Bicycle handlebar a steep U-shape from the base, so that the rider's hands rest above waist-level. This style of bicycle handlebar became very popular in the 1960s after the introduction of wheelie bikes such as the Schwinn "Sting-Ray", Raleigh Chopper, and other highly stylized youth bicycles that imitated the appearance of drag-racing or chopper motorcycles of the day. Legislation in the United States introduced during the 1970s limited the maximum height of manufacturer-installed handlebars to 16 inches above the lowest seat setting; European Union safety regulations use a similar limit of 400mm. The apehanger style remained common in the US through the
Chopper bicycle to make their own. Arguably, a bought 'chopper' is not a 'chopper' at all, because no chopping was done—only a commercial transaction. There are various cycling groups and clubs around the world that feature chopper bicycle riders, such as the Choppercabras, Chopaderos, DHC Den Haag Cruisin', Freakbike Militia, Cranksters, SCUL, and C.h.u.n.k. 666. Such groups encourage all chopper bicycle riders to join them on rides celebrating different events and holidays. Because the frame of a chopper bicycle and a chopper motorcycle can be strikingly similar, and of a high enough quality/durability, it is relatively common to have an empty space,