The history of the car tire

The invention of the wheel dates from 3500 BC. The first steel band around the wheel was seen more than 1000 years BC. We take a look at how the tire on the automobile came into being and developed into the car tire as we know it today.

The wheel

Even before the invention of the tire, we first had the wheel. The earliest evidence of carts with wheels dates from the early Bronze Age, around 3500 BC. Excavations and other historical sources have established that the wheel was used almost simultaneously in Mesopotamia, the Caucasus and Central Europe. At that time the wheel was nothing more than a solid wooden disc, made of two riveted segments, with a hole in the middle for the axle (see illustration). The question of which of the three cultures actually invented the wheel remains unresolved to this day.

According to historians, it was the Egyptians who around 1500 BC were the first to use wooden spoked wheels instead of solid wheels. The wooden wheel with spokes was considerably lighter and larger in diameter. As a result, traveling on sandy roads (desert) and muddy paths became easier and more comfortable.

The steel band

A tire is the component that must support the weight of the vehicle, protects the wheel from damage and wear, and ensures better contact between the wheel and the road surface.

The first steel band around the wheel was seen on Celtic wagons around 1000 BC. The steel band made the wooden spoked wheel stronger and more wear resistant. Making a wooden wheel with a steel band was skilled craftwork. The hand forged steel band was first heated until red hot, then hammered around the wooden wheel and finally cooled with water. As it cools, the steel band shrinks and clamps the wooden wagon wheel into a strong whole (see image below).

Two fine examples of carriages with wooden spoked wheels fitted with steel rims are the Portuguese Traquitana horse carriage from 1775 and the farm wagon from 1884, both on display at the Louwman Museum. These wooden spoked wheels with metal rims were also used around the year 1900 on the first generation of automobiles that were derived from the horse carriage. The wooden wagon wheel with steel rim remained virtually unchanged until 1870, when wire spoked wheels and the rubber tire were invented.

The solid rubber tire

It was around 1600 BC that natural rubber (latex) was discovered. Latex is a sticky, milky sap that is tapped from the rubber tree. To make it suitable as rubber, the latex is vulcanized. In this process, sulfur is added to molten latex and the latex (the sap) changes into a smooth, flexible and elastic material, suitable for many applications. The use of latex as the basis for the solid rubber tire began in 1867. Robert Thomas received the patent that year, and production was carried out a year later by the North British Rubber Company. The 1886 Benz Motorwagen and the 1895 Benz 5-HP Phaeton in the Louwman Museum are two fine examples of vehicles with spoked wheels and solid rubber tires.

Synthetic rubbers were invented in the Bayer laboratories over the course of the 1920s. Synthetic rubber consists of various polymers made from petroleum and has characteristics comparable to polymers from natural rubber. Because of the scarcity and specific properties of natural rubber, tire manufacturers use both natural rubber and synthetic rubber, depending on the application of the tire. Today, synthetic rubber accounts for two thirds of total rubber production worldwide. Synthetic rubber, especially neoprene developed by DuPont, is, unlike natural rubber, more resistant to heat, oil, and gasoline. As a result, neoprene rubber was also used for fuel hoses, sealing rings, and insulation material.

The pneumatic rubber tire

In 1888 it was the British veterinarian John Boyd Dunlop (see photo) who is regarded as the inventor of the very first air filled tire.

The invention arose from the annoyance John felt when he saw his 10 year old son riding around over the cobblestones on his three wheeled bike with solid tires. Dunlops pneumatic tire was first used on the bicycle. John Dunlop experimented with a rubber tube that was glued to the rim and wrapped with a textile band. It was at the end of 1890 that production of the pneumatic bicycle tire began by Dunlop Pneumatic Tyre in Belfast. Dunlops production of the pneumatic car tire took place in 1900.

The very first pneumatic car tire, however, did not come from Dunlop but from the brothers Andre and Eduard Michelin in 1895. That year the air tire was used for the Paris-Bordeaux-Paris race and, despite the many punctures, attracted a great deal of interest. People were impressed by the comfort of the air tire. Michelin & Cie. improved the tire and before long they became the leading manufacturer of pneumatic car tires in Europe. At the same time, the solid car tire gradually disappeared from the market because of its poor comfort.

From the early 1900s, the pneumatic car tire consisted of an inner tube that holds the compressed air and an outer tire that protects the inner tube and provides traction (see image).

The outer tire A, fitted with multiple canvas layers, is the chamber in which the inner tube B is inflated to a pressure of 4 to 5 bar. When the inner tube is inflated, the beads of the outer tire lock into the steel rim C. By means of several bolts with wing nuts around the rim, the bead of the tire is clamped into the rim. This prevents the tire from shifting in the rim while driving. However, this screw bolt with wing nut did have disadvantages. It can cause difficulties when mounting an outer tire and may lead to damage to the inner tube. As a result, the use of a tire and rim fitted with these screw bolts with wing nuts was only short-lived. An example of this can be seen on the Spyker 60HP Racing Car of 1903 in the Louwman Museum.

