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The Iron Age

There may be a fertile imagination behind every great idea, but behind every commercially successful idea is a great marketer. In the world of tractors, few marketers were better than Allis-Chalmers Tractor Division general manager Harry Merritt. 

It was Merritt, after all, who settled on the Persian Orange color that quickly became an Allis trademark.

Merritt didn’t just have good taste in colors, though. He also knew a good idea when he saw one – or heard about one. 

It so happened that his company’s new workhorse, the model U, needed a leg up on the competition.

When word of an IHC dealer in Iowa who installed truck tires on steel-wheeled Farmalls filtered back to Merritt, a eureka moment ensued. Merritt knew the time had come to put rubber under his steel-shod horsepower.

Merritt’s acquaintance with Harvey Firestone didn’t hurt in bringing his brainstorm to fruition. 

Firestone was intrigued with the possibilities and threw his resources into helping Allis-Chalmers’ engineers test the concept. Soon, a pair of 12×48-inch smooth airplane tires showed up at the Allis headquarters. 

Allis-Chalmers chief engineer C.E. Frudden found a ready test subject in a model U owned by Albert Schroeder. That’s how Schroeder’s farm – situated near Waukesha, Wisconsin, and close to Allis headquarters – became home in 1932 to the first evaluation site for pneumatic tractor tire performance.

The smooth tires quickly proved their worth by towing loaded trailers down the road. Yet in the field, they tended to spin out. It didn’t take long for Frudden and his staff to discover that the tires performed better if their inflation pressure was dropped – and not by a little bit.

Low pressure is the key

Eventually, inflation was lowered all the way down to 15 psi from an original 70 psi. Performance in the field, particularly plowing, improved greatly. A week of running the rubber-clad U convinced Schroeder that tires were the ticket. 

Of course, the Allis engineers were also finding that the tractive efficiency of the U was greatly enhanced with tires. So much so that the tractor developed over twice as much drawbar horsepower on rubber.

Putting rubber on tractor rims was not a new idea. Tractor historian R.B. Gray found that rubber, in the form of solid rubber cleats, was used on steam tractor engines as early as 1871. Again, at least one implement dealer was already performing truck tire conversions.

Economic advantage

The real breakthrough, however, due to Allis-Chalmers’ efforts, was the discovery that pneumatic tires enhanced performance. Certainly, they offered creature comfort to farmers, as well. To plow twice as many acres on the same amount of fuel made the concept an economic no-brainer.

To promote the concept, Merritt began holding field
demonstrations, pairing a U on steel against one on rubber.

To drive the point home, he had a fleet of U’s equipped with a high-speed fourth gear and raced them at tracks across the country. Famed race car drivers like Barney Oldfield, Frank Brisko, and Ab Jenkins performed in front of an estimated 1 million people during 1933 alone. In fact, Brisko set and still holds the top speed record for a tractor at 67.877 mph.

The rest is history. Steel wheels soon littered junkyards across the nation. Pneumatic tractor tires sold like hotcakes. Harry Merritt would be forever associated with one of the more profound advances in tractor technology.

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