The bicycle crank is a crucial component that connects the pedals to the drivetrain, enabling you to propel your bike forward. However, there may come a time when you need to remove the crank, whether for maintenance, repairs, or upgrades. Fortunately, removing a bike crank is a relatively straightforward process with the right tools and know-how. This comprehensive guide will provide you with step-by-step instructions on how to safely and effectively remove your bike crank.
Before embarking on this task, gather the necessary tools, including a crank puller, a 5mm Allen key, and a chain whip or lockring tool. It’s also advisable to secure your bike in a stable position using a bike stand or leaning it against a wall. Begin by removing the pedals using the 5mm Allen key, then proceed to detach the chainrings from the crank using the chain whip or lockring tool. Next, insert the crank puller into the crank arm and tighten it until the crank loosens from the bottom bracket.
Once the crank is loose, carefully remove it from the bottom bracket. If it’s stuck, apply some penetrating oil and allow it to sit for a while before attempting to remove it again. Inspect the crank and bottom bracket for any signs of damage or wear, and clean them thoroughly before reassembling the components. Reinstalling the crank is essentially the reverse process of removal. Apply a small amount of grease to the threads of the bottom bracket, then insert the crank and tighten it using the crank puller. Finally, reattach the chainrings and pedals, and your bike will be ready to ride once more.
Safety Precautions
Before beginning any work on your bike, it’s crucial to prioritize safety. Follow these guidelines to minimize risks:
1. Eye Protection: Essential for Your Safety
Wear safety glasses or goggles to shield your eyes from flying debris or particles that may be released during the process. Even a small piece of metal can cause significant damage if it enters the eye. Opt for glasses that fit snugly and offer ample coverage to prevent any objects from slipping underneath. Remember, protecting your eyesight is paramount, so don’t compromise on this essential safety measure.
Avoid wearing loose-fitting clothing or jewelry that could get caught in moving parts, potentially causing injuries. Choose comfortable, form-fitting clothing that allows you to move freely and safely.
Use nitrile or latex gloves to protect your hands from grease, solvents, or sharp edges. Gloves provide an extra layer of protection against cuts and abrasions.
Ensure that your bike is securely supported on a stable workstand or upside down on a flat surface. This prevents it from falling and causing injury to yourself or others.
Equipment Preparation
Gather the necessary tools and materials before starting the task. This will ensure a smooth and efficient workflow:
- Chain whip
- Socket wrench or Allen key (size depends on crank type)
- Crankarms removal tool
- Penetrating oil (optional)
- Workstand or stable surface
If you encounter any stubborn bolts or components, applying penetrating oil can help loosen them. Spray or apply the oil to the affected area and allow it to penetrate for a few minutes before attempting to remove it.
Identifying Crank Types and Tools Required
Step 1: Identify Crank Type
Bike cranks come in various types, each requiring specific tools for removal:
- Square Taper Cranks: Common in older bikes, these cranks have a square-shaped axle that fits into a matching hole in the bottom bracket.
- Cottered Cranks: Similar to square taper cranks, cottered cranks use a cotter pin to secure the axle.
- Splined Cranks: Found on mid-range and high-end bikes, splined cranks have a series of teeth on the axle that engage with a grooved bottom bracket.
- ISIS Cranks: These cranks use a splined axle with a retaining ring to provide a secure connection to the bottom bracket.
- Octalink Cranks: Developed by Shimano, octalink cranks feature a spline-shaped interface with 8 notches, allowing for a lightweight and durable connection.
- Power Spline Cranks: Used on high-performance bikes, power spline cranks have a hexagonal-shaped axle that provides maximum torque transfer.
Step 2: Determine Necessary Tools
Once you’ve identified the crank type, gather the appropriate tools:
| Tool | Types of Cranks |
|---|---|
| Allen Key (Hex Wrench) | Square Taper, Cottered |
| Crank Puller | Square Taper, Splined, ISIS |
| Cotter Pin Remover | Cottered |
| Octalink Socket | Octalink |
| Power Spline Socket | Power Spline |
In addition, you may need a hammer, a penetrating lubricant, and a rag for cleaning.
