How to Check for Bike Chain Wear on Your GSD

As with all bicycles, some of your GSD’s parts are consumable. The chain is likely one of the first parts you’ll need to replace. But how do you know when it’s time for a new chain?

In this article, we’ll explain what chain wear (sometimes called chain stretch) is and how to check for it.

What is chain wear, and why is it a problem?

You may have heard chain wear referred to as chain stretch. While the chain does get longer over time, the metal doesn't actually stretch out. So what is chain wear?

Your bicycle chain is a series of interlinked plates, pins, and rollers. The distance between the roller centers (called the chain’s “pitch”) should be 12.7 mm (½”). This standard 12.7 mm pitch allows the sprocket teeth on the chainring and rear cassette to fit inside the chain correctly.

Each time you ride your bike, you wear away a tiny bit of the material that makes up the rollers and pins. Over an extended period, this can significantly decrease the overall size of the rollers, which effectively increases the chain’s pitch.

Increased chain pitch is a problem because it prevents the sprocket teeth from fitting snugly into the space between the rollers. This changes the amount and direction of the force applied to the sprockets by the chain, which can damage your entire drivetrain.

The chain is the least expensive part of your drivetrain to replace, so it pays to swap out your chain at the first sign of wear. A worn chain can also cause sloppy shifting, making your ride less enjoyable and potentially less safe.

How do I tell whether it’s time to replace the chain?

The easiest way to check for chain wear is to use a chain checker tool. These inexpensive tools let you check for chain wear in a matter of seconds. It’s a good idea to buy one and keep it with your other bicycle tools. We recommend storing it with your tire pump and dropping it into the chain to check for wear whenever you pump your tires.

If you’re not sure whether your chain should be replaced, you can always visit your Tern dealer for help.

How long should my GSD’s chain last?

How long your chain lasts before needing to be replaced depends on many factors, including your riding style, typical cargo weight, e-assist level used, and so forth.

In general, e-bike chains wear out a little bit more quickly than conventional bike chains. That’s because the motor system applies greater sustained power to the chain than a rider could alone. To mitigate this problem, we’ve outfitted the GSD with an extra-durable chain specially designed for e-bikes. With normal use, you can expect this chain to last a few thousand kilometers before showing signs of wear.