1. Introduction

On June the 8th , 2019, a 4^th session of wind tunnel tests took place at the GST Windkanal, in Immenstaad, Germany.

This time the purpose of these dry runs was to test the first sample of the new 34 Aero Wide Disc alloy wheel against some of the best competitors on the market.

Below the list of competitors wheels:

1. ZIPP 30 Course
2. ZIPP 202 NSW
3. DT Swiss ER1600 Spline 32
4. Mavic Cosmic Elite UST

All the tests have been carried out considering wheels alone and not any bike this time and rotating the wind tunnel platform from -20° to +20° at 45km/h as usual.

All the tests considered a Schwalbe Pro One 25mm but the 34AWD and the ZIPP 202 NSW have been tested with the 28mm versions as well. 

2. Description

Following all the configurations tested:

3. Test Results

All the test results have been reported in the form of graphs representing the drag force of each wheel model, on the Y axis, vs the yaw angles, on the X axis.

As additional information, tables with the average aerodynamic power [Watt] that a rider expends to achieve and keep 45km/h differential speed in driving direction are reported.

The power is corrected and normalised.

Corrected means the test rig is removed; normalised means the calculation is valid for exact 45 km/h differential speed in driving direction with standard conditions (p = 1013 mb, t = 25°, rho = 1,184 kg/m3). Differential speed means driving velocity minus wind velocity in driving direction

(The formula is only valid under the assumption that the measured coefficient of drag for small changes in speed is independent of the Reynolds number.

±2.5W is the error repeatability of the wind tunnel).

4. Conclusion

As we can see from the data above, the Hunt 34AWD is overall the best aero alloy wheel tested, and it is also better than the carbon ZIPP 202 NSW when considering a 28mm tyre.