How to Service Your Mountain Bike Cranks

Several components work together while you ride a bike. Cranks are part of your bike’s drivetrain, which helps drive the chainring. Bottom bracket axles are connected to pedals via two cranks and are usually mounted 180° apart.

Sometimes they get squeaky, and that’s why they need some services or replacements. Try to remove the pedal and the old cranks first with some necessary tools like an Allen key or hex keys. Then install the new cranks and put the pedal and other parts as usual.

In this write-up, we’ll help you with the full procedure of removing and installing your mountain bike cranks.

Things You’ll Need

  • Soft ended mallet
  • Allen keys
  • Workshop grease
  • Crank extractor tool

How To Check If There’s Any Problem In Bike Cranks

First, inspect the crank arms, including the chainrings, if they are in good condition. Figure out if you find any cracks, dents, or damage seen. Any movement in the crankarm will suggest that you must adjust the bearings.

When there are any bends in your pedal or crankarm, take the pedal off and try to give it a spin. However, if there is no damage, and it spins smoothly, then surely your crankarm’s bent, so you have to replace it.

If you experience any of these issues in your mountain bike crankset, you need to know that your bike is in awful condition. Now you need to fix them, and here we’re to give you some principle information for your cranks service.

How to Service Your Mountain Bike Cranks

What do you do when your crank is squeaky? It’s a signal that your bike cranks need a service. Here are some easy tips on how to change your mountain bike cranks-

Identify Crank System

Normally, crank systems have become more complex in recent years. You must know what kind of crank and bottom bracket bearing system is installed in your bike.

Remove The Pedals

Cranks are the parts of your mountain bike that transmit power from the pedal to the chainring. A rod connects the crank and pedal; you need to fit your wrench here while removing the pedal.


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    The rod should now come out of the crank arm when you turn your wrench counterclockwise. Continue rotating your wrench until the pedal is removed.

    It’ll take 10 to 30 full rotations while doing this. With the pedals loosening, the crank’s bolt will freely rotate.

    Similarly, you can adjust the left pedal. As the left pedal is reverse-threaded, you can use a 15 mm wrench to loosen it.

    On the right or drive-side of your bike, slowly turn the crank arm clockwise. For non-drive side crank arms, rotate them counterclockwise.

    After removing the pedals, aside them in a safe place, as you need to reattach them after installing the cranks.

    Remove The Cranks

    Some cranks have metal and plastic caps; now remove the cap first. With a screwdriver, pry out the caps from their fitting. With this, you can reveal the crank bolt. Crank bolts have hexagonal shapes and are centered on the crankshaft.

    The top of some crank arms has pinch bolts or smaller bolts. Then rotate the Allen key counterclockwise through the holes of the bolts.

    When you lose the bolts, it’ll help you to remove the crank arm. Don’t get worried if your cranks don’t have any pinch bolts, skip the step.

    Unscrew the crank bolt with an Allen key. Just turn the handle counterclockwise for this. If both sides of your bike have the same bolts, remove the other side.

    Check your bike manual and what type of Allen key it requires, as most of them need 4 mm to 8 mm. You’ll find these Allen or hex keys at any local hardware shop.

    Now pull the crank arm away to remove it. Remove the bottom bracket’s other side and slide the crank’s remaining part out of the bottom bracket by pulling it away.

    Use your crank extractor tool from a local shop and insert it into the crank-bolt hole. Until it tightens, screw it in clockwise.

    You should turn in the extractor handle counterclockwise now. Check the opposite side crank too and remove it with a similar procedure.

    Install The New Cranks

    Choose the right cranks that match the type, model, as well as length. It depends on the bike you use, your height, and the Q factor. All these will help you to determine when choosing cranks for your bike.

    After selecting the right crank:

    1. Push the crankset on the right spindle.
    2. Try to wrap the chain around the chainring.
    3. Twitch the crank arm and then push the spindle down.
    4. Replace the crank bolts by using the Allen keys.

    You can add some grease to the crank bolt, crank arm mates, and spindle. Place the crank bolt caps if they have and tighten them. Tighten the pinch bolts with a 5 mm Allen key, after that secure the crank.

    Now screw the pedals in the socket by turning the crank counterclockwise until they are tight enough. Check if you’re placing the right pedal in the right position; check the letter engraving on the pedal with ‘R’ and ‘L.’

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    How to Service Your Mountain Bike Cranks — Bike Hacks