White and black belts

In the early period of the pneumatic tire, the tire was usually made from carbon free rubber. The tire then had the white color of natural rubber (latex). By adding black carbon to the latex, the tire became stronger, more wear resistant, and more heat resistant. The lifespan of that first generation of black tires was about 4000 km. From a purely cosmetic point of view, black tires were also easier to keep looking good than the white natural rubber tires. The black tire soon came into general use. Remarkable in this context, however, is the use of white wall tires, which were popular in the 1920s and 1950s, especially on prestigious cars from the United States. An example of a car with completely white (latex) tires is theFord Model A from 1903which can also be viewed in the museum.

The diagonal and radial tire

It was in the 1920s that, due to the increasing use of cars and higher driving speeds on public roads, the characteristics of the tire were improved. The tire became wider and more flexible, and the rubber of the outer tire was reinforced with layers of textile embedded in the rubber. These tires are known as diagonal tires (Bias-Ply) because of the cord layers that are placed diagonally in relation to the direction of travel (see drawing). Diagonal tires are still being produced and sold to owners and collectors of antique cars from this period.

In 1946 Michelin introduced the radial tire for the first time. The tire gets its name radial tire because of the cord layers that are placed radially (at right angles) to the direction of travel. The radial tire is further reinforced by steel cord layers that run around the circumference of the tire (see drawing). After the death of Andre Citroen in 1935, Citroen was taken over by major shareholder Michelin, with Pierre-Jules Boulanger as vice president and head of the engineering and design department. It was therefore understandable that Citroen began using the Michelin radial tire on a large scale, such as on the Citroen 2CV that came on the market in 1948. Compared with the diagonal tire, the radial tire has a longer service life, better steering stability and lower rolling resistance, resulting in lower fuel consumption. However, the radial tire is somewhat stiffer and, due to its more complex construction, also about 40% more expensive.

The breakthrough of the radial tire

Because of the specific characteristics of the radial tire, the car did require a modified suspension. In general, it is not recommended to use radial tires on cars designed for bias ply tires. From 1950 onward, radial tires became the global standard. An exception to this was the American tire industry, which wanted to stick with the cheaper bias ply tire. In addition, the American automobile industry saw a threat in the costs of adapting the suspension for their new models. Most American car and tire manufacturers described the radial tire as 'a freak product that is not going anywhere'. They were not willing to make the public pay more for a stiffer tire, and so the industry continued to produce only bias ply tires. The only exception was B.F. Goodrich with the Silvertown Radial 900, introduced in 1965, but it was not a success.

The situation changed when the oil crisis broke out in 1973. In America, the gasoline price went from 30 cents to 1 dollar per gallon. The American market demanded more economical cars. In 10 years, automobile imports rose from 15 to 28 percent. All imported cars naturally had radial tires, and before long Michelin and Bridgestone were flourishing with their tires on the American market. Goodyear eventually produced a radial tire in 1977 after a multimillion investment. Other American tire companies started working together or were bought out. In 1983, all new American cars came with radial tires.

The tubeless tire

In 1955 there was an important change in tire construction. After a long period of testing and evaluating various patents, the tire without an inner tube, the tubeless tire, became the standard for new automobiles.

The traditional pneumatic tire with inner tube had a number of disadvantages, such as the difficulty of mounting the tire and inner tube, and the excessive heat that can arise from friction between the inner tube and the tire, which can result in a blowout.

The new tubeless tire was easy to mount and safer. The risk of a blowout was small because there was no inner tube and, in the event of a puncture, for example from a nail, the tire would lose air slowly and therefore safely. Instead of an inner tube, the outer tire now formed one sealed chamber together with the rim. To achieve an airtight construction, the tire was sealed at the rim bed, and the valve with its rubber seal was mounted on the rim. It was B. F. Goodrich who first brought a tubeless tire to market in 1955.

The band's profile

The tread of the tire was soon given a pattern in the early days. It was found that this provides better grip on wet and muddy road surfaces. The pattern channels water and mud into the grooves and discharges them sideways. In addition, the pattern provides a certain degree of cooling for the tire. In the early period of the pneumatic tire, the tread was sometimes fitted with text that would leave a print on muddy roads, such as 'NON SKID', as seen on the 1917 Pierce-Arrow Model 38 in the Louwman Museum. Nowadays, tires must comply with strict international safety standards regarding, among other things, maximum speed and maximum load. This information, along with the tire size and the required rim size, is encoded on the sidewall of the tire.

The future

It is remarkable that for road transport the wheel with the tire has already existed for more than 3000 years. What will the future bring us? Will we continue using the wheel on the road for a long time, or will we start moving through the air in our own means of transport? After all, there are already maglev trains and helicopters.

Alfred Koeten