Front Wheel Testing Blog
Aerodynamic drag has a significant contribution to an athlete’s resistance. As the athlete’s velocity increases, so does the power required to overcome their aerodynamic drag. An athlete must consider not just their body position but the drag of their frame and wheels as a dynamic system.
When an athlete is completing an individual time trial or a non-drafting triathlon, they will be exposed to a range of wind speeds and yaw angles. As such, the rider is subject to a decision as to which wheel should be utilised for their target event.
To demonstrate how a variety of wheels perform across different wind speeds and yaw angles, we tested a range of wheels, all of varying depths, profiles and spoke count in order to highlight the differences in power required (to ride at certain speeds), all of which you may expect to see when testing in the Sports Performance Wind Tunnel.
The speeds selected for testing were 40kph and 50kph, measured across 6 yaw angles: 0, 3, 6, 9, 12 and 15 degrees; to create a representative scenario of what a rider may typically encounter when riding or competing in a Time Trial or Triathlon.
The wheels were driven by the powered roller function to a wheel speed of 45kph.
In order to ensure repeatable data, there was no rider on the bike and the wheel speed remained the same throughout testing. Additional live edges of the frame and wheels were taken to ensure there was no deviation in the frame position over time. A spinning wheel tare was also completed prior to each run to account for any relative changes in mass of the frame and wheel set up.
The difference between the seven wheels was significant. With a near 15W difference between the fastest wheel and the slowest wheel at 12 degrees yaw/ 40kph and 30W at 12 degrees yaw/ 50kph. An interesting observation is 4 of the wheels followed similar trends with an offset, but the rest of the sample range performed differently across the yaw sweep. These trends were seen at both 40kph and 50kph wind speed.
In conclusion, the results from the test provide clear evidence that there is potential to find a significant reduction in aerodynamic drag when selecting the right wheel for your target event.
Please note that this data collection process occurred with just a frame and wheels. There was no rider involved. In order to present a clear image into the influence of the rider in this set up, further testing should be carried out.
If you would be interested in arranging a session in the Sports Performance Wind Tunnel to optimise your own equipment choices, please refer to the Performance Consultants section of our website for further information – https://silverstonesportshub.co.uk/consultants/