You need a crank puller tool and an Allen wrench or socket wrench

Removing a crank arm requires two tools: a crank puller (a threaded tool that costs $15 to $40) and either an Allen wrench or socket wrench that fits your crank bolt. The crank arm is the lever that connects your pedal to the crankset, and it sits on a tapered square or splined shaft. You cannot straightforward pull it off—the taper is too tight. The puller works by threading into the crank arm while you turn a center screw that pushes against the shaft, gradually separating them.

Before you start, shift your chain to the smallest chainring and turn the crank so one arm points straight down. This gives you the most room to work. You will also need a clean, flat surface and about 15 to 20 minutes for the job.

Key Takeaways

  • A crank puller threads into the crank arm and uses a center screw to push the arm off the tapered shaft—you cannot remove it by force alone.
  • Loosen the crank bolt with an Allen wrench or socket wrench before you attach the puller, or the puller will not seat properly.
  • Turn the puller's center screw slowly and steadily; if you feel sudden resistance, stop and check that the puller is threaded straight into the arm.
  • Once the arm lifts free, remove the crank bolt completely and set it aside so you do not lose it.
  • Reinstalling the arm requires the same puller in reverse—thread the arm back onto the shaft, then tighten the crank bolt to 35 to 50 foot-pounds of torque.

Loosen the crank bolt before attaching the puller

The crank bolt holds the arm onto the shaft. It sits at the center of the crank arm, usually under a dust cap or cover. Pop off the dust cap with a flat screwdriver or your fingernail—it is not glued on, just pressed in. Underneath you will see the bolt head.

Use an Allen wrench (also called a hex key) or a socket wrench to loosen the bolt. Turn counterclockwise. Do not remove it completely yet—just loosen it enough that it turns freely by hand. This step matters because if the bolt is still tight, the crank puller will not seat properly and may strip the threads inside the crank arm.

Once the bolt is loose, you can remove it by hand and set it in a small container so you do not lose it. Wipe away any dirt or grease from the crank arm opening with a clean rag.

Thread the crank puller into the crank arm

The crank puller has two parts: an outer sleeve that threads into the crank arm, and an inner screw that pushes against the shaft. Hold the puller by the outer sleeve and thread it clockwise into the crank arm opening where the bolt was. Turn it by hand until it is snug—you should feel slight resistance, but you should not need a wrench yet.

Check that the puller is going in straight. If it feels crooked or binds, back it out and start again. A crooked puller will strip the threads and ruin the crank arm. Once the outer sleeve is hand-tight, use a wrench to turn it another quarter turn. It should be firm but not over-tightened.

Turn the center screw to separate the arm from the shaft

The center screw of the puller sticks out from the middle. Use an Allen wrench or socket wrench that fits the screw head. Turn it clockwise slowly and steadily. You will feel resistance as the screw pushes against the shaft and the arm begins to lift.

Keep turning. After a few full rotations, you should see the crank arm start to move away from the bike frame. If you feel a sudden hard stop or grinding, stop when ready. This usually means the puller is not seated straight. Back out the center screw, check that the outer sleeve is still threaded straight, and try again.

Continue turning until the crank arm comes free. It will usually pop off suddenly. Remove the puller from the crank arm and set both aside.

Remove the crank bolt and inspect the shaft

If you have not already, unscrew the crank bolt completely and remove it. Wipe the tapered shaft with a clean, dry rag. Look for any dirt, corrosion, or damage. If the shaft is rusty or pitted, you may want to clean it lightly with fine steel wool or a wire brush before reinstalling the arm.

Check the inside of the crank arm where it sat on the shaft. It should be clean and dry. If you see corrosion or buildup, wipe it out with a rag. Do not use water or oil—you want a dry fit so the taper seats properly when you reinstall.

Reinstall the crank arm in reverse order

Slide the crank arm back onto the shaft. It should slide on smoothly without force. If it binds or feels stuck, pull it back off and check for dirt or damage on the shaft or inside the arm.

Once the arm is on the shaft, insert the crank bolt and tighten it by hand first. Then use your wrench to tighten it to between 35 and 50 foot-pounds of torque. If you do not have a torque wrench, tighten it firmly but do not over-tighten—you should not need to strain. A bolt that is too tight can crack the crank arm; one that is too loose will let the arm slip.

Replace the dust cap by pressing it back into the opening. Spin the crank arm by hand to make sure it turns freely and does not wobble. If it wobbles, the arm may not be seated all the way. Remove the bolt, slide the arm off, and try again, making sure the shaft and arm are both clean and dry.

Common mistakes and how to avoid them

The most common mistake is trying to force the arm off without a puller. This will damage the taper and make the arm unusable. Always use a puller—it is a one-time purchase that will last for years.

The second mistake is threading the puller in crooked. Take your time and make sure it goes in straight. If you feel binding or resistance that does not ease as you turn, stop and start over.

The third mistake is over-tightening the crank bolt on reinstall. Tighten it firmly, but if you do not have a torque wrench, err on the side of slightly loose rather than too tight. You can always tighten it more later if it slips.

Finally, do not lose the crank bolt. It is small and straightforward to misplace. Put it in a container or bag as soon as you remove it, and keep it nearby while you work.

Frequently Asked Questions

Can I remove a crank arm without a puller?

No. The crank arm is held on by a tapered fit, and pulling or prying on it will damage the taper and the arm. A crank puller is the only safe way. They are inexpensive and reusable, so it is worth buying one if you plan to work on your bike again.

What size crank puller do I need?

Most modern bikes use a crank puller with a 14 mm or 15 mm outer thread. Check your bike's manual or take a photo of your crank arm to a bike shop and they can tell you which size fits. Universal pullers that fit multiple sizes also exist, though they are less common.

How tight should the crank bolt be?

Between 35 and 50 foot-pounds of torque is the standard range for most bikes. If you have a torque wrench, use it. If not, tighten the bolt firmly until you feel solid resistance, then stop. Do not crank on it with all your strength.

What if the crank arm will not come off even with the puller?

Stop turning and let the bike sit for an hour. Corrosion or a very tight fit may need time to release. You can also explore a penetrating oil like WD-40 around the base of the arm where it meets the shaft, wait 30 minutes, and try again. If it still will not budge, take the bike to a shop—forcing it further risks breaking the puller or the arm.

Do I need to replace the crank bolt after removal?

No, the bolt is reusable. Wipe it clean and reinstall it. If the bolt is bent, stripped, or damaged, replace it with one of the same size and length. A bike shop can match it for you if you bring the old bolt.