motorcycle
Gear ratio
Combine motorcycle primary reduction, selected transmission gear and chain final drive to calculate overall reduction and theoretical road speed.
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MOTORCYCLE CALCULATORMotorcycle Chain Length
Motorcycle Chain Length
Calculator
Estimate motorcycle chain link count from pitch, sprocket teeth and center distance, with an even-link selection and a revised center-distance estimate.
Your setup
teeth
Range: 6.00–250 teethteeth
Range: 6.00–300 teethin
Enter pin-to-pin pitch; chain width and strength are separate specifications.in
Range: 0.79–196.85 inYour results
CalculatedCalculated chain pitches106.19pitches
Selected even link count108links
Selected chain length67.50in
Revised center distance24.19in
Each pitch corresponds to one link in the count. Rounding changes the center distance needed to fit the chain.
READ THE ASSUMPTIONS
Two-sprocket open-drive approximation only. Excludes tensioners, suspension travel, wear, chain sag and offset links. Confirm fit and manufacturer instructions before ordering.
THE FORMULA
How the calculation works
We use the standard chain-length approximation for an open drive with two sprockets.
x = C/p; L ≈ 2x + (N₁+N₂)/2 + (N₂−N₁)²/(4π²x); selected links = 2 × ceil(L/2)Where:
- L = chain length in pitches
- C = shaft center distance
- p = chain pitch, in the same unit as C
- N₁ = front / driving sprocket teeth
- N₂ = rear / driven sprocket teeth
Front sprocket N₁ teeth
Rear sprocket N₂ teeth
← C: Shaft center distance →
A Worked Example
With equal 20-tooth sprockets, 0.5-inch pitch and 10-inch centers, x = 20 and L = 40 + 20 = 60 pitches. The selected chain is 60 links, or 30 inches.
What Your Result Means
Each pitch corresponds to one link in the count. Rounding changes the center distance needed to fit the chain.
Assumptions & Limitations
Two-sprocket open-drive approximation only. Excludes tensioners, suspension travel, wear, chain sag and offset links. Confirm fit and manufacturer instructions before ordering.
Common Mistakes
Do not use roller diameter as pitch or assume pitch alone establishes chain compatibility.
Questions about this calculation
Which values should I enter?
Use the same unit for pitch p and center distance C. Do not use roller diameter as pitch or assume pitch alone establishes chain compatibility.
How should I interpret the result’s precision?
Displayed results are rounded for readability. Intermediate calculations retain floating-point precision; extra displayed decimals do not improve your input accuracy.
Can I use metric units?
Yes. Select Metric above the calculator to convert your inputs. Results always state their units. Tire-size designations keep their conventional mm and inch units.
Does this include a tensioner or idler?
No. This approximation models an open drive with two sprockets. A tensioner or idler changes the chain path and needs its own geometric analysis.
What if my chain length is between even links?
The tool rounds up to the next even pitch count and estimates the revised shaft spacing. Check available adjustment and actual fit before selecting a chain.
Method, sources & relevant guides
Two-sprocket chain approximation and even-pitch selection. Sprocket geometry is independently derived from the regular polygon chord.
Renold — Transmission chain installation & designer guideMethod documentation updated October 18, 2026. Independent professional review has not been claimed. Read the calculation and review policy.