United States Patent No. 5,023,958 (the ‘958’ patent) issued on June 18, 1991 for an aerodynamic bicycle helmet and expired last month on June 18, 2008.

A bicycle helmet protects a cyclist’s head by providing impact and shock absorption. Bicycle helmets have evolved from simple cloth or leather head coverings to hard outer shells supported on a network of straps or webbing. Bicycle helmets initially were unattractive to cyclists because they were poorly ventilated, cumbersome, and impaired performance. Turbulent airflow tended to develop at the rear of the helmets causing increased drag and vibrations. These vibrations, also known as buffeting, tended to dislodge and push the helmet in a forward direction on the cyclist’s head.

The bicycle helmet disclosed in the ‘958′ patent fixed the drag and buffeting problems by having an improved aerodynamic shape. The ‘958′ patent teaches a helmet design with a teardrop shape and three ridges or ripples molded in the surface centered on the top front of the helmet. The ridges lift and separate the airflow over the helmet thereby preventing the onset of turbulence at the rear of the helmet. The lack of turbulence improves aerodynamic efficiency and minimizes buffeting.

The teardrop shape helmet has become very popular amongst professional and amateur racing cyclists. Look for variations of the teardrop-shaped bicycle helmet at the upcoming 2008 Summer Olympic Games.

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