Introduction to Choppers and Bobbers

A chopper is a radically customized motorcycle, archetypal examples of which are the customized Harley-Davidson Panhead V-twins seen in the 1969 film Easy Rider.

History

In the post-World War II United States, servicemen returning home from the war started removing all parts deemed too big, heavy, ugly or not absolutely essential to the basic function of the motorcycle, such as fenders, turn indicators, and even front brakes. The large, spring-suspended saddles were also removed in order to sit as low as possible on the motorcycle's frame. These machines were lightened to improve performance for dirt-track racing and mud racing.
Forward-mounted foot pegs replaced the standard large 'floorboard' foot rests. Also, the standard larger front tire, headlight and fuel tank were replaced with much smaller ones.Many choppers were painted preferably all in either flat black or in shiny metallic "metal flake" colors. Also common were many chromed parts (either one-off fabricated replacements or manually chromed stock parts). According to the taste and purse of the owner, "chop shops" would build high handle bars, or later "Big Daddy" Roth Wild Child's designed stretched, narrowed, and raked front forks. Shops also custom built exhaust pipes and many of the "after market kits" followed in the late 1960s into the 1970s. Laws required (and in many locales still do) a retention fixture for the passenger, so vertical backrests called sissy bars were a popular installation, often sticking up higher than the rider's head.
While the decreased weight and lower seat position improved handling and performance, the main reason to build such a chopper was to show off and provoke others by riding a machine that was stripped and almost nude compared to the softer-styled stock Harley-Davidsons, let alone the oversized automobiles of that time.

Traditional choppers

In the United States servicemen returning from World War II were looking for a thrill. Many veterans had been trained to work on automobiles and motorcycles and were looking to add a little excitement to their post-war lives with their newly acquired mechanical skills. Motorcycles and Hot Rods were the perfect hobby for them. 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 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.

Today's choppers

Choppers have enjoyed a large following. Companies like Jesse G. James' West Coast Choppers have been successful in producing expensive traditional chopper-style bikes and a wide range of chopper-themed brands of merchandise such as clothing and automobile accessories.
A distinction should be noted between true chopper (or chopper-style) motorcycles, and custom motorcycles, or 'custom cruisers'. Despite the name, a large percentage of the motorcycles produced by popular companies such as Orange County Choppers, Indian Larry, Falcon Motorcycles, Warlock Motorcycles, and Von Dutch Kustom Cycles are better described as 'custom' bikes rather than choppers. A distinction should also be made between choppers and bobbers. While both tried to improve performance by removing any part that did not make the motorcycle perform better, they differed in an important way: bobbers kept the original factory frame, while choppers have a modified form of the factory frame. When individuals were stripping their stock motorcycles and bobbing their fenders, the term "bobber" was born. When individuals started cutting (or chopping) and welding their frames thereby repositioning/restyling them, the term "chopper" was born. Chopping was the next phase in the evolution that followed dirt track bobbing.
While people assume that the chopper style motorcycles were built purely for aesthetics, there is a real performance advantage to the raked front end on these choppers. These motorcycles have a much more stable feel at high speeds and in a straight line than motorcycles with original factory front suspensions. However, like any other modification, there is a downside: the raked front end feels heavier and less responsive at slow speeds or in curves and turns. This is due to the longer trail measurement associated with increased rake.
Despite the personalized nature of choppers, and the wide availability of alternative designs, chopper builders have overwhelmingly chosen fat rear tires, a rigid-looking frame (even for a softail), and an original or replica air-cooled, pushrod v-twin engine. In the UK, due to the cost and lack of availability of the v-twin engine, many chose to use British engines from bikes such as Triumph or BSA; lately as availability has increased, Japanese engines have seen more use. Some people feel that the variety of engines and other components used more recently (especially on bikes built outside of the US) is diluting the signature appearance of the chopper style. Modern bobber builders tend to distinguish themselves from chopper builders with bikes styled before the chopper era. Today's custom choppers are usually seen as center pieces at bike night events around the world.
The United States of America, where most custom choppers reside, is one of the few countries in the world that allow custom-built choppers to be licensed for highway use. Many of these types of choppers are regarded as dangerous to operate and don't follow basic design geometry and lack many safety features in their construction.
Finally, an often overlooked style of chopper is the chopper bicycle. Inspired by the smooth, low lines of chopper motorcycles, today's custom chopper bicycle designer builds bicycles that pay tribute to the motorcycles they resemble.