1914 Thor motorcycle. Image courtesy Mecum Auctions.
We featured a story in the September issue of Hemmings Motor News about the 1914 Thor motorcycle sold in a recent auction. We did some added research into the company that built Thor motorcycles and were surprised to see some recognizable names associated with the business.
What do Indian’s Oscar Hedstrom, Crocker motorcycle’s Al Crocker and Harley-Davidson’s Bill Ottoway all have in common? All three worked with or for the Aurora Automatic Machine Company during the early days of American motorcycle manufacturing. What do Sears, Chicago, Reading Standard, Indian and Torpedo motorcycles all share in common? They all used an Aurora-built engine at some point during their manufacture.
The Aurora Automatic Machine Company was started in Aurora, Illinois, in the 1880s and manufactured cast steel components for many purposes, including bicycle parts. Bicycling was very popular during that era (and beyond the turn of the century), and the company prospered from its precision castings used on numerous bicycle models. Some of these manufactured parts ended up on bikes created by Oscar Hedstrom, who was building his own gas-powered engines based on the French De Dion design, for motorized bikes. These were used as pacers or dernys for competitive bicycle racing. These motorized bikes circled the track at breakneck speeds and the pedal bikes rode in their aerodynamic slipstream until they crossed the starting line at speeds of up to 75 MPH. Hedstrom’s engine design and the speeds it could achieve on the track got the attention of bicycle racer George Hendee. The two formed a business partnership that would become the Indian Motorcycle Company in 1901.
Indian’s plant in Springfield, Massachusetts, had no manufacturing facilities to reproduce Hedstrom’s designs, so they sent one of the engines to Aurora, Illinois, to see if they could produce and supply Indian with their engine castings. Machinists at the Aurora factory noticed the Hedstrom design overheated very quickly and improved the castings by adding additional cylinder wall strength and fins to the castings to improve air cooling. The changes were approved by the Indian factory and the two companies entered into a production agreement which made Aurora Automatic Machine Company the exclusive engine supplier for all Indians built from 1902-1907. Part of the production agreement allowed Aurora to sell these same engines to other motorcycle manufacturers, as long as Aurora was not in direct competition with Indian by building their own cycles, and royalties from sales of the engine to other companies were paid to Indian. Aurora quickly formed the Thor Motocycle and Bicycle Company in 1903, allowing Aurora to sell its engines to just about any other brand name being produced at that time including Sears, Torpedo, Chicago, Reading Standard and several others.
Aurora was also selling kit motorcycles that could be assembled by the consumer into a working motorcycle; however, these kit bikes did not violate the agreement with Indian. Once the Springfield Indian plant opened its own manufacturing facility for castings in 1906, and the engine manufacturing agreement was ended, Thor quickly began opening dealerships and selling complete motorcycles.
1909 Thor, on the lawn at Pebble Beach. Photo by Matt Litwin.
Thor upgraded the engines to feature automatic intake valves and options included the choice of a battery or magneto ignition as well as chain or belt drive. Thor riding performance was further improved in 1910, when a two-cylinder engine became available. These early v-twins looked odd by today’s standards, as the rear cylinder stood upright while the front cylinder sat down low to the frame, a design that left room for the ignition to be mounted behind the engine. In 1911, the company added a free-wheel engine clutch and belt-drive option was limited to only the single-cylinder engines. In 1912, the v-twin design became more standardized with push rods and thin, tin rocker arms added to the cylinder head, while the position of the cylinders was moved rearward, into a 50-degree “v” shape. Competitors in the business, like Harley-Davidson, Excelsior and Indian, marketed their motorcycles by winning races; it was the best kind of advertising the company could buy at that time, and an opportunity that Thor explored with several performance bikes designed by Bill Ottoway, the head of their racing department from 1908-‘12. After some early success in off-road and endurance racing, the other manufacturers soon surpassed the Thor factory bikes and the racing endeavor was abandoned. Bill Ottoway was later hired to build racing machines at Harley-Davidson and enjoyed many successes with H-D’s pre-war race teams.
One of Thor’s earliest engineers was Northwestern University graduate Al Crocker, who worked for the company during the week and raced Thor motorcycles in off-road competitions on the weekends. Crocker befriended fellow racer and Indian partner George Hendee, and Hendee eventually convinced Crocker to move from Aurora Automatic Machine Company to Indian. Al Crocker’s story is legendary; after working for Indian and running some of their dealership franchises, Al moved to California in the 1930s and started his own dealership, ultimately creating his own famous brand of Crocker V-Twin racing motorcycles.
The 1915 Thor motorcycles received magneto-powered headlamps and taillamps, and a three-speed transmission was added in 1916. By then, however, the company was losing market share to the other brands and began moving away from motorcycle manufacturing. They stopped producing engines by the end of 1916, and while they did produce later bikes, these were built from leftover inventory. By the late teens Thor motorcycles were no longer sold.
The company returned to their manufacturing business, subsequently producing Thor-branded pneumatic and power tools as well as appliances under the name Aurora Pneumatic Tools well into the fifties. Historian Greg Walters has written extensively on the history of the Thor Motorcycle Company and the Aurora Automatic Machine Company, and you can learn more here.
