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
Raleigh Chopper to a T-bar-style shifter. (The early 1969 'Tall frame' model already sported the T-bar style, albeit in black with the elliptical window within the shifter cover.) The frame was subtly revised, and the seat moved forward, to help prevent the front of the bicycle tipping up. A small rear rack was added. The handlebars were welded to the stem to stop children from inclining the "ape hanger" bars backward, thereby rendering the bicycle almost unsteerable. A drop-handlebar version, the Sprint, was also produced, this differed from the standard Mk 2, as it had a slightly taller frame. The Chopper Mk