Chain Length Calculator

LIGUORI DRAG RACING

Dial in your chain length

Move the sliders or enter your measurements. Chain length, sprocket layout, and axle adjustment options update instantly.

Measurement unitsUS Standard — inches Metric — millimeters Chain size420 428 520 525 530 630

Front sprocket teeth

Rear sprocket teeth

Sprocket center distance (in)

Measure directly from the center of the countershaft/front sprocket to the center of the rear axle. This is different from wheelbase. The starting values are an example—enter your own setup.

Reset example

Compare axle positions

Positive movement lengthens the center distance; negative movement shortens it. Choose a row to try that center distance in the calculator.

This estimates a two-sprocket drive without idlers using L = 2C/P + (front + rear)/2 + (rear − front)²P/(4π²C). Links are rounded up to an even count. Center targets describe theoretical taut-chain geometry; they do not include running slack, chain wear, or suspension movement. Confirm chain alignment, clearance, adjuster travel, and the required slack on the actual motorcycle before cutting or fitting. Matching pitch alone does not make different chain widths interchangeable.

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