AeroTaper Bicycle Spoke Minimizes Wheel Drag in Crosswinds

Null Winds Technology (www.nullwinds.com) announces the AeroTaper aerodynamic spoke, providing reduced wheel drag in crosswinds.  First shown at the Interbike Bicycle Exposition in September 2014, this innovative spoke design tapers in streamlined shape from a thin bladed cross-sectional profile located nearest the wheel rim, to a more round cross-sectional profile located toward the wheel hub.  The patent pending aerodynamic profile minimizes wheel drag from spokes positioned in the critical drag-inducing region of the upper wheel assembly, where vehicle wheel drag is most highly concentrated.

The AeroTaper profile optimally reduces drag, both from headwinds impinging the upper spoke surfaces located near the upper wheel rim, and from crosswinds impinging spoke surfaces located lower in elevation toward the wheel hub.  This tapered spoke provides superior performance over previous full-bladed spokes, which suffer increased drag from crosswinds. Winds impinging crosswise on the bladed spoke increases drag, largely negating any gains achieved against direct headwinds on spokes positioned in the uppermost critical region of the wheel assembly. 

Crosswinds cause the effective wind vector impinging the upper spokes to change orientation with wheel elevation.  The wheel wind profile diagram indicates that a direct headwind varies in strength from at least twice the vehicle speed near the top of a wheel to near null wind speed at ground level.  However, any crosswind upon the wheel instead remains constant in speed with changing wheel elevation.  The combined wind vector — when the spoke is positioned within the critical upper region of the wheel assembly — changes from being directed from nearly straight ahead near the top of the wheel, to a more sideways orientation on lower sections of the spoke. 

The AeroTaper spoke profile optimizes the cross-sectional spoke profile for this varying wind vector, thereby minimizing wheel-induced drag on the vehicle; the thin bladed section near the wheel rim provides maximum streamlining for the magnified headwinds impinging near the top of the wheel, while the round central section provides optimum performance against relatively stronger crosswinds impinging lower in elevation within the upper wheel region. 

The wheel wind profile diagram also indicates that the slower-moving bottom section of the wheel contributes comparatively little to overall vehicle drag.  For this reason, the orientation of the spoke when positioned below the axle is insignificant, since it has little impact on total vehicle drag.

The optimal tapered profile of the AeroTaper spoke — from bladed near the rim to round profile near the wheel hub — will vary depending on the predominate wind conditions for each application.  An AeroTaper spoke tapering more rapidly minimizes overall drag when used strong crosswind conditions.  An AeroTaper  spoke tapering more gradually maximizes aerodynamic efficiency when used in light crosswind conditions.  Thus, in order to accommodate a variety of crosswind conditions, a selection of wheels using different AeroTaper spoke profiles may prove most useful to the road racing community.

The AeroTaper spoke design is currently patent pending.  Licensing inquires are welcome.  Contact Garth Magee at Null Winds Technology for further information.

About Null Winds Technology

Null Winds Technology was founded in Los Angeles, California, by Garth Magee in order to introduce innovative wheel drag-reducing technology, first to the bicycle world. Shielding a bicycles’ faster-moving upper wheel surfaces from headwinds yields dramatic increases in speed without sacrificing crosswind stability. And gains in pedaling efficiency increase in rising headwinds. Potential future applications for this patent-pending energy-saving technology include electric bicycles and automotive vehicles that have exposed upper wheels, such as industrial trucks.