Tire anatomy Tires have been around since the mid-1800s, and the earliest tires were made of solid rubber. Radial tires have now pretty much replaced other varieties since their technological design offers better safety and handling, particularly at highway-driving speeds. They enable better steering and grip the road more solidly, particularly when cornering or driving on curvy roads. They also last much longer than the older styles. Although bias tires generally had a useful life expectancy of 20,000 miles or less, modern steel-belted radial tires, if properly inflated and maintained, may last for 100,000 miles or more.
All modern tires have a number of elements in common.
When selecting and purchasing tires, it's helpful to know a little about how they are made. The casing is the inner body or foundation, which allows the tire to keep its proper shape when inflated. The earliest belts were constructed of cords made from cotton. Stronger materials such as fiberglass, nylon and polyester were later substituted for bias tires. Today nearly all tires have belts made from steel.