Quick Maintenance: Motorcycle Chain Slack

Chain slack is something so simple yet so important. The correct amount of chain slack enables the rear suspension on a motorcycle to perform at its peak.

The right chain slack setting for your motorcycle depends on the make and model, so don’t rely on the so-called “three finger method,” which is exactly what it sounds like. In other words, the chain slack is measured by putting three (or two, as pictured) fingers between the chain and the swingarm, but it’s not the most reliable method. 

To measure chain slack, take a measurement of the play in the chain above or beneath the swingarm using a chain slack tool or tape measure. The chain slack setting for your motorcycle is found in the owner’s manual, and it should tell you where to take the measurement.

Why Measuring Chain Slack Matters

Like any other basic motorcycle maintenance task, measuring chain slack exists for a reason and should be taken seriously. 

If your motorcycle has too much chain slack, it'll experience what’s called “chain slap,” where the chain makes contact with the swingarm. The chain might also jump off a sprocket when there’s too much slack, which of course is dangerous and could lead to a nasty motorcycle injury.

Too little chain slack reduces the lifespan of the drivetrain components, specifically the sprockets and of course the chain itself. There’s also the risk of the chain snapping if there’s not enough slack in it.

Ready to measure the slack on your motorcycle’s chain? Watch the video above to see how to measure chain slack using a Motion Pro Slacksetter tool.