In 1919, the average car owner spent about a month’s pay to buy a standard replacement passenger tire that would last 8,000 miles.
Today, most people earn enough in a few hours to buy a premium radial guaranteed to run 10 times longer.
During this 75-year span, the most revolutionary innovations in tire technology were made. Breakthroughs include cord innovations and tubeless, radial and belted tire constructions
While undergoing major changes of its own, Modern Tire Dealer and its predecessor publications have chronicled them all.
Historically, dealers and consumers were very slow to accept changes in tire design, especially those changes which radically redefined the fundamentals.
They first came in 1900 when cotton fabric was wound into cords to serve as the tire reinforcement material.
Previously, the fabric had been square-woven.
With this construction, a flexing tire would set the fibers against each other in a sawing action, creating friction and heat that wore out the fabric quickly and shortened the life of the tire.
Though the cord-ply construction eliminated this problem and tripled the average mileage for tires from 2,500 to 7,500 miles, it took nearly 20 years for car owners and even many tire dealers to accept this improvement. The cord-ply carcass is still used today, but the cord material used has been transformed from cotton to wire to rayon to steel to nylon to polyester to fiberglass to aramid and back to polyester.
The next technical innovation was development of a tire that required lower air pressure, thus improving ride comfort and handling.
This “balloon tire” suited the automotive engineers’ needs for a lower center of gravity.
This design made it possible to increase the tire section while reducing the rim diameter.
The result was a tire with bulging sidewalls and a wider footprint.
The balloon tire was conceived in 1920 and would eventually set the modern standard for tire sizing.
Nearly 30 years later, tire engineers finally reached a long-sought goal — creation of a tubeless pneumatic tire.
B. F. Goodrich was the first to successfully implement the basic idea.
It had been patented about 50 years earlier, but couldn’t be built because of limitations in rubber technology.
The tubeless design generated less heat than tube tires, increasing speed capability and lowering fuel consumption.
These tires were also safer.
Instead of a blow-out. a puncture would cause a “slow-out,” a more gradual release of air.
Tires — TBA Merchandising, a past incarnation of MTD, conducted a survey in 1955, eight years after the tubeless tire was introduced, to see if independent dealers and service stations approved of it.
They did not, and would not for a few more years.
In 1948, Michelin pioneered the radial tire, the most important advance in tire technology so far.
Laying the cord-plies radially (at a 90 degree angle) from bead to bead, rather than at a bias, increased tread wear, traction, tire strength and reduced rolling resistance.
U.S. tire manufacturers started marketing replacement radials in the mid-1960s. However, the first original equipment radial fitments on the 1967 model Ford Mustang and Cougar were Michelins.
Like the tubeless tire, the extreme design change of the radial initially scared away most dealers and consumers. Their apprehension was heightened by the radial’s under-inflated look compared to balloon tires.
Radials were finally accepted by the motoring public in the early 1970s and are currently the tire of choice for virtually all vehicle applications.
Belted tire construction was introduced in 1963 by the Armstrong Rubber Co., with belts made of cords adding durability when placed on top of the existing cord-plies.
Three years later, bias-belted tires featuring a polyester carcass and fiberglass belts became the industry standard Belts were soon added to radial tires. Today, most belts are made of steel cording.
The bulk of the 1970s was spent improving the handling and traction performance of radial tires.
Engineers worked to lower the tire profile — shortening the sidewalls — to improve the driving response.
Aspect ratios dropped from 78 to 70 on most standard passenger vehicles, while 60- and 50-series tires were available for high-powered sports cars.
Tread patterns were also changed dramatically during this time.
In 1977, Goodyear developed the all-season tire. These have a tread designed for both dry and wet traction and for winter and summer use.
The all-season concept caught on rather quickly because it eliminated the need to change-over from winter to summer tires every spring and fall.
Though all-season radials make up the majority of passenger tires sold in the U.S. today, they have not yet made substantial in-roads in the European or Asian markets.
The following decade marked the creation of the high performance tire market.
Aspect ratios were dropped even lower for application on vehicles ranging from the Chevrolet Corvette to the Honda NSX.
New compounds were formulated for better traction and lower rolling resistance.
Speed-ratings were developed to classify the performance a tire would deliver. They were more than a listing of speeds the tires could be driven without failing. They were also a measure of the tires handling, braking and safety on a scale that climbs from an S-speed-rating of 112 mph to a Z-speed-rating of more than 149 mph.
One industry executive predicted that “the modern high performance car would swallow up the luxury car of the 1960s and ‘70s.”
Though it hasn’t happened, the high performance niche has grown faster than any other automotive market segment.
In addition, a variety of directional and asymmetrical tread patterns have been designed to fit the needs of individual sports cars.
It appears that this customizing of tires for special applications is ushering in yet another era of tire technology.
At first, the 1990s appeared to be a period of niche product development with tires.
Goodyear was the first to achieve broad market success with an anti-hydroplaning concept tire that used a deep center groove, called an aquachannel, to disperse water from the tire’s footprint.
Goodyear’s Aquatred was preceded a year earlier by the Continental Aqua Contact which went after high performance customers.
While variations of this tire are abounding, the message is the same car owners want safety.
Following this message, manufacturers have been perfecting the run-flat tire — another goal that has existed since the introduction of the pneumatic tire in 1888.
Bridgestone, Goodyear and Michelin have all designed tires that will support the car at zero pressure.
Time will determine if this concept is marketable. Car manufacturers certainly hope so — it would eliminate the need for a safety spare, reducing space and weight limitations so that designers can build more fuel-efficient vehicles.
The future world of tire technology will inevitably focus on combining the attributes of performance, safety, mileage and value with as few compromises as possible.
Whether this will require another radical change in tire construction or simply a continuous stream of minor adjustments is anybody’s guess.