Removing Pedals
Pedals are typically removed using a 15mm spanner or Allen key. Locate the bolt on the inside of the pedal arm, and turn it counterclockwise to loosen and remove the pedal. If the bolt is tight, you may need to use a pedal wrench for additional leverage.
Removing Chainring Bolts
Chainring bolts are typically removed using a 5mm Allen key or Torx wrench. Locate the bolts on the inside of each chainring, and turn them counterclockwise to loosen and remove them. Be careful not to overtighten the bolts when reinstalling them, as this can damage the chainrings.
Removing the Larger Chainring
In most cases, there will be two chainrings on a bike. The larger chainring is typically attached to the crank arm using four or five bolts. Follow the steps below to remove the larger chainring:
- Place the bike in a work stand or on a flat surface.
- Locate the bolts on the back of the larger chainring.
- Use a 5mm Allen key or Torx wrench to loosen the bolts counterclockwise.
- Once the bolts are loose, remove the chainring from the crank arm.
Removing the Smaller Chainring
The smaller chainring is typically attached to the larger chainring using two or three bolts. Follow the steps below to remove the smaller chainring:
- Locate the bolts on the back of the smaller chainring.
- Use a 5mm Allen key or Torx wrench to loosen the bolts counterclockwise.
- Once the bolts are loose, remove the smaller chainring from the larger chainring.
Loosening the Crank Arm Bolts
The crank arm bolts are usually tightened to a high torque, so you will need to use a high-quality wrench or socket to loosen them. If you do not have the proper tools, you can take your bike to a bike shop and have them loosen the bolts for you.
To loosen the crank arm bolts, follow these steps:
- Place the bike in a work stand or on a flat surface.
- Use a 8mm Allen wrench or socket to loosen the crank arm bolts. The bolts are usually located on the inside of the crank arms, near the bottom bracket.
- Loosen the bolts, but do not remove them completely.
- Gently tap the crank arms with a hammer or mallet to loosen them from the bottom bracket. If the crank arms are stuck, you can use a penetrating oil to help loosen them.
- Once the crank arms are loose, remove the bolts and pull the crank arms off of the bottom bracket.
| Bolt Size | Torque |
|---|---|
| 8mm | 35-45 Nm |
| 10mm | 50-60 Nm |
| 12mm | 65-75 Nm |
Using a Crank Puller for Extraction
A crank puller is a specialized tool designed to remove bike cranks effectively. Here’s a detailed guide on how to use one:
1. Safety Precautions
Before starting, ensure your bike is secure on a workstand or stable surface. Wear safety goggles and gloves to protect yourself from flying parts or injuries.2. Identify Crank Type
Determine the type of crankset you have. Common types include square taper, Octalink, ISIS Drive, and Hollowtech II. Each type requires a specific crank puller.
3. Remove the Bolt
Using an Allen key or wrench, loosen the bolt securing the crank arm to the spindle. Note that some cranksets may have a left-hand thread, so turn counterclockwise to loosen.
4. Attach the Crank Puller
Select the correct crank puller for your crankset type. Align the puller’s arms with the crank arm and spindle. Tighten the bolts to secure the puller into place.
5. Extract the Crank Arm
This step involves two methods depending on the crank puller type:
| Crank Puller Type | Extraction Method | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Two-Bolt Puller | Tighten both bolts evenly and simultaneously to force the crank arm off the spindle. | ||||||||||||||||||||||||||||||||||
| Three-Bolt Puller | Tighten the center bolt first to break the crank arm loose, then tighten the outer bolts to remove it completely. |
| Step | Instructions |
|---|---|
| 1. | Screw the crank arm puller into the threaded hole at the end of the crank arm opposite the chainring. Tighten it securely using a wrench. |
| 2. | Attach the puller arm to the crank arm puller and tighten it until it is snug against the bottom bracket. |
| 3. | Tighten the center bolt of the crank arm puller using a wrench. As you tighten, the puller arm will extend and gradually push the crank arm outwards from the bottom bracket. |
| 4. | When the crank arm is completely removed, release the center bolt and remove the crank arm puller. |
Safety Tips:
- Always wear safety glasses when using the crank arm puller.
