If you ride a sportbike, adventure bike, or even a naked bike, chances are you’ve thought about fitting mods to further improve the performance of your motorcycle. Sure, changing your exhaust, fitting new tires, or maybe even opting for a reflash are things you’ve probably considered doing. However, there’s another effective, oftentimes overlooked way of optimizing performance: changing sprocket size.
Motorcyclists change the size of their sprockets to modify the bike’s performance characteristics, particularly in terms of acceleration, top speed, and fuel efficiency. The sprockets are an essential part of a motorcycle’s drivetrain, connecting the engine to the wheels via the chain. Nearly all chain driven motorcycles have two sprockets – the front sprocket (attached to the engine’s output shaft) and the rear sprocket (attached to the wheel’s hub). By altering the number of teeth on these sprockets – specifically the rear, motorcyclists can achieve different outcomes. Let’s gloss over what to expect if you decide to change the size of your rear sprocket.
Upsizing – Pros and cons
Fitting a larger rear sprocket on a motorcycle enhances acceleration and low-end power while decreasing top speed. The added torque to the rear wheel allows the bike to accelerate swiftly from a standstill or at lower speeds. However, this modification also increases engine RPM at a given speed, potentially reducing fuel efficiency and causing higher engine stress during cruising. It’s important to be aware of the trade-offs, including decreased top speed, more frequent gear shifting due to closer gear ratios, and possible increased wear on drivetrain components. Additionally, riders should consider that using a larger sprocket might lead to speedometer and odometer inaccuracies, depending on the motorcycle model, and consulting with experts is advised before making the change.
Downsizing – Pros and Cons
Fitting a smaller rear sprocket on a motorcycle increases top speed and high-end power, making it ideal for highway cruising and straight-line performance. However, this modification typically reduces acceleration and low-end torque, resulting in slower starts and performance at lower speeds. On the positive side, the lower engine RPM at a given speed can improve fuel efficiency during highway riding due to the longer final gear ratio. Similar to upsizing the rear sprocket, riders should be aware of potential inaccuracies in the speedometer and odometer readings and consult with experts before making the change. Considering these factors will help ensure a successful sprocket modification that aligns with the rider’s preferences and needs.
Things to look out for
When replacing your rear sprocket, several important factors should be considered. First, ensure that the new parts are compatible with your motorcycle’s make and model. Avoid purchasing cheap sprockets online and instead opt for reputable brands with positive reviews. Also, verify that the new sprocket matches your current chain setup, such as the type (e.g., 520 or 525 chains).
It’s a wise decision to replace not only the rear sprocket but also the chain and front sprocket simultaneously. This ensures that all components wear evenly and function optimally together. Whether you are increasing or decreasing the size of the rear sprocket, you may need to adjust the chain length by adding or removing links accordingly. Paying attention to these considerations will help ensure a successful sprocket replacement and maintain your motorcycle’s performance and safety.