In addition to designing passenger cars, Fred and Augie Duesenberg were involved in auto racing for more than a decade.

In 1921 Jimmy Murphy drove a Duesenberg racer to become the first American car to win the prestigious Grand Prix at Le Mans, France.

Fred and his younger brother, August "Augie" Samuel Düsenberg, were the youngest of the family's seven children (four boys and three girls).

The eldest son, Conrad, purchased a 200-acre (81-hectare) farm in Floyd County, Iowa, near Rockford, where the family finally settled.

After working at a garage in Des Moines, Iowa, Fred and Augie had a bicycle repair shop in Rockford, but the business went bankrupt in 1903.

A short time later the brothers established another shop in Garner, Iowa, but Fred left the business in 1903 to work for the Thomas B. Jeffery Company, a manufacturer of the Rambler bicycles and early automobiles in Kenosha, Wisconsin.

In addition to producing a two-cylinder model, the company introduced Fred's patented four-cylinder engine design.

[7] In 1913, the Duesenbergs relocated to Saint Paul, Minnesota, where they continued to develop racing cars and automobile and marine engines.

[3][9] As other automobile builders in the early twentieth century did, the Duesenbergs used the Indianapolis Motor Speedway to test and race their cars.

The first Duesenberg appearance at the Indianapolis 500 occurred in 1912, when their Mason Motor Company-owned racecar practiced for the race, but it had a mechanical failure and did not compete.

In 1914, Eddie Rickenbacker, a future World War I aviation ace, drove a Duesenberg-powered racecar to a tenth-place finish and US$1,400 in prize money.

[14] With the outbreak of World War I, efforts focused on wartime production and racing at the Indianapolis Motor Speedway went on a two-year hiatus.

The Loew-Victor Company also made an agreement to have the Duesenbergs produce automobile and airplane engines for military use for the American, British, Italian, and Russian governments during World War I.

The Duesenberg brothers moved to New York City in 1917 to supervise operations at a new manufacturing site in Elizabeth, New Jersey, that was constructed especially for building aviation and marine engines.

Beginning in May 1921 the Duesenberg company manufactured passenger cars with advanced racing-car features at its new factory in Indianapolis at the corner of Washington and Harding Streets.

[3][22] From 1926 until his death in 1932, Fred focused on designs for passenger cars, which included the X, S, and J models, and served as vice president of engineering at Duesenberg, a subsidiary of the Cord Corporation.

[3][20] In October 1926, E. L. Cord told the Indianapolis Star, "The purchase of the Duesenberg factory is the culmination of my plans to be able to offer the world an automobile of undisputed rank.

Naturally, the production of this type of automobile, which carries a warranty of fifteen years, will be limited and we are now taking orders...."[citation needed] Early in 1927 the test board of the American Automobile Association presented to Fred Duesenberg with a bronze tablet in recognition of the leading part he had played in the development of several fundamental improvements in automotive engineering.

[22] In June 1931, during a Society of Automotive Engineers meeting in West Virginia, Duesenberg "predicted that speeds of 100 miles per hour (160 km/h) on the highways would soon be common.

In 1921, Jimmy Murphy drove a Duesenberg racecar to become the first American car to win the prestigious Grand Prix at Le Mans, France.

The Duesenberg racecar driven by DePaolo was involved in an accident and completed only twenty laps, finishing thirty-third in a field of thirty-eight drivers.

[30] On July 2, 1932, while returning to Indianapolis from New York, Fred was driving a Duesenberg passenger car with a prototype, high-powered engine and lost control of it on a wet Lincoln Highway on Ligonier Mountain, about two miles west of Jennerstown, Pennsylvania.

[32] Sales of Duesenberg automobiles declined during the Great Depression due to dwindling numbers of buyers for luxury cars.

[33] Although Fred Duesenberg was a self-made man who lacked formal technical training, his engineering expertise influenced the development of the automobile.

He is credited with introducing the eight-cylinder car in the United States and four-wheel brakes, in addition to other mechanical innovations[22][11] that included overhead camshafts and four valves per cylinder.

[citation needed] He was also patentholder of his designs for a four-wheel hydraulic brake, an early automatic transmission, and a cooling system, among others.

[11] Although his innovations were found in Indianapolis-manufactured cars, including Stutz and Duesenberg models, they did not appear on autos made in Detroit until nearly seventy years later.