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How to Tighten Bike Crank? – A Step-by-Step Guide

Written by Gary Johnson / Fact checked by Henry Speciale

how to tighten bike crank

There’s no question that loose bike cranks can be a big headache. Not only does it give you an uneasy feeling but it’s also very unsafe when riding your bike.

So if you can sense a wobbly crank arm during your ride, then that’s your sign to go check it up & do some fixing.

 In this article, we’ll teach you how to tighten bike crank to ensure that your bike ride is safe & comfy.

Here’s what you need to do.

Step-by-step to Tighten Bike Crank


What to preparetighten-crank-on-bike

  • Wide-bladed slotted screwdriver/hex bolt
  • Wrench
  • Hammer or mallet

Tighten bicycle crank

There are different types of cranksets for every bicycle, but here is the common way to do so.

Step 1: Fully loosen the crank


You can use your finger if it’s totally loose or you can use a tool like a wrench to expedite the process.

If your bike crank has reversed threads, turning it clockwise will loosen it, and turning it counterclockwise will tighten it.

Step 2: Remove the nut


Simply remove the nut using your hands then move the washer that you’ll find right under the nut.

Step 3: Insert your screwdriver inside the crevice area or areas of your bike’s crank bolt.


The crevice area will be evident as soon as you remove the washer. This crevice area appears like a straight slit across the bolt where your flathead screwdriver can fit perfectly.

Step 4: Begin to tighten crank bolt by turning it counterclockwise


Turn the bolt until it’s no longer able to turn. This ensures that it’s already tightened. Depending on your bike’s model, some may need a hammer to gently tap the screwdriver to move it.

Step 5: Insert back the washer and the nut


Put the washer first and ensure that it properly fits.

Check your washer & look for the tiny protruding nub. Fit it into the small crevice found in the housing of the crank. This should allow the washer to be locked in.

Insert the nut next and turn it clockwise until it’s fully tightened. Use your wrench or your slip joint pliers to further tighten it.

Tighten the Mountain Bike Crank


What to prepareremove-crank-arm-from-bike

  • Hex bolt
  • Hammer or mallet
  • Flathead screwdriver

Tighten bike crank for mountain bikestool-to-tighten-bike-crank

Mountain bikes often have larger cranks than regular bikes and utilize a hex bolt in the crank arm. It is an essential tool to tighten bike crank for mountain bikes.

Here’s what you need to do.

  • Step 1: If your bike model has a plastic dust cap that masks the bolt, remove it first using your flathead screwdriver.

Insert the flathead screwdriver into the splines of the dust cap. Begin to turn to the left until it is loose.

If your bike doesn’t have a dust cap, skip, then proceed to step 2.

  • Step 2: Loosen up the hex bolt.

With this step, use your fingers or wrench, and rotate the hex bolt counterclockwise. This shouldn’t take long, as the hex bolt is probably already loose.

  • Step 3: Grab your screwdriver and insert it between the crevices of the bike crank bearing.

Now, simply turn the hex bolt counterclockwise until you feel that it starts to get harder to turn.

This means that it is semi-tightened, but you want it to be as tight as possible to avoid your bike crank slipping after multiple rides.

  • Step 4: To fully and securely tighten crank on bike, take hold of your mallet or hammer and gently tap the head of the screwdriver. At the same time, it is placed inside the crevices of the bearing.

In doing this, you will notice that the bearing is slowly moving clockwise as you tap. Adjust your angles to your preference and where it’s most comfortable for you.

Check your bike. If it no longer feels like a bike crank loose, then it’s good to go.

Why Do Bike Cranks Wobble?


Cranks often wobble due to mechanical issues that involve bicycle crank bearings loose or a worn-out bottom bracket.

  • The bicycle crank having loose bearings is the most typical cause of a wobbly crank. We have already laid out the many ways for tightening the bike crank, so it all depends on your model or which you prefer is easier for you to follow!
  • For a loose bottom bracket, what you need to do is to remove the crank arm from the bike and secure back the bottom bracket firmly.
  • If it’s a worn-out bottom bracket that makes your bike crank slipping, your only choice is to replace the bearings.

Frequently Asked Questions


How to fix a bike crank that fell off?

If your exercise bike crank arm loose and falls off, fixing it isn’t too different from tightening it. With the simple steps above, you can fix a bike crank that fell!

All you have to do is re-tighten the cranks using the procedure above. Remember to reattach the crank and tighten it to the bottom bracket.

How to remove the crank arm from bike?

You can remove a crank arm either with a puller or without.

If you don’t have a puller, here’s what you need to do. You may use a spindle in this process.

  1. First, detach the bolt by rotating it clockwise.
  2. Then, pedal the pedals until they become completely loose.
  3. Next step, you will need a hammer and wood. Point the wood towards the crank arm’s center. Softly hit the hammer as it knocks onto the wood.

If you do have a puller, do the following:

Determine whether the type of bike you have is a two-piece compression slotted crank or a three-piece crank.

For a two-piece compression slotted crank:

  1.  Begin to loosen the left crank arm’s pinch bolts. Do not lose them entirely.
  2. Use any tool that can detach and remove the plastic pre-load cap. Use your fingers to remove the left crank connected to its spindle.

For a three-piece crank:

  1. Use an 8mm Allen wrench to remove the bolt. Take your wrench to turn and detach the bolts.
  2. Insert the larger side of your crank puller into the same area where the bolts have been detached in the crank hole.
  3. Begin to turn the crank puller up until you can now feel the edges.
  4. Rotate the puller’s smaller bolt two or three times using a 15mm wrench. Do this while the crank puller is still placed inside.
  5. Continue the procedure until the cranks loosen up and become unhitched.


Troubleshooting and fixing your bike is crucial. And now that you know how to fix a loose bike pedal crank, you’re assured that if worse comes to worst, you know what to do & how to handle it.

The best part about this is when you know how to tighten bike crank, you won’t have to worry about the hassle of going to a repair shop.

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