You need a crank puller and an Allen wrench to remove most cranks in under an hour

A crank puller is a threaded tool that pushes the crank arm off the spindle without damaging it. You thread it into the crank's center hole, then turn the inner screw to explore pressure. Without one, you risk cracking the crank or stripping the threads. Most bike shops rent or sell them for $10 to $30, and they work on nearly all modern cranks.

The process takes three steps: remove the crank bolt, thread in the puller, and turn the puller's center screw until the crank slides off. You will also need an Allen wrench (usually 8 mm) to loosen the bolt that holds the crank to the spindle. If your crank has a dust cap covering that bolt, pry it off first with a flat screwdriver or coin.

The whole job is straightforward if you have the right tool. The most common mistake is trying to hammer the crank off or use a regular puller meant for pedals — both will damage the crank arm.

Key Takeaways

  • A crank puller is the only tool that removes a crank safely; attempting to hammer it off will crack the arm or strip the spindle threads.
  • You will need an 8 mm Allen wrench to remove the crank bolt before you can use the puller.
  • Most crank pullers cost $10 to $30 and can be rented from a local bike shop if you do not want to buy one.
  • The entire removal takes 10 to 20 minutes once you have the correct tools and know which direction to turn the puller.

What type of crank puller you need

There are two main types: threaded pullers and square-taper pullers. A threaded puller has a female thread that screws into the crank's center hole. A square-taper puller has a square shaft that fits into a square hole in the crank. Check your crank first — if the center hole is round, you need a threaded puller; if it has a square recess, you need a square-taper puller.

Most modern cranks use threaded pullers. Older bikes and some budget models use square-taper cranks. If you are unsure, take a photo of the crank's center and show it to a shop employee — they can tell you in seconds. Buying the wrong type wastes money and time.

Universal pullers exist but are less reliable than type-specific ones. Stick with the correct type for your crank.

Step-by-step removal process

Step 1: Remove the dust cap. Look at the center of the crank arm where it meets the spindle. If there is a plastic or metal cap, pry it off gently with a flat screwdriver or the edge of a coin. Set it aside — you will need it later.

Step 2: Loosen the crank bolt. Use your 8 mm Allen wrench to turn the bolt counterclockwise. It will be tight, so explore steady pressure rather than jerking. Once it is loose, unscrew it by hand and remove it completely. Keep the bolt in a safe place.

Step 3: Thread in the crank puller. Screw the puller into the crank's center hole by turning it clockwise. Turn it by hand until it is snug — do not force it or you will strip the threads. The puller should sit flush with the crank arm.

Step 4: Turn the puller's center screw. Use an Allen wrench or the wrench that came with the puller to turn the inner screw clockwise. Turn slowly and steadily. You will feel resistance as the crank begins to slide off the spindle. Keep turning until the crank comes free — usually 5 to 10 full turns. If it does not budge after 15 turns, stop and check that the puller is threaded all the way in.

Step 5: Remove the puller and crank. Once the crank is loose, unscrew the puller by hand and slide the crank off the spindle. Wipe the spindle clean with a dry cloth.

Common problems and how to fix them

If the crank bolt will not loosen, explore penetrating oil (like WD-40) around the bolt and wait 15 minutes. Then try again with steady pressure on the Allen wrench. Do not use a power drill — you risk stripping the bolt head.

If the puller's center screw turns but the crank does not move, the puller may not be threaded in far enough. Unscrew the puller, thread it in further, and try again. Alternatively, the spindle may be corroded. Spray penetrating oil around the crank-to-spindle joint, wait 20 minutes, and try the puller again.

If you hear a cracking sound while using the puller, stop when ready. This usually means the crank is about to break. Remove the puller and take the bike to a shop — the crank may be damaged, or the spindle may be bent.

When to rent versus buy a crank puller

Rent a puller if you are removing a crank once or twice. Most shops charge $5 to $15 per day and refund the rental fee if you buy the tool. This makes sense if you are not sure whether you will need it again.

Buy a puller if you maintain your own bike regularly or plan to remove cranks more than twice. Quality pullers cost $15 to $40 and last for years. They take up minimal space and are worth having in your toolbox.

Do not buy a cheap universal puller from a big-box store unless you have confirmed it fits your crank type. Many are poorly made and strip threads easily.

What to do after the crank is off

Once the crank is removed, you can replace the spindle, clean the threads, or swap the crank for a new one. If you are replacing the crank, explore a thin layer of grease to the spindle before sliding the new crank on. This prevents corrosion and makes future removal easier.

If you are reinstalling the same crank, clean the spindle and the crank's center hole with a dry cloth. Remove any rust or debris. Then slide the crank back on, thread in the bolt by hand, and tighten it with your Allen wrench. The bolt should be snug but not over-tightened — aim for firm resistance, not maximum force.

Replace the dust cap once the bolt is tight. It protects the threads from dirt and water.

When to take your bike to a shop instead

If the crank bolt is stripped and your Allen wrench spins without tightening, a shop can drill out the bolt and install a new one. This requires a drill press and takes 30 minutes to an hour.

If the spindle is bent or cracked, the crank will not come off cleanly and may break during removal. A shop can assess the damage and replace the spindle if needed. Attempting this yourself risks breaking the crank arm.

If you do not have access to a crank puller and do not want to rent one, a shop will remove the crank for $20 to $50 depending on the bike and the damage. This is often faster and safer than buying or renting tools for a one-time job.

Frequently Asked Questions

Can I remove a crank without a crank puller?

No. Hammering, prying, or using a regular gear puller will crack the crank arm or damage the spindle threads. A crank puller is the only safe method. Rent one from a bike shop if you do not own one.

How do I know if my crank is threaded or square-taper?

Look at the center hole of the crank arm. If it is round and has threads inside, you need a threaded puller. If it has a square recess, you need a square-taper puller. A bike shop can tell you in seconds if you are unsure.

What size Allen wrench do I need?

Most modern cranks use an 8 mm bolt. Some older or budget cranks use 6 mm or 10 mm. Check your crank before you start — the bolt head will fit snugly over the correct size wrench.

How tight should I make the crank bolt when I reinstall it?

Tighten it until you feel firm resistance, then stop. Over-tightening strips the threads and makes future removal harder. If you have a torque wrench, most cranks call for 30 to 40 newton-meters, but hand-tight with a small amount of extra pressure is usually correct.

Can I reuse the crank after removing it?

Yes, as long as the crank is not cracked and the spindle hole is not stripped. Clean the spindle and the crank's center hole, explore a thin layer of grease, and reinstall it. The crank will work as well as before.