In 1966, Huffman introduced a new long-wheelbase bicycle frame called the "Rail". The new frame was approximately 4" to 5" longer than previous models. The new frame became Huffman's base model until 1968. In 1968, in an effort to market a children's bicycle with an automotive theme, Huffman designers added a car-type steering wheel in place of handlebars to the "Rail" frame, which became the "Huffy Wheel". Tall "stick-shift" derailleur gear shift levers mounted on the frame top-tube imitated the gearshift levers of popular muscle cars of the day, while many banana-seat cycles were fitted with tall chromed "sissy bar" passenger backrests at the rear of the seat. In mid-1968, Huffman released the "Flaming Stack" chain guard, which was designed to look like the distinctive side exhaust pipe covers on the Corvette sports car. Later that same year, Huffman released a new "Slingshot" model with 16" front dragster wheel, and 20" rear. The new 1969 models where the last year for the three-bar Rail frame style. In 1970 Huffman deleted their three-bar frame and went to a two-bar Rail frame, eventually adding additional two-tone fade paint jobs along with Persons striped seats. These designs continued in production until 1971 when new safety and manufacturing restrictions from the BMA (Bicycle Manufacturers Association), the Consumer Product Safety Commission (CPSC) and other U.S. federal agencies forced the discontinuance of the "Wheel", the top-tube mounted "stick-shift", the "sissy bar", and many other stylized features of children's bicycle designs.