain bike, you should buy a new chain instead of reusing old ones.
   • Bike chains can be bought at your local bike shop or, in some cases, your local hardware store.
2. Measure your replacement chain. It's important that you only use the kind of chain intended for your bike. For example, an 11-speed bike will use an 11-speed chain. Hang your old bike chain so it dangles freely and do the same with your new chain beside the old one.
   • Count the number of links your new chain is longer than the old. This will be the number of links you need to remove.
   • If your chain has snapped and it is unreliable to measure your new chain, you can remove links after feeding the chain into the drivetrain of your bike.
3. Insert your chain into the gear mechanism. For more complex mountain bike, you may need to consult the picture you took of how the old chain feeds through the gear mechanism to do this properly. Simple mechanisms may be more intuitive. Pull the chain through the entire drivetrain until both ends terminate at either the top or bottom midpoint between your wheels.
   • Positioning the ends of your chain at the midpoint between the wheels of your bike will make it more accessible, which will make the reattachment easier.
4. Attach the loose ends of your chain. With a master link, all you need to do is slip the pin of the link into its slot to complete the link. If you removed your chain with a chain tool, you'll have to re-couple the split link by lining up its halves together and using a pair of pliers to force the pin back through the hole to complete the link.
   • You should feel a click or a pop when the pin of a master link slides into place. You can also pull on the chain to either side of the link to securely seat the pin of the master link in place.
   • If you were not able to measure and shorten your chain beforehand, you should notice that your chain hangs somewhat loosely in your drivetrain. For the best ride, you'll need the chain to be strung tautly between the wheels in its lowest gear.
5. Remove extra links from the chain, if necessary. If your chain is loose, you'll need to remove some links. This is likely the case if you were not able to measure your chain. Shift your bike to its lowest gear, and then use your chain tool to remove links one at a time to shorten the chain until it is taut in the drivetrain.
   • When removing extra links, avoid popping the pin holding them together completely free of the link. This will make it difficult to reattach the link if you shorten it too much.
6. Prevent chain binding for full suspension bikes. As your suspension compresses, the chain of your bike will adjust. This can cause chain binding and make your bike difficult to ride. Take your bike off its rack and then:
   • Vent the compression element from your shock or disengage it. This can usually done with the press of a button on the shocks of your bike.
   • Bike shocks are generally be located on the front frame of your bike around where the frame of your bike forks to the wheel.
   • Press down on the seat of your bike firmly until the suspension is fully engaged. When your bike can compress no further, your suspension is fully engaged.
   • If your chain remains taut, your bike is good to go. If, however, you notice the chain loosens, you'll likely have to remove another link or two. If it resists the compression of your bike's suspension, you may need to add a link.
7. Test your chain. Reposition your bike back on its rack and move the pedals manually with your hands to run the chain through the drivetrain of your bicycle. The chain should move smoothly. If you notice stiff links, these are often caused by a protruding link pin, and can be fixed by resetting the pin with your chain tool and pliers.
   • To protect your chain from the elements and to help it run smoothly in your drive train, you should lubricate your chain with a suitable bicycle chain lubricant.

Inspecting Your Chain for Wear

1. Evaluate the wear on your chain. The most reliable way of doing this is with a chain wear indicator, which you should be able to purchase at your local bike shop or maybe even at a hardware store. You'll have to attach the indicator between the links of your chain and follow the directions on it to interpret its reading.
   • Most chain wear indicators will have a sticker that establishes the values for a worn chain and an unworn chain. If your wear indicator does not, check the box it came in for these values.
   • If you do not have a wear indicator, you can perform a hand check of the chain. Use moderate pressure to lift a section of your chain from the chainring of your bike with your fingers. A small gap should form between the chain and the ring. If you can clearly see through the gap over three or four teeth, your chain is worn.
2. Try to join the ends of your chain to test wear, alternatively. If inspecting your chain with a wear indicator or a physical gap check aren't an option, or if your chain is already off the bike, you can also check for wear by trying to touch the ends of the bike chain. Lay your chain on a clean surface so that the holes in the chain are oriented up and down. Then:
   • Try to touch the ends of the chain together while keeping the holes facing up and down. Over time, chains are bent by the action of your bikes derailleur.
   • Note the amount of sideways flex in your chain. A worn chain will have a great deal flexion. Newer chains resist touching and only arc slightly.
3. Familiarize yourself with the drivetrain. The drivetrain of your bike is the part that transfer the energy you put into the pedals through the chain to your gears to move the wheels. You'll want to pay extra close attention to how the chain feeds into the gears. Knowing how the chain fits in the mechanism will allow you to replace it with greater ease.
   • You might want to snap a few pictures of the gear mechanism(s) on your bike with your phone before removing the chain. You can consult these pictures later on, if you're having difficulty reattaching the chain.

Things You'll Need

• Bicycle chain-tool (for bikes without a master link)
• Chain degreaser (or isopropyl alcohol)
• Chain wear indicator (optional; recommended)
• Rag
• Replacement bike chain

Related Articles

• How to Change a Bike Chain on a Mountain Bike
• Lube a Bicycle Chain
• Adjust a Rear Bicycle Derailleur
• Shorten a Bike Chain
• Maintain a Mountain Bike
• Fix a Slipped Bike Chain
• Grease Bicycle Wheel Bearings

Sources and Citations

See also

• Lubricate a Bike
• Fix Brakes on a Bike
• Shorten a Bike Chain
• Change a Bicycle Brake Cable
• Fix Stuck Bicycle Brakes
• Fix a Broken Bicycle Chain
• Put On a Bicycle Chain
• Lube a Bicycle Chain
• Adjust a Front Bicycle Derailleur
• Change a Rear Cassette

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