The 'Bobber' movement grew out of the American predeliction for chucking heavy stock mudguards into the weeds in the search for lighter weight and livelier performance, and 'bobbed' motorcycles (so-called for their truncate tails) first appeared in the late 1920s. They make an interesting contrast to hotted-up road/racers in the rest of the world, which generally included full, if narrow, mudguarding; the Bobber aesthetic grew directly out of Dirt Track racing in the States, as there was virtually no paved-road racing domestically pre-war, and the requirements are quite different from the European Grand Prix scene. And, typically, the fast crowd wanted to be seen riding what their track icons rode...the rules applied then as now, and since Indian and Harley didn't sell Dirt Track Replicas, the lads made them at home.
The Bobber evolved post-war into the Chopper, which flowered in the 1960s, but had it's own origins as far back as the late 1940s... which will be discussed Later; Who invented the Chopper?
(photo copyright The Vintagent)
(photo copyright The Vintagent)