How to Remove a Mountain Bike Crank: A Simple Guide

Last Updated on October 25, 2026 by Jaxon Mike

Removing the crank from your mountain bike is a manageable DIY task. You’ll need a few specific tools, like a crank puller and an Allen wrench. Knowing the right steps makes this job much easier for you.

This process is essential for maintenance, repairs, or upgrades. Whether you’re swapping out worn-out pedals or looking to install a new drivetrain, understanding how to remove your cranks properly saves time and money. It ensures your bike’s components are handled with care.

• Gather your tools: crank puller, Allen wrenches.
• Identify your crank type.
• Follow specific removal steps.
• Keep parts organized.
• Reassembly is the reverse.

Let’s walk through exactly how to remove your mountain bike crank, step by step.

Getting Your Mountain Bike Cranks Off

Removing the crankset from your mountain bike might sound a little intimidating, but it’s a task you can totally tackle yourself. We’ve found that having the right tools makes all the difference. You’ll need a crank puller and a good set of Allen wrenches. Knowing your crank type is also key to success.

Understanding Your Crankset Type

Before you start pulling, it’s important to know what kind of crankset you have. This determines the exact tools and process you’ll use. Most modern mountain bikes use either a square taper, splined (like ISIS or Octalink), or a Hollowtech II/GXP style. Each has a different way the crank arm attaches to the bottom bracket spindle.

Square Taper Cranks

These are older but still common on many entry-level bikes. The crank arm slides onto a tapered spindle with a square end. You’ll likely see a bolt on the outside of the crank arm that holds it in place. For these, you need a specific square taper crank puller. It has a threaded end that screws into the crank arm’s threaded hole and another part that pushes against the bottom bracket spindle.

Splined Cranks (ISIS, Octalink)

These look a bit like square taper but have grooves, or splines, on the spindle and inside the crank arm. This design offers a stronger connection. The removal process is similar to square taper. You’ll use a crank puller that’s designed for splined interfaces. Make sure you get the one that matches your specific spline type (ISIS or Octalink), as they are not interchangeable. The crank puller will thread into the crank arm and push against the bottom bracket spindle.

External Bearing Cranks (Hollowtech II, GXP, DUB)

These are the most common on mid- to high-end mountain bikes today. The bottom bracket bearings are actually housed outside the frame. The crankset typically consists of a spindle permanently attached to the drive-side crank arm and a non-drive crank arm that slides onto the spindle. There are usually one or two bolts on the non-drive side crank arm that clamp it to the spindle. Removing these often involves an Allen wrench to loosen bolts and sometimes a specific tool to pry the crank arm off. We found that some manufacturers provide special tools for their specific systems, like Shimano’s Hollowtech II.

Essential Tools You’ll Need

Having the right tools makes this job much smoother. Don’t try to improvise too much here, as you could damage your bike’s components. We’ve found that investing in a few key tools is well worth it for any home mechanic.

The Crank Puller is Your Best Friend

This is the most critical tool. As we’ve seen, there are different types. You absolutely must get the correct crank puller for your crankset’s interface. Using the wrong one can strip threads or damage the crank arm. Most crank pullers have two parts: a body that screws into the crank and a spindle that pushes against the bottom bracket axle. Make sure it’s compatible with your system.

Allen Wrenches (Hex Keys)

These are needed for most modern cranksets, especially external bearing types. You’ll need a set with various sizes, usually from 4mm to 8mm. Some crank bolts are quite tight, so having a good quality wrench that fits well is important. A longer wrench provides better leverage.

Other Helpful Items

A rag or shop towel is always handy for wiping away dirt and grease. Some gentle degreaser can also help clean parts before reassembly. You might also want a small mallet or rubber hammer if a crank arm is particularly stubborn, but use this very sparingly. A torque wrench is essential for reinstallation to ensure proper tightness. We found that proper torque prevents creaking and damage.

Step-by-Step Crank Removal Process

Let’s break down the removal process. Remember, the exact steps can vary slightly based on your crankset, so always check your manufacturer’s instructions if possible. We suggest taking pictures as you go; it helps a lot with reassembly.

