Get into Gear: The Role of the Rear Sprocket
Apart from its obvious role as a vital part of the drivetrain, the rear sprocket is also a key visual feature of the back wheel. Rear sprockets are available in a range of striking finishes and colours. Don’t worry, though; it’s not a case of all show and no go.
Rear sprockets are available to buy in three types of material. These are hardened steel, aluminium and a combination of the two, known as interlink sprockets.
Hardened Steel: This material is the most common for rear sprockets. As with the much smaller front, rear hardened steel sprockets have slight variations in composition and hardening techniques.
These differences, especially in higher-grade steel, equate to a longer sprocket life, which reflects in their price point. In addition, the rear sprocket differs because they aren’t ever left ‘blank.’ In other words, all rear sprockets undergo heavy machining to create a uniform pattern around the inner sprocket circumference.
Manufacturers create these patterns primarily to save weight as extra weight adds resistance, meaning the engine must work harder to turn the wheel. In the real world, the resulting weight and resistance savings from this machining may be minimal but with races won by fractions of a second, every little helps.
Aluminium Sprockets: This type of rear sprocket is quite rare but is available in the 24MX line-up. These sprockets represent the ultimate in weight saving.
Aluminium rear sprockets, even though made from aircraft-grade aluminium, wear out faster than hardened steel. With steel being up to 200% denser than aluminium, the weight savings are apparent. What’s more, for competitive riders, high-performance components are essential.
Combination Sprockets: These sprockets, also called interlink or twin-ring, consist of a hardened steel outer sprocket combined with an aluminium inner ring.
This combination offers the best of both worlds, giving up to three times the lifespan of an all aluminium sprocket. The combo’s lightweight inner ring also means in size for size comparison, you can realise a weight saving of around 70% compared to its steel equivalent.
