Tire Basics
A tire is a ring-shaped covering that fits around a wheel’s rim in order to protect it and yield better vehicle performance. For example, automobile and bicycle tires provide traction between the vehicle and the road as well as providing a shock absorbing, flexible cushion.
Early Tires
The first tires were simply metal bands wrapped around wooden wheels that greatly improved the durability and service life of the wheels. After the development of rubber, the metal bands were replaced with thick rings of solid, dense rubber.
Modern Tires
Eventually, solid rubber tires were replaced by pneumatic, inflatable tires, consisting of a doughnut shaped body of wires and cords encased in rubber and filled with compressed air to form an inflatable cushion.
Characteristics
Tread is the outermost part of the tire that comes in contact with the road surface and is composed of the following:
- Tread Lugs: These provide the contact surface in order to provide traction. When a tread lug contacts the road surface, it compresses and is deformed as the tire rotates. Tread lugs recover to their original shape after leaving the road surface.
- Tread Voids: The spaces between tread lugs are tread voids, which allow for the tread lugs to have space to flex and deform as well as help channel away water, mud, and snow.
- Sipes: These are narrow voids cut into tread lugs that improve the flexibility of the lug to deform as it contacts the road surface. Sipes help reduce shear stress in the lugs and thus reduce heat buildup. Overall, sipes make measurable improvements to tire performance in snowy and icy conditions.
- Tire Wear Bars: Also called wear indicators, wear bars are raised features located at the bottom of tread voids and indicate the maximum amount of tread wear before the tire should be taken out of service and replaced.
Next: Tire Variants