Tires - their composition and history

May 19, 2023

A tire is the point of contact between a vehicle and the road surface. It functions to provide traction for acceleration and braking, and to limit the transmission of road vibrations to the vehicle body. Inner tubes in tires were standard until the 1950s, when seals were developed between the tire and the wheel, leading to tubeless tires, which are now used almost universally.

The tread design of the tires is tailored to the characteristics of the surface on which the vehicle must operate. The deep design provides gripping action in loose soil and snow, while the smooth surfaces provide maximum contact for occasions such as racing.

Tire casing

Typical tire casings are made of layers of rubber compounds of varying proportions, reinforced with synthetic and carbon fibers or steel wire. The composition of the reinforcement and its angle of installation on the tread axis affect the tire's ability to respond to lateral forces generated during cornering. They also affect vibration transmission characteristics.

By 1990, longitudinal and radial ply constructions were being used, with two, four or more plies, depending on the design load capacity. An additional factor related to the load capacity of a particular construction is the pressure to which the tire is inflated. Newer designs also have a lower aspect ratio to increase the contact patch with the road to maintain a lower tire and, consequently, vehicle height.

Tire history

The first practical pneumatic tire was invented in 1888 by John Boyd Dunlop, a Belfast, Scotland-born owner of one of Ireland's most successful veterinary practices. It was an attempt to relieve headaches for his 10-year-old son, John. His doctor, John, later Sir John Fagan, prescribed a bicycle as an exercise for the boy.

Later, John Boyd Dunlop and Harvey Du Cross worked together to overcome significant challenges. They employed inventor Charles Kingston Welch and also acquired other rights and patents that allowed them to somewhat secure their pneumatic tire business. The pneumatic tire would become Dunlop Rubber and Dunlop Tires. The development of this technology relied on a number of engineering advances, including the vulcanization of natural rubber using sulfur.

Synthetic rubbers were invented in Bayer laboratories in the 1920s.

In 1946, Michelin developed a method of constructing radial tires. Michelin had purchased the bankrupt automobile company Citroën in 1934, so it was able to immediately adapt this new technology. Due to its advantages in handling and fuel economy, the technology quickly spread throughout Europe and Asia. In the United States, the outdated bias tire construction continued until the Ford Motor Company adopted radial tires in the early 1970s.