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Cycling••7 min read

How To Shorten A Bike Chain With A Chain Tool

Step-by-step guide to shortening a bike chain using a chain tool. Learn to remove links safely and reconnect your chain properly.

To shorten a bike chain, count the links you need to remove, place the chain in the chain tool, push the pin almost all the way out while leaving it connected to the outer plate, then remove the section and rejoin with a quick link or chain pin.

Most new chains come longer than needed and must be shortened to fit your bike. This guide walks you through the process safely and correctly.

Tools and Materials Needed

Essential

  • Chain tool (also called chain breaker)
  • New chain (or existing chain if just resizing)
  • Quick link (master link) for reconnection

Helpful

  • Chain hook or wire (to hold chain during work)
  • Rag or paper towels (chains are messy)
  • Needle-nose pliers (for quick link installation)
  • Ruler or measuring tape (to verify link count)

Before you start, understand chain anatomy:

  • Inner link: Has two inner plates and two rollers
  • Outer link: Has two outer plates connecting the inner links
  • Full link: One inner + one outer (1 inch / 25.4mm)
  • Half link: One inner OR one outer (0.5 inch / 12.7mm)

Important Rules

  • Chains must have an even number of links to connect
  • Standard chains connect outer plate to outer plate via quick link
  • Remove links in pairs (2, 4, 6, etc.) to maintain proper ends

Step-by-Step: Shortening Your Chain

First, calculate the correct chain length:

Example:

  • Your chain has 116 links
  • Calculator says you need 110 links
  • Remove 6 links

Step 2: Count and Mark the Cut Point

  1. Lay the chain flat on a clean surface
  2. Count from one end to find where to cut
  3. Mark the link with tape or a marker
  4. Double-check your count

Pro tip: Count half-links (each plate pair) rather than full links for accuracy.

Step 3: Prepare the Chain Tool

Most chain tools have two positions:

  • Driving position: For pushing pins out
  • Loosening position: For adjusting stiff links (if applicable)

Make sure you're using the correct position for pin removal.

Step 4: Position the Chain in the Tool

  1. Place the chain in the driving cradle
  2. Align the tool's driving pin with a chain pin
  3. The chain should be stable and not able to move sideways

Step 5: Push the Pin Out

For Quick Link Reconnection (Recommended):

  1. Turn the chain tool handle clockwise slowly
  2. Push the pin completely through and out
  3. The chain will separate into two pieces
  4. Save the pushed-out piece for future use

For Pin Reconnection (Shimano HG chains):

  1. Turn the handle slowly
  2. Push the pin almost all the way out
  3. Leave it barely connected to the outer plate
  4. This allows reconnection (though not recommended for repeated use)

If removing multiple links:

  1. Repeat the pin removal at the second cut point
  2. Remove the section of chain between cuts
  3. You should now have two chain ends ready to connect

Step 7: Reconnect the Chain

Using a Quick Link (Master Link):

  1. Place one half of the quick link on each chain end
  2. Thread both ends through the rear derailleur and around the gears
  3. Connect the quick link halves by:
    • Pulling the pins through the opposing holes
    • Pulling the chain taut to snap it together
  4. Verify the link is fully engaged

Using a Connecting Pin (Shimano):

  1. Align the chain ends
  2. Insert the special connecting pin from inside to outside
  3. Use the chain tool to push the pin through
  4. Break off the guide tip with pliers
  5. Check that the pin sits flush with both plates

Step 8: Check the Repair

  1. Rotate the chain through the drivetrain
  2. Check for stiff links (link doesn't bend smoothly)
  3. If you find a stiff link, flex it side-to-side gently or use the chain tool's loosening position
  4. Test shift through all gears

Tips for Common Chain Types

Shimano Chains

TypeReconnection Method
HG (9/10/11-speed)Use Shimano connecting pin
HG (12-speed)Quick link only
Older chainsEither method

Note: Shimano recommends their specific connecting pins, but compatible quick links also work.

SRAM Chains

TypeReconnection Method
All modern SRAMPowerLock or PowerLink (quick link)
12-speedPowerLock (single use)
11-speed and belowPowerLink (reusable)

KMC Chains

TypeReconnection Method
All KMC chainsMissing Link (quick link)

KMC Missing Links are generally reusable for several uses.

Campagnolo Chains

TypeReconnection Method
10/11/12-speedCampagnolo specific pins
Ekar (13-speed)Campagnolo specific pins

Note: Campagnolo chains require their proprietary connecting system.

Common Mistakes to Avoid

Wrong: Removing 3 links (chain ends won't match) Right: Removing 2 or 4 links (outer plates meet outer plates)

Wrong: Pin falls out completely on pin-reconnection style Right: Leave pin barely attached if planning to push back through

3. Reusing Pushed Pins

Wrong: Pushing the same pin out and back multiple times Right: Use a new connecting pin or quick link each time

Wrong: Assuming the quick link clicked into place Right: Pull chain firmly and visually verify lock position

5. Cutting in the Wrong Place

Wrong: Cutting at a quick link or damaged section Right: Cutting at a standard link, avoiding any wear points

If your reconnected link is stiff (doesn't bend as smoothly as other links):

Method 1: Hand Flexing

  1. Grip the chain on either side of the stiff link
  2. Flex the chain side-to-side
  3. Repeat until the link moves freely

Method 2: Chain Tool Loosening Position

  1. Place the stiff link in the tool's outer cradle (if available)
  2. Turn the handle slightly to push the pin
  3. A tiny movement often frees the link

Method 3: Pliers

  1. Grip the stiff link with pliers
  2. Gently twist to loosen
  3. Be careful not to damage the plates

Safety Considerations

  • Wear eye protection when pushing pins (they can spring out)
  • Keep hands clear of the chain tool mechanism
  • Don't over-tighten the tool or you may damage the chain
  • Test ride carefully after any chain work

When to Start Fresh with a New Chain

Consider a new chain if:

  • Current chain shows 0.5% or more wear
  • Links are damaged or bent
  • Chain has been repaired multiple times
  • Rust or corrosion is present

Disclaimer: Information provided by this site is for educational purposes only and is not intended to be a substitute for professional medical advice specific to the reader's particular situation. The information is not to be used for diagnosing or treating any health concerns you may have. The reader is advised to seek prompt professional medical advice from a doctor or other healthcare practitioner about any health question, symptom, treatment, disease, or medical condition.