Last Update: 23 February 2023
Part of keeping your motorcycle travelling smoothly and on the road has to do with the components which make up its “sprung and unsprung” weight. It’s also known as unsprung and sprung “mass” – the opposite of which is a motorcycle’s “sprung” mass.
Unsprung Weight is A Collection of Components
To speak of unsprung weight, this includes the collection of motorcycle components such as your rims, wheel axles, brakes / callipers, tires, and a portion of the weight and suspension links. Unsprung weight is largely a function of the design of a vehicle’s suspension and the materials used in the construction of suspension components.
This combined mass is one of the most critical factors affecting your motorcycle’s road holding ability. As unsprung weight is that portion of your motorcycle not supported by the suspension it is the most susceptible to road shock and cornering forces.
To make your steering and handling performance easier, it’s as simple as reducing unsprung weight. One way is to exchange your steel rims for lightweight – but pricey – aluminium, or state of the art, carbon fibre rims. These will allow you more precise steering inputs and improved “turning in” characteristics—plus look incredibly sexy on your bike!
The whole idea for better handling is to reduce unsprung weight.
Simple weight reduction by way of wheels is a key concept that many riders overlook. But you probably noticed more and more, that today’s motorcycle models are arriving from the factory with lighter weight wheels. Ducati is a good example of this using the famed Italian brand Marchesini for most sport and super-bike models.
Effortless Improved Handling
So here’s what really happens to the unsprung mass. When you ride over bumps and surface imperfections in the road, these cause tire compression(s), which induces a force on the unsprung weight. Every time you hit a bump, the wheel assembly is accelerated upwards, decelerates to a stop, and then accelerates downward until it reaches equilibrium. If the wheel can’t accelerate fast enough, shock is transmitted to the body, which may upset the balance of the bike.
The Whole Idea for Better Handling is To Reduce Unsprung Weight
The whole idea for better handling is to reduce unsprung weight because you’ll minimise the load placed on controlling the motion of the wheels and tires. This means that suspension springs, and shock absorbers will have a greater reserve capacity to control body motion; just as they were intended to!
The result is effortless better handling. Plus there’s a lower rotational inertia resulting in a quicker and more responsive steering, meaning less rider fatigue.
Adjusting your unsprung and sprung weight is a definite “must do” on your motorcycle customising list.