Early tractors were massive and expensive. Their steel lug wheels gave poor traction and a rough ride. Lugs were prohibited on many roads. 1926 Hoyle Pounds modified a Fordson tractor with zero pressure truck tires on special rims to improve performance on sandy soils in Winter Garden, FL.
A successful business resulted. In 1929 Hessel Roorda equipped Farmall tractors with low pressure rubber tires to pick corn in muddy fields near Rock Valley, IA. Farmers found they performed well in all conditions.
In 1932 Allis-Chalmers, urged by Harry Merritt, tractor division manager, supplied a Wisconsin farmer with a model u tractor with firestone aircraft rubber tires at low pressure. This system operated unmodified for 8 years.
Farm magazine ads in 1934 quoted several university reports of as much as 1/3 less fuel and 1/4 more work with low pressure rubber tires compared to steel lugs. No new tractors in 1930 had rubber tires. By 1940, most did.