A note on Spoke Count in Aerodynamic Bicycle Wheels

Since the advent of the modern deep section aerodynamic bicycle rim, there have been numerous and often divergent theories about what constitutes an aerodynamic spoke configuration. Theories even arose in the mid 1980’s thinking that higher spoke count wheels would force the air to move around the entire spoked area of the wheel, causing the wheel to behave similar to a disc. This particular theory was quickly thrown out as field studies showed riders on 48 spoke wheels working hard to keep up with those on 28 spoke wheels, but many disagreements and discrepancies still remain. By the late 1990’s, the big debate seemed to relate to how few spokes one could feasibly use, and whether the spokes were best shaped round, oval, or flattened. Another raging debate was occurring between rim and wheel manufacturers as to whether hidden or exposed spoke nipples were more aerodynamic, as well as possibly stronger. The information represented below is the culmination of physical study on bicycle rims and wheels undertaken over the last 4 years specifically, and the wind tunnel information relates to a 50 hour session occurring in January 2004 at Texas A&M University LSWT, during which these issues and others were specifically tested.