Which of the three primary drivetrains—chain, belt, or shaft drive—is better, is one of the most often asked issues in the motorcycle world. There is a reason why bikes have different types of drivetrains; it is obvious that all motorcycles on the market have undergone significant R&D from the manufacturers.
While hefty and durable shaft drive systems are frequently seen in heavyweight tourers, the reliable chain drive appears to be the preference for street and off-road vehicles. Conversely, belt drives are typically preferred by scooters and cruisers. What’s the reason for all this? Well, we'll find out today.
Chains are perhaps the most ubiquitous drivetrain of choice for sportbikes, dirt bikes, and certain cruisers and touring motorcycles. With only about 3% of the power lost during transmission, a chain drive is the most effective means to send power from the engine to the back wheel. They are robust, which makes them suitable for drag racing, and durable, which makes them the only ones used nearly entirely for bikes designed for off-road use.
Chains' major drawback is how much upkeep they require. The chain has to be cleaned and lubricated often. The cost and work required increase when the chain has to be replaced along with the sprockets. As opposed to a belt or shaft, a chain drive is not as silent or smooth. Additionally, you must carefully align the rear wheel so that the chain enters and exits the rear sprocket in a straight line. Not doing so can cause drastic premature wear and tear, and even negatively impact your motorcycle's performance.
Shaft drive is undeniably the best low-maintenance drivetrain. Its fluid just has to be periodically changed as regular maintenance. Since nothing needs to be aligned after everything is bolted up, wheel alignment is not even an issue. A shaft drive is durable and will endure the whole life of the motorbike, barring catastrophic failure. Due to these characteristics, several cruisers and touring motorcycles also favor it.
All things considered, shaft drives aren’t without fault. A significant portion of the power that is intended to get to your back wheel is wasted along the way since it must pass through so many moving parts. Torque rise is another drawback of shaft drives, especially for sportier riders. The rear of the bike lifts under severe acceleration rather than hunkering down, or squatting, as you might anticipate due to the force of the driveshaft rotating the back wheel. As a result, you are unable to benefit from the increased rear traction provided by the weight transfer as a belt or chain drive would otherwise provide.
Belts function quite similarly to a chain. They are most frequently seen in cruisers since they are smooth, minimal maintenance, and require no lubrication. Belts may last for around 25,000 to 30,000 kilometers if used properly, or even longer with more costly carbon and kevlar belts. In contrast, you need to lubricate your chain every few hundred miles or kilometers, whereas a belt needs no other maintenance other than occasional tension checks. They do, however, lose power at a rate of around 11%, which is a lot more than a chain, but still not as bad as a shaft.
Belts last longer than chains, although they are more susceptible to damage. For example, a belt can wear through and break from a stone lodged in a sprocket, but a chain will never experience this problem. Additionally, broken chain may be temporarily repaired on the side of the road to bring you home, but that's not going to happen with a belt, as belts are usually a single-piece construction. Although a replacement belt costs more than a chain, you can typically reuse your existing sprockets, which reduces the overall maintenance cost in the long run.