Sprockets don’t start out as bad characters; they become that way. Over time, based on the environments they’re subjected to and the circles they run in sprockets can turn and wreak havoc on your bike’s performance and reliability. Taking a moment on a regular basis to visually check your machine’s chain wheels can tell you a lot about how they are likely to act today and in the future.

Are your sprockets upstanding performers, or are they a bit shady? To answer that, let’s do a little profiling.


The unstraight and narrow

When new, a sprocket is made to align perfectly with a matched drive chain to provide exact meshing of the chain’s links with the teeth of the front and rear sprockets. The result is smooth, efficient and reliable performance. Over time, as the sprocket teeth dig into the chain’s rollers thousands of times each minute under acceleration and deceleration, the chain begins to elongate and the profile of the sprocket teeth begins to change.

When viewed from the side, the profile of the good sprocket will reveal tall teeth that are thick, straight, and have blunted tips. The profile of a worn sprocket shows gear teeth that are no longer straight but are curled and have sharp, pointed tips. The sprocket teeth will also be worn shorter and narrower from constant rubbing with the chain. Ultimately, a sprocket can become so worn that the sprockets can no longer “grab” the chain and will allow the chain to skip over the sprocket teeth. Not good.

What makes good sprockets go bad?

Modern, quality chains and sprockets such as those from Sunstar® perform exceptionally well. Even so, over time, all chains and sprockets wear with use. How quickly they wear depends on how well they are maintained. Lack of lubrication is a major contributor to rapid driveline wear as dirt and grime work as abrasives, grinding away at the metal components. Misalignment of the sprockets will also accelerate chain and sprocket wear (make sure those wheel adjusters are even!). Certain sprocket materials are more prone to wear than others as well. Aluminum is lightweight but is softer and wears more rapidly than more durable steel sprockets.

The tooth and nothing but the tooth.

Continuing to ride with a worn, “stretched” chain causes the chain to ride up on the teeth of the sprocket, putting excessive force on the top portions of each tooth, resulting in severe and rapid wear of the sprocket. That’s why it’s so important to replace sprockets and chain as a set to assure proper, full-tooth engagement of the chain with the sprockets. It may cost a little more now but will save you money and worries in the long run.

When it comes to your bike’s sprockets, profiling is a good thing. Check the profile of your machine’s sprockets weekly. Then replace all questionable driveline components as a system with new, quality products.

Explore the wide range of performance sprockets at Need help selecting the right parts for your needs? Just ask!

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