Pierce-Arrow Model R

The Pierce-Arrow Model R is a truck model manufactured by the American firm Pierce-Arrow Motor Car Company from 1911 to 1922. Unusually for the period in America, it featured a worm final drive axle.
The Pierce-Arrow Model R was used in very large numbers by the militaries of the British Empire, France and Imperial Russia during the First World War, 11,350 being delivered to the three powers during the war.

Design

The Model R was a cab behind engine, rear-wheel drive truck with a payload capacity of. The Model R was available in two chassis lengths, the standard chassis had a wheelbase of and an overall chassis length of, the long chassis had a wheelbase of and an overall chassis length of. The bare chassis was in width.
The Model R was powered by a 4-cylinder inline T-head petrol engine, dual ignition was introduced with later models, a fuel tank was standard. The truck was driven through a three-speed transmission and the rear axle featured worm final drive, which was unusual for American trucks of that weight class at the time. It was fitted with a foot actuated transmission brake and hand actuated rear drum brakes.

History

In 1910 Pierce-Arrow was looking to expand their commercial truck business, and on the advice of a young engineer, Francis W. Davis, the company hired two designers from British truck manufacturers. Upon their arrival H. Kerr Thomas formerly of Hallford and John Younger formerly of Dennis, commenced designing a completely new range of trucks with payload capacities of. The first Model R was completed in May 1911. Between May 1911 and August 1914, Pierce-Arrow had built approximately 800 Model Rs, their advertised price in 1914 was.
During the First World War, large numbers of Model Rs were purchased by the militaries of the British Empire, France and Imperial Russia, and by the time of the Armistice in 1918, 11,350 Model Rs had been delivered. In British military service the Model R had a rated payload capacity of and was fitted with a variety of body types. 1,705 Model Rs were in British military service by 1918. The Model R also formed the basis of two British armoured fighting vehicles, the Pierce-Arrow armoured lorry and Pierce-Arrow armoured AA lorry.
Production of the Model R continued through the 1920s with progressive improvements, despite being quite antiquated by that time it had a better reputation than newer Pierce-Arrow models. Production of the Model R finally ceased in 1929, and in 1932 Pierce-Arrow ceased truck production altogether.
Model Rs were still in service with the French Army in 1940, serving during the Battle of France.