- Do not overtighten the crank arm puller, as this can damage the components.
- If the crank arm does not come off easily, do not force it. Consult a bike mechanic for assistance.
Inspecting the Crank and Bottom Bracket
Assessing Crank Fit and Wear
Begin by examining the crank’s fit and alignment. Spin the cranks and observe any wobbling or side-to-side movement. Look for worn or damaged threads on the crank bolt that connects the arms to the bottom bracket spindle. Inspect the pedals and crank arms for cracks, bends, or other signs of stress.
Inspecting the Chainring Bolts
Next, check the chainring bolts. Ensure they are tight and secure. Any loose bolts can lead to uneven chain engagement, shifting issues, and potential chain drops.
Identifying Worn Bottom Bracket Bearings
Worn bottom bracket bearings can manifest in several ways:
| Symptom | Cause |
|---|---|
|
Grinding or noisy |
Worn or contaminated bearings |
|
Increased resistance when pedaling |
Excessive friction due to lack of lubrication or damaged bearings |
|
Side-to-side play in the crankset |
Severely worn or damaged bearings or spindle |
To confirm bearing wear, carefully lift the bike and support it on a workbench or stand. Grasp the crank arms and attempt to move them back and forth. Any noticeable play indicates a worn bottom bracket.
Removing the Non-Drive Side Crank Arm
The non-drive side crank arm is attached to the bike frame using a bolt that passes through the bottom bracket shell. To remove this crank arm, you will need the following tools:
- Chain whip
- Bottom bracket tool (specific to the type of bottom bracket on your bike)
- Allen key (if the crank arm is secured with an Allen bolt)
Follow these steps to remove the non-drive side crank arm:
- Position the bike: Flip the bike upside down and place it on a work stand or a sturdy surface.
- Secure the chain: Use a chain whip to hold the chain in place on the bottom bracket. This will prevent the chain from slipping off the chainring when you loosen the crank arm bolt.
- Locate the bottom bracket tool: Find the appropriate bottom bracket tool for your bike. This tool will fit into the bottom bracket shell and allow you to loosen the crank arm bolt.
- Loosen the crank arm bolt: Insert the bottom bracket tool into the bottom bracket shell and engage it with the crank arm bolt. Turn the tool counterclockwise to loosen the bolt.
- Remove the bolt: Once the bolt is loose, remove it completely using your fingers or an Allen key (if applicable).
- Wiggle the crank arm: Gently wiggle the crank arm back and forth while pulling it towards you. It should come loose from the bottom bracket spindle.
- Clean the threads: Clean the threads on the crank arm bolt and in the bottom bracket shell using a rag and solvent.
- Inspect the components: Carefully inspect the crank arm, bottom bracket spindle, and threads for any damage or wear. If you notice any irregularities, replace the affected component before reassembling the crankset.
Removing the Crank Arm Bolts
Now that the plastic cover and crank arm bolts are exposed, it’s time to remove them. For this step, you’ll need an Allen key or hex wrench that matches the size of the crank arm bolts. Insert the Allen key into the bolt and turn it counterclockwise to loosen it. Be careful not to strip the bolt or damage the threads.
Removing the Crank Arms
Once the bolts are loosened, you can gently pry the crank arms off the spindle. Use a rubber mallet or a soft-faced hammer and tap the crank arms from the back. Be careful not to hit the spindle directly, as this can damage it.
Cleaning the Crank System
With the crank arms removed, it’s time to clean the crank system. Use a degreaser or bike cleaner to remove any dirt, grime, or grease from the spindle, crank arms, and chainrings. You can use a toothbrush or a soft brush to get into the nooks and crannies.
Reassembling the Crank System
Before reassembling the crank system, apply a small amount of grease to the threads of the crank arm bolts and the spindle. This will help to prevent them from seizing in the future.
Align the crank arms with the spindle and slide them onto the spindle. Tighten the crank arm bolts using the Allen key or hex wrench, but don’t overtighten them.
