⛓️ Chain Length Calculator
Enter drivetrain measurements to estimate the proper chain length before installation or replacement.
Measure from bottom bracket center to rear axle.
Minimum Links
86
Calculated base before rounding
Install Length
86 links
≈ 43.0 in / 109.2 cm
Slack Advice
Add one full link (inner + outer) beyond calculated minimum.
How to Use This Calculator
Measure chainstay
Use a tape measure from crank center to rear axle center.
Enter big-big gearing
Use largest front chainring and largest cassette sprocket.
Select bike type
Full-suspension frames need extra chain slack.
Round to even links
Chains must contain whole inner/outer pairs—use the rounded recommendation.
Formula
Links = 2 × (Chainstay × 2.54 ÷ 1) + (Chainring ÷ 4) + (Cog ÷ 4) + Adjustment
This adapts the big-big method popularized by manufacturers like Park Tool. Convert chainstay to inches, add quarter-teeth factors, then include 1 extra link for hardtails or 2 for full-suspension bikes.
Example
Chainstay 41 cm, 52T chainring, 28T cog → Links ≈ 2×(16.14×2)+52/4+28/4+1 ≈ 104. Add slack, round to 106 links.
Variables
- Chainstay: Frame length metric
- Teeth counts: Largest gear combo
- Adjustment: Extra slack requirement
Chain Sizing Tips
Proper chain length ensures smooth shifting and prevents drivetrain damage. Too-short chains strain the derailleur; too-long chains compromise tension.
Best Practices
- Always size with the shock/suspension fully extended on full-suspension bikes.
- Use master link pliers for quick installs and removal.
- Replace chains at 0.5–0.75% stretch to protect cassettes.
Advanced Considerations
- 1x drivetrains may use narrow-wide chainrings; follow manufacturer guidance for extra slack.
- DH bikes with idlers may require different calculations—use frame-specific instructions.
- E-bike chains often have higher tensile strength; ensure compatibility when replacing.
Frequently Asked Questions
Why must chain links be even?
Chains alternate inner and outer plates; you need complete pairs to install master links correctly.
Can I reuse old chains for measurement?
You can, but worn chains stretch. Measuring the old chain might yield inaccurate results—calculate fresh lengths instead.
How often should I replace chains?
Check with a chain wear gauge every 500–1,000 km. Replace at 0.5% wear for 11–12 speed systems.
Does drivetrain speed (10/11/12) affect length?
Length is independent of speed, but chain width differs. Ensure you purchase a compatible chain.
What about belt drives?
This calculator focuses on chain drivetrains. Belt drives require manufacturer-specific sizing.