How to Replace or Fix a Chain on a Bike
The components of your bike will ultimately wear out if you ride it often. A bike chain will “stretch” after a certain number of miles and need replacement.
Technically, the chain isn’t extending; rather, the pins holding the links together are deteriorating, lengthening the chain. It’s a good idea to change your chain when you detect a substantial stretch, or every 750 to 1,000 miles, since a stretched chain accelerates wear on your bike’s cassette and chainrings. A chain may be replaced for a lot less money than a cassette or chainrings.
The following information may also be used to shorten or fix an existing bike chain.
Chain wear tool: A typical chain wear tool has one end that enters into the gap between two rollers while the other end hooks over one roller (or pin) in your chain. The tool’s numbers will show how worn your chain is and if it needs to be replaced.
Chains have a particular speed range. Therefore, if you have a bike with nine speeds, get a nine speeds replacement chain. Higher-end chains have rust-delaying coatings or are constructed of stainless steel rather than normal steel.
Replacement Pin or Master Link: To join the two ends of the chain together, new chains will either come with a new pin or a specialized link known as a master link. Replacement pins or master links may be purchased separately if you’re fixing an existing chain; they should work with the speed and brand of your chain.
Chain tool: If your chain has standard links, you will need a chain tool that is compatible with your chain so that you may quickly break and rejoin your chain by removing the old pin and inserting the new one.
Master link pliers: If your chain has a master link linking it to the rest of the chain, you’ll enjoy these pliers since they make removing and rejoining the master link much easier.
How to Examine a Bicycle Chain
Use a chain wear tool to inspect your chain for excessive stretching. One end should be positioned over a chain roller (or pin). The other end may either sit on top of the chain or be inserted into the gap between the two rollers. If it lands in the space between the rollers, your chain is stretched and has to be changed.
Tools for measuring chain wear feature stamped-in numerals that show how worn your chain is. If the reading is between 0.5 and 0.75, your chain has to be replaced. Whether the value is 0.75 or higher, you should replace your chain as well as inspect the state of your cassette and chainrings to determine if the stretched chain has worn these components down excessively.
Measuring the chain with a ruler or tape measure is another approach to look for chain strain. A brand-new chain will have precisely 12 complete links that are 12 inches long (measured from pin to pin). You must replace the chain if the length of the 12 links is 12 1/8 inches or more.
Removal of a Bike Chain
You must detach the chain, also known as break the chain, in order to remove the chain from the bicycle. Depending on whether your chain contains a master link or not, there are a few different ways to do this.
Change your chain to the smallest chainring and cog before you start. Better still, pull the back wheel off the bike or unchain the front chainring. Both techniques will release the chain’s tension.
If your chain is a standard design without a master link, seat it in the chain tool with the pin facing the pin in your chain. Turn the chain tool’s handle until you can break the chain by pushing the pin out sufficiently enough.
You can tell whether your chain contains a master link by checking for a link that looks quite different from the side. You will break the chain at this point.
The master link has a notch on one side and a pin that fits into it. To pop the link open, press the master link pins toward one another using master link pliers.
How to Measure the New Bike Chain Length
A new chain will often be too long for your drivetrain right out of the box, so you’ll need to reduce it by removing links. There are a few ways to do this.
Laying your new chain out next to your old chain is the best and simplest method to measure its length. then cut your new chain shorter to match the previous one (double check by counting the links).
The chain may also be draped over the large chainring in front and the large gear in rear by passing it through the front derailleur. The chain should not yet be fed through your rear derailleur. The chain’s two ends should be brought together and pulled tightly. The point where the chain joins plus two complete chain links (or one inch) of overlap is the proper length for the chain (you will have an additional half link at the end where you will connect the chain).
(Note: A common feature of full-suspension mountain bikes is “chain growth,” which involves moving the rear axle further from the bottom bracket as the bike travels through its suspension. When employing the aforementioned technique, you will need to completely compress the rear suspension to account for this chain development.)
Make sure the two remaining ends of the chain can connect to one another before eliminating the additional links: Only by joining the inner plate of the connecting link to the outer plate of one link can a chain be linked. Use a chain tool to eliminate the superfluous links.
How to Install a Bike Chain
Chain must be properly threaded through the pulley wheels.
It’s time to reattach the chain by passing it through the rear derailleur. Keep a careful eye on how the chain is routed through the pulley wheels of the rear derailleur.
Using a chain pin: If your chain is missing a master link, use a chain tool and the chain pin that came with your replacement chain to reattach the chain.
Always use a new chain pin rather than recycling an old one when mending an existing chain. Your brand and chain speed should be compatible with your new pin.
With the majority of brand-new chain pins, you enter them halfway with a chain tool before using pliers to cut off the end that is sticking out.
Using a master link: To use a master link to rejoin your chain, lay half of the link onto either end of the chain, bring the ends together, assemble the link, and then use a master link tool to snap the link into place.
reattaching a master link to a chain
Without a tool, a master link may be linked. To achieve this, put the link together and do your best to lock in the master link by pulling the sides of the chain apart. When the master link is on top of your drivetrain, remove the derailleur clutch if you have one, spin your pedals so that your brakes are engaged, and stomp on one pedal forcefully to tighten the chain and click the link into place.
Keep a closer watch on the state of your chain if you live near a beach where sand might enter your drivetrain or in a damp area where rain often washes away your chain lubricant, causing your chain to rust. Both have the potential to hasten the chain’s wear. For further advice, see our article on basic bike maintenance.