Vroom! That’s the unmistakable sound of a Harley. Or the unmistakable sound of your Harley-Davidson stock going up.

Of course no one gave much thought to stock prices back in 1903 when William Harley and his boyhood friend Arthur Davidson and Arthur’s brother Walter teamed up to build a “power cycle,” which, as it turns out, couldn’t conquer even modest inclines without pedal assistance. Back to the drawing board.

By 1906 the bugs were worked out and Harley and the Davidson brothers were mass producing motorcycles. During World War I more than 20,000 Harley-Davidsons were provided to the military. By the 1920’s Harley-Davidson was the largest producer of motorcycles in the world. The company was one of two motorcycle manufacturers to survive the depression, doing so by manufacturing industrial power plants based on motorcycle engines. Harley-Davidson again produced motorcycles for the military during World War II, resuming its civilian production when the war ended.

Like all big companies, Harley-Davidson had its ups and downs. Its reputation was damaged by Hollywood’s production of outlaw biker gangs. In 1969 the company was bought by well-intentioned American Machinery and Foundry, which streamlined production and slashed the workforce. The quality of the bikes suffered and labor subsequently went on strike. The motorcycles rolling off the assembly line were clearly inferior. It was during this time that Harley-Davidson became known as Hardly Drivable. Another name, Hogly Ferguson, gave rise to the cycle’s nickname “Hog.”