Time trial racers are usually sold as complete bikes with training wheels. However, to maximise the aerodynamic potential of the machines, aero wheels with higher rims and a lower number of spokes are actually indispensable. Typical for such wheels are rim heights of 60 millimetres and more, with disc wheels being the final option. The material of choice is usually carbon fibre to keep the weight in check. In addition to the height, the width has also increased in recent years: the rim rings are now up to 27.5 millimetres thick.
Aero tests on individual wheels have shown that the greater width can reduce the flow resistance of the wheels, especially in crosswinds. Among the spoked wheels, the Zipp 808 with the Firecrest rim profile has so far done this job best. Zipp's lead is presumably based on the fact that the Americans have made the most progress in the use of software for flow simulation (Computational Fluid Dynamics/CFD). The software supplements and replaces wind tunnel tests. Josh Portner, Technical Director at Zipp, explains why software is becoming increasingly important for development: "In the wind tunnel, we only see a result, but we don't see why something is happening. Flow software enables us to understand why something happens. This knowledge gives us a decisive advantage, because it is not as easy to copy as a rim shape." Is the lead still there? We want to investigate this question.
The test results of these competition wheelsets can be found below in the PDF download (this test is also included in the special "Time Trial and Triathlon"):
- Enve 6.7
- Enve 8.9
- HED Stinger 9 FR/Stinger Disc
- Mavic Cosmic Carbone 80
- Reynolds Sixty Six/Eighty One
- Reynolds RZR 92
- Vision Metron 81
- Zipp 808
Please also take a look at our special issue "Time trial and triathlon" from TOUR 5/2012, please follow the link below (including aero wheels test).
Downloads:
download
