ALL ABOUT TRACTORS

By Paul Wallen

 By 1900, more than a million tractors were on American farms. They rode on steel lug wheels. A McCormick 10-20 with lug wheels on hard ground was about the bumpiest, most jarring ride that existed at that time. It was my first plowing job, in fifth grade.

Harvey Firestone was a fourth-generation farmer that decided to do something about that. He created the first pneumatic rubber tire for a tractor. The year was 1932 and all the testing for the new tire had been done on his home farm.

By 1935, 14 percent of all new tractors being shipped had rubber tires. Other companies like Firestone had built their tire factories around the new design.

At the same time Nebraska Test #223 showed without doubt that rubber tires were far more efficient than steel lug wheels. An Allis Chalmers WC was used in the test, and Allis then became the first manufacturer to ship new tractors on rubber tires.

Tractors on rubber had been proven more efficient through various tests. One was to measure distance traveled on rubber versus steel for a set time. One test showed that steel wheels would travel 52.8 yards in 36 seconds, and a tractor on rubber would move 70.4 yards in the same length of time. Another test indicated that a tractor on rubber would consume less fuel than one on steel.

Tests of longer duration showed less downtime with rubber-tired tractors. The intense vibration on steel wheels was much less on rubber, with a corresponding reduction in metal fatigue.

Drivers found they experienced less fatigue due to the smoother ride. It didn’t take farmers long to recognize these advantages. They started cutting down the steel

on their existing tractors and welding on rims for rubber tires. If they bought a new tractor they wanted it delivered on rubber.

By 1940 95 percent of new production tractors were fitted with rubber tires. By 1950 that number was 100 percent.

State and county road officials started complaining about the damage to roads from

steel lug tractors. (Author’s note: On the road in front of our farm a sign was posted “Vehicles With Lugs Prohibited.” This was by the late 1940s. Those signs were everywhere in rural communities).

Additional tests showed conclusively that less soil compaction occurred from rubber versus steel lug wheels.

In 1946, radial tires arrived on the market. They have less rolling resistance. It takes a lower effort for these tires to roll over the ground. There is less heat buildup and better fuel economy.

Another big advantage of radial tires is less soil compaction. (Proper inflation is critical, however). Flotation is better, and they can carry more load at a lower tire pressure.

One disadvantage of radial tires is poor transport handling. As the transporting vehicle speed increases, if the tire is overloaded or under-inflated, sidewalls tend to bulge. Damage or puncture can occur.

A choice facing buyers is radial versus bias tires. Radials tend to wear longer than bias. They tend to provide slower wear, less soil compaction, a smoother ride. Traction is superior to bias, and they are best on heavier equipment.

Bias tires tend to be simpler construction and lower priced. The sidewalls are stiffer than radials, so in situations where sidewalls are at risk for puncture, bias has an advantage. A good example of that is forestry work.

Car and truck tires are designed for use on paved surfaces, carrying variable loads. Tractor tires must do the same, but in addition they will be used in loose or firm soil, sometimes full of rocks, and on flat, rolling or steep terrain. They will be used in dust, dirt and exposure to endless foreign objects that are often below the surface and out of sight.

They must be designed to maintain traction in endless conditions of temperature, moisture and uneven terrain. Tread design must provide that traction in all kinds of soil conditions. They have to be able to carry massive weights such as the Big Bud 747 which weighs up to 130,000 pounds.

On top of everything else the tires must be designed to minimize soil compaction. In short, a tractor tire faces more challenges than almost any other application.

Paul Wallem was raised on an Illinois dairy farm. He spent 13 years with corporate IH in domestic and foreign assignments. He resigned to own and operate two IH dealerships. He is the author of THE BREAKUP of IH and SUCCESSES AND INDUSTRY FIRSTS of IH. See all his books on www:PaulWallem.com. Email your comments to pwallem@aol.com.