The Ford Model TT One-Ton Truck was good for only 15 mph, but that was good enough to put a nation of merchants and shopkeepers on wheels.

From the moment it was introduced in October of 1908, the legendary Model T Ford was put to use as a commercial vehicle, though it wasn’t really engineered for the purpose and its load capacity was limited. Recognizing the market demand, in 1917 Ford brougt out a real truck version of the Model T. Marketed as the Model T One-Ton Truck for its rated capacity of one short ton, it was commonly known as the Model TT.

The TT’s four-cylinder, 22 hp engine and two-speed planetary transmission were identical to the passenger car’s, as were the radiator, hood, and front fenders. But the frame and transverse-leaf suspension were heavier and the wheelbase was extended from 100 to 125 inches. A variety of larger wheels and tires were fitted over the years, initially with solid rubber tires at the rear.

The first 12,000 or so were delivered to the U.S. military for World War I, reportedly. From there, sales were opened to the public at an opening price of $600 not including bodywork, which could be provided by countless manufacturers and local shops in any configuration desired.

The key element that transformed the modest Model T into a real work truck was its  worm-drive axle, above, which replaced the standard bevel-gear differential and doubled the final drive ratio from 3.63:1 to 7.25:1. Obviously, this doubled the torque available at the rear wheels, but at a cost. While a Model T passenger car was capable of 40 to 42 mph, more or less, the TT truck topped out at not quite 20 mph. However, Ford Motor Co. recommended a maximum of 15 mph.

No matter, as the TT was still faster than a horse and wagon, and cheaper and easier to operate, too. Like its Model T sibling, the TT could be serviced by most any garage, or even by a home mechanic with limited skills. Ford eventually dropped the price to $325 ($50 more for electric starting) and offered several factory body styles, including a closed cab in 1925. Now thousands of merchants, trades people, and shopkeepers could afford their own trucks. Ford offered a Weekly Purchase Plan with payments as low as five dollars. In a 1923 ad the company boasted, “More than half of all trucks  now in service are Fords.”

Third-party upfitters supplied every kind of body for the Ford One Ton, from hucksters and panel wagons to dump trucks, even a Blue Bird school bus, while Warford, Jumbo,  and others offered auxiliary overdrive transmissions to address the speed issue. More than 1.5 million Model TT trucks were produced between 1917 and 1927, and they helped to put American business on wheels.