Dirt Bike Chain Adjustment

dirt bike chain adjustment

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The bike bottom bracket basic

Crucial to the crankset is the bottom bracket. Of all the bearings on a bike, the bottom bracket is the one that has to bear the heaviest load. Not only does the bottom bracket have to spin while you pedal, but it takes the force of all the twisting and turning that occurs during pedaling.

There are two main types of bottom brackets:

Adjustable: If you have an older or lower-end bike, you may have an adjustable bottom bracket. This type of bottom bracket has a cup that holds bearings and an axle that spins within the bottom bracket. An adjustable bottom bracket is much more susceptible to wear and tear than a cartridge-type, because water and dirt can enter the cup where the bearings are held. Plus, an adjustable bottom bracket needs to be adjusted perfectly, or the bearings will prematurely wear out. If you have this style of bottom bracket you may want to think of upgrading to a cartridge bottom bracket. At the very least, you'll want to overhaul the bottom bracket at least once a year — more often if you do a lot of biking in wet or muddy conditions.

Cartridge: Most newer bikes have a sealed-cartridge style of bottom bracket. A cartridge has a longer life than an ordinary bottom bracket — because they're sealed, water and dirt are kept away from the bearings. They're also easier to install and maintain because they don't need to be adjusted the way standard bottom brackets with cups and cones do. The other advantage to cartridges is that installing them is easier and quicker. When they do finally wear out, you replace the entire cartridge. But don't worry — you'll ride several thousand miles before you need to go shopping for a new bottom-bracket cartridge.

If the bottom bracket is squeaking or if the cranks don't rotate smoothly by hand with the chain off, it's time to overhaul. If you hear any squeaking or grinding, if the bottom bracket is slightly loose, or if you feel a vibration when you pull on the cranks, you should also prepare for an overhaul.

Adjustable bottom brackets should be overhauled as part of your annual maintenance. Cartridge bottom brackets are replaced rather than overhauled — and replacement isn't usually necessary until you've ridden a few thousand miles.

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