Ruan Bubear:

Your car’s tyres have an awfully important job to do. Yes, these ring-shaped pieces of rubber do more than simply deliver the requisite traction to keep your vehicle facing the right way on the tarmac.
 They also protect your shiny new alloy wheels and, far more importantly, support the substantial weight of the entire car and its contents. Without air-filled tyres, effective basic driving actions such as accelerating, braking and steering would be pretty much impossible.