Step 1: Preparation and Bolt Removal

First, clean the area around your crankset and bottom bracket. This prevents dirt from getting into your bottom bracket. Locate the bolts that hold the crank arm onto the spindle. For square taper and splined cranks, this is usually a single bolt on the outside of the crank arm. For external bearing types, it’s typically one or two bolts on the inside of the non-drive side crank arm. Use your Allen wrench or appropriate tool to loosen and remove these bolts. Keep them somewhere safe!

Step 2: Engaging the Crank Puller (For Square Taper/Splined)

If you have a square taper or splined crank, you’ll now use your crank puller. First, carefully screw the outer body of the crank puller into the threaded hole on the crank arm. It should thread in smoothly. Don’t force it. Once it’s snug, you’ll begin to turn the inner spindle part of the crank puller. As you turn this inner spindle, it will push against the bottom bracket spindle and force the crank arm off. You’ll feel it start to loosen. Keep turning until the crank arm is free.

Step 3: Removing External Bearing Cranks

For external bearing systems, the process is different. After removing the securing bolts, the non-drive side crank arm may slide off easily. Some systems have a pre-load adjustment ring that needs to be loosened or removed first. If the crank arm doesn’t slide off, you might need a special tool to gently pry it off or tap it with a rubber mallet. We’ve found that gentle persuasion is usually enough. Be careful not to damage the bottom bracket or the crank spindle.

Step 4: Removing the Second Crank Arm (Drive Side)

Once the non-drive side crank arm is off, you’ll usually find that the drive-side crank arm and spindle are attached. For most external bearing systems, this entire unit will slide out of the bottom bracket shell. For older square taper or splined systems, you might need to remove a lockring on the drive side before the spindle can be removed. If you’re only replacing pedals or the non-drive crank, you might not need to remove the drive side. But for bottom bracket maintenance, you’ll remove the entire crankset.

Here’s a quick checklist to keep you on track:

• Check your crank type: Square taper, splined, or external.
• Gather the correct crank puller and Allen wrenches.
• Clean the crank and bottom bracket area.
• Remove crank arm bolts carefully.
• Use the crank puller correctly if applicable.
• Keep all parts organized for reassembly.

Conclusion

You’ve now got a solid understanding of how to remove your mountain bike’s crankset. We’ve seen that identifying your crank type is the first key step. Having the correct tools, especially the right crank puller, makes the whole process much smoother. By following these steps carefully and keeping your parts organized, you’re well-prepared for maintenance or upgrades. Don’t hesitate to consult your bike’s manual if you encounter anything unusual. Now, you can confidently tackle this task and keep your bike running smoothly!

Frequently Asked Questions

How do I know which type of crank puller I need?

You need to identify your crankset interface first. Square taper, splined (like ISIS or Octalink), and external bearing systems all require different types of crank pullers. We recommend checking your bike manufacturer’s specifications or carefully examining the crank spindle and arm connection to determine the correct tool. Our guide to the best mountain bike crank arms can help you identify the correct interface.

What if my crank arm is really stuck?

If your crank arm is stubborn, ensure you’ve removed all securing bolts. For external bearing types, double-check any pre-load rings. Sometimes, a gentle tap with a rubber mallet on the crank arm (away from the frame) can help break it free. Never force it excessively, as you could damage components.

Can I remove my crank without a crank puller?

For square taper and splined cranks, a specialized crank puller is essential. Trying to force these off without one can severely damage the bottom bracket spindle and crank arm threads. For some external bearing systems, a specific prying tool might be used, but we found that the manufacturer’s tool or a proper crank puller is always the safest bet.

Do I always need to remove both crank arms?

Not necessarily. If you’re just replacing pedals or need access to the non-drive side crank arm, you might only need to remove that one. However, if you’re servicing the bottom bracket or doing a full drivetrain overhaul, you’ll likely need to remove both arms.

What’s the most common mistake people make when removing cranks?

One of the most frequent errors we’ve observed is using the wrong type of crank puller. This can strip the threads on your crank arm or bottom bracket spindle, leading to costly repairs. Always confirm your crankset type before selecting your tool.