Chainrings are a key component of your bike's drivetrain. Over time, they become worn. You'll notice wear in the opposite direction of chain travel and they will begin to look like shark fins.
It is possible for your chain to slip from one ring to another as you wear it out or you may experience "chain suck," when the chain does not release properly from the teeth on the chainrings, resulting in the chain becoming jammed.
These are all signs that the chainrings need to be replaced.
You may or may not need to remove the entire crank to remove the chainrings, depending on your setup. The article discusses how to change chainrings without removing the crank.
Video: How to Replace a Chainring
Tools and Parts for Changing Chainrings
A key component of your bike’s drivetrain, your chainrings can become worn over time. They’ll start to look like shark fins and you’ll notice wear in the opposite direction of chain travel.
With extreme wear, your chain can slip from one ring to another or you may experience “chain suck,” where the chain doesn’t release properly from the teeth on the chainrings, and the chain can get jammed.
These are all signs that it’s time to replace the chainrings.
Depending on your setup, you may or may not need to remove the entire crank to remove your chainrings. This article focuses on how to change your chainrings if you can do so without removing the crank.
Tools and Parts for Changing Chainrings
Identifying your chainring type: Depending on whether you have a traditional or compact drivetrain, as well as whether you're buying a road or mountain bike.
In some "direct mount" chainrings, there are no exterior bolts; the chainring mounts directly to the crankarm and is held in place by a lockring. There are even bikes with chainrings that are integrated with the crankarm, so you'll have to replace the whole unit.
When you replace your chainrings, what you buy will depend on how many bolts attach your chainrings to your bike, as well as a mathematical equation based on a measurement of bolt circle diameter (BCD). You should ask your bike mechanic to help you determine your BCD so you can choose the appropriate parts.
Tools:A bike's chainrings are secured to the crankset with several bolts, and different nut/bolt combinations require different tools.
Chainring nuts are bolts with a slotted channel running through the center, so you will almost always need a chainring nut wrench. Both a hex (Allen) and a torx wrench will be necessary.
Removing Bike Chainrings
First, identify the correct wrenches (chainring nut wrench, hex or torx wrench) compatible with the chainring nut on the outside of the chainring and the bolt on the back. Once your wrenches are in place, turn the nut on the front to loosen it while keeping the bolt in the back secure. Save your old chainrings' nuts and bolts to use with your new chainrings. Next, slip the chainrings onto your crankarm.
(If you are unable to perform this step, you will have to remove the entire crank, which will require additional tools and techniques not discussed in this article.)
Installing Bike Chainrings
In order to install new chainrings, you reverse the removal process, starting with the largest ring.
Slide the chainring onto the crankarm. Chainring brand names should face out (away from the bike) so that the ramped edges of the chainring face in (toward the bike). (The ramps guide your chain as you move from one chainring to the next.)
Chainrings with a large pin or tab are designed to prevent your chain from getting caught between the chainring and crankarm. Make sure the pin of the chainring is protruding away from the body of the bike and sits behind the crankarm.
Grease the bolts and nuts, then replace them with the same tools you used to remove them, but don't tighten them completely. As each bolt and nut are installed, tighten them a quarter turn, moving around the ring until all are tight. Using a torque wrench, tighten each to the manufacturer's specifications.
Make sure everything is working properly by placing your chain on a chainring and pedalling the bike with your hand. If you changed the size of your outer chainring, you may need to adjust the height of your front derailleur.
Bike Chainring Maintenance
Depending on how often you ride, you may want to thoroughly clean your chainrings at least twice a year. Find out how to clean a bike in our article, How to Clean a Bike.
If you live near a beach where sand can get into your drivetrain or if you live in an environment where rain routinely washes away your chain lube, making your chain rusty, keep an eye on the condition of your entire drivetrain.