Finally, replace the plastic cover and secure it with the screws.
Troubleshooting Tips:
If you’re having trouble removing the crank arms, try applying a penetrating lubricant to the bolts and letting it sit for a few minutes before trying to loosen them. If that doesn’t work, you may need to use a crank puller tool.
If you’re having trouble reassembling the crank system, make sure that the crank arms are aligned correctly with the spindle. If they’re not, it will be difficult to tighten the crank arm bolts.
| Tool | What it’s for |
|---|---|
| Allen key or hex wrench | Removing the crank arm bolts |
| Rubber mallet or soft-faced hammer | Removing the crank arms |
| Toothbrush or soft brush | Cleaning the crank system |
| Degreaser or bike cleaner | Cleaning the crank system |
Removing the Crank Arm Bolts
To remove the crank arm bolts, you will need a 6mm Allen key. Insert the Allen key into the bolt and turn it counterclockwise. The bolt should come loose relatively easily. If it is stuck, you may need to use a little force. Once the bolt is loose, you can remove it by hand.
Removing the Crank Arm
Once the crank arm bolts are removed, you can remove the crank arm. To do this, simply pull the crank arm straight off of the spindle. It may take a little bit of force to remove the crank arm, but it should come off relatively easily.
Tightening the Crank Arm Bolts
Tightening the Crank Arm Bolts and Final Adjustments
Once the crank arm is removed, you can tighten the crank arm bolts. To do this, insert the crank arm bolt into the spindle and turn it clockwise using a 6mm Allen key. Tighten the bolt until it is snug, but do not overtighten it. Once the bolt is tightened, you can install the crank arm.
Final Adjustments
Once the crank arm is installed, you may need to make some final adjustments. First, check to make sure that the crank arm is aligned properly. The crank arm should be parallel to the ground when the bike is in the riding position. If the crank arm is not aligned properly, it can cause the chain to rub on the frame or the pedals to hit the ground when you are riding. To adjust the alignment of the crank arm, simply loosen the crank arm bolts and rotate the crank arm until it is aligned properly. Once the crank arm is aligned, tighten the crank arm bolts.
Checking the Chainring Alignment
Once the crank arm is aligned, you should check the chainring alignment. The chainring should be aligned with the rear cogs. If the chainring is not aligned properly, it can cause the chain to skip or derail. To check the chainring alignment, simply shift the bike into the middle chainring and the middle rear cog. If the chainring is aligned properly, the chain will run smoothly over both the chainring and the rear cog. If the chainring is not aligned properly, you can adjust it by loosening the chainring bolts and rotating the chainring until it is aligned properly. Once the chainring is aligned, tighten the chainring bolts.
| Tool | Use |
|---|---|
| 6mm Allen key | Remove and tighten the crank arm bolts |
| Chainring wrench | Remove and tighten the chainring bolts |
How to Remove a Bike Crank
Removing a bike crank is a common task that may be necessary for repairs or maintenance. The process can vary depending on the type of crankset, but the general steps are as follows:
- Place the bike in a work stand or upside down on a stable surface.
- Identify the crank bolts, which are usually located at the ends of the crank arms.
- Use a hex key or socket wrench to loosen the bolts.
- Once the bolts are loose, use a crank extractor to remove the crankset.
- Clean the crank axle and threads before reinstalling the crankset.
People Also Ask
How do I know when it’s time to replace my crank?
There are a few signs that may indicate it’s time to replace your crank:
- Creaking or clicking sounds when pedaling
- Difficulty shifting gears
- Worn teeth on the chainrings
- Bent or cracked crank arms
Can I remove my crank without a crank extractor?
It is possible to remove a crank without a crank extractor, but it is not recommended. Using an extractor is the safest and most effective way to remove a crank, as it prevents damage to the crank axle and threads.
How can I prevent my crank from loosening?
There are a few things you can do to prevent your crank from loosening:
- Tighten the crank bolts to the correct torque using a torque wrench.
- Use thread locker on the crank bolts.
- Inspect the crank bolts regularly for tightness.
