Pleasant acceleration, short braking distances, and a smooth ride – this is what makes most people enjoy driving. But how does this overall positive driving experience come about? It helps to have a look at the physics, and that’s exactly what we’d like to do with you today!

Let’s start by going all the way back to the 17th century. It was already clear to Newton: with large masses, you need to apply a strong force to change the direction or speed. For motorists, this is already reason enough to choose alloy wheels.

Newton’s law: less mass, more driving pleasure

Newton defined his second law, which describes straight-line movement, in 1687. The simplified and now widely known formula is:

F = m x a

Here F stands for the required force, m for the mass, and a for the object’s acceleration. This may sound very theoretical, but you can notice it in many everyday traffic situations. For example, you must have already noticed how much slower your vehicle accelerates when it is fully loaded. Or how much longer the braking distance is when the trunk is full. So it’s clear: a heavy vehicle is sluggish – both when accelerating and braking.

The universal law: with full force

This correlation applies not only for objects in motion on a flat surface, but also for so-called flywheels. In vehicle construction, this category includes drive shafts, axles, and wheels. Here, the moment of inertia indicates how much force must be applied to change the rotational movement. What does this mean in practice? Quite simply: to reach a certain rotational speed, you have to give more gas.

Rotation: size makes the difference

The mass of a flywheel is not only important because of its weight. The distribution is also a decisive factor influencing the force that has to be applied. A flywheel whose mass is concentrated on the outer circumference quite far away from the axis of rotation will have a high moment of inertia. A strong application of force is required to change the rotation of the wheel. If we move the same mass closer to the axis of rotation, the wheel’s moment of inertia decreases and it becomes easier to change its rotational movement.

What does this mean if you’re looking for a suitable wheel? Larger wheels often look very stylish and sporty, but they directly affect the cars’ performance. When it comes to grip, wide wheels are best. The larger contact surface on the road improves steering and therefore boosts driving comfort.

If you want to calculate the moment of inertia and acceleration for your car, you can use the various calculators on this page. You can find further information on braking torque, flywheels, drive shafts, and more there.

Whether you choose large or small wheels is up to you. Beyond physics, it’s also naturally a matter of taste. Finding the right alloy wheel for your car is a breeze with the wheel configurator from RIAL.