Thomas had been manufacturing a De Dion-Bouton tricycle since 1898. An early model of the Auto-Bi was created in 1900, and public availability began in 1901. On September 17, 1901, a Thomas Auto-Bi was mentioned in a Japanese newspaper article and went on sale 11 days later, advertised in the same newspaper.
By 1903, the company was the largest manufacturer of single-cylinder, air-cooled engines. The 1904 Auto-Bi had a 2.5-horsepower four-stroke 442 cc single-cylinder engine, a belt-driven transmission, and could reach speeds of 35 mph (59 km/h). The Thomas Auto-Bi was later joined by the Auto-Tri, a three-wheeled motorcycle, and the Auto-Two Tri, a motorcycle that could hold three riders.
In 1905, Thomas’ motorcycle business was spun off as The Thomas Auto-Bi Company of Buffalo. The company credited Clarence Becker for having invented the Auto-Bi. The same year, one of the company directors, William C. Chadeayne, established a new record for a transcontinental crossing of the United States in 48 days. By 1912, the demand for motorcycles had dropped significantly, and the Thomas Motor company discontinued all production of two-wheeled machines.
The Auto-Bi was in all respects a standard bicycle with 28* inch wheels. It used a 200 cc capacity engine which produced 2.25 hp. This was an air-cooled, four-stroke cycle, with automatic intake valve, an engine weight of 11.3 kg (25 lb), and body weight of 41 kg (90 lb).