Motorcycles and Hot Rods were the perfect. Motorcyclists bought up surplus military bikes and removed all the unnecessary parts like windshields and saddlebags to minimise weight. Rear fenders were "bobbed" or shortened just enough to handle a passenger and keep the rain and mud coming off the rear, and sometimes removed the mirrors, or replaced them with tiny ones, such as the type used by dentists in their work.
This type of home customization led to the rise of the "bobber". Then in the 60s, motorcyclists found that a longer front end allowed the bike to run smoother at faster speeds. The degree of neck rake and length of front end was modified on these bikes with this in mind. The Girder and Springer front ends were the most popular forks for extending in this fashion, although this does make the bike harder to handle at slower speeds. Nevertheless, some choppers have extremely long forks; as one biker said, "You couldn't turn very good but you sure looked good doing it."
To build or chop a traditional chopper an unmodified factory bike is used (usually a rigid Harley Davidson) and everything unnecessary to either move or stop is stripped or chopped off. Then the engine and transmission are removed and the frame is cut up and welded back together to make it lower and lighter. Performance parts are added or modified to increase speed.