Whether you are purchasing a chain for a motorcycle, car, chainsaw or bicycle, it is important to know how to measure the chain for replacement. If the existing chain is not measured correctly, the new one will not fit, leading to inoperable machinery or unreliable transportation. Chain sizing is measured with three separate measurements: pitch, gauge and length. Learn how to measure all three at home so you can get the chain you need and get back to work or back on the road.
Remove the chain from its machine. Many drive chains have a master-link that can be used to remove the chain easily. Otherwise, use a chain-breaker to remove a link to separate the two ends of the chain.
Measure the distance between any three consecutive rollers on the chain using both a standard and metric ruler. Divide this measurement by two. This is the pitch measurement of the chain. Write down both the standard and metric measurements so you can remember them.
Measure the thickness of one side of a single link in the chain. This measurement will be very small, so you will need a ruler with very small increments to measure reliably. Write this measurement down in both standard and metric. This is the gauge of the chain.
Count the number of links in the chain. Keep in mind that one link comprises a large connector and a small one. Recount to be certain you have the correct number of links, then write down this measurement. This is the chain's length.
Take your measurements to where you need to purchase your new chain. Make sure that the new chain matches your measurements as closely as possible.