Swiss Side internal wind tunnel test. The wheels and tires were tested on the Cervèlo Aspero.

Comparison of different rim depths and tire widths

In an initial test, we compared different tire widths on our GRAVON wheels at 30km/h and 45km/h.

The test results at a more relevant speed for gravel cycling (30km/h) showed savings of 2.4 watts when comparing the most aerodynamic GRAVON 500 to the less aerodynamic GRAVON 250.

An additional 2.5 watts can be saved by using a 35 mm tire instead of a 45 mm tire on the GRAVON 500.

When comparing the GRAVON 250 with different tires, savings of up to 3.1 watts can be achieved by using a 35 mm wide tire.

The same set-up was tested at 45km/h

We analysed the data for the most common gravel tire width, a 40mm tire (Schwalbe G-One 40mm), which offers excellent comfort, at 45km/h. The data show that up to 8.1 watts can be saved by using our most aerodynamic gravel wheelset, the GRAVON 500, instead of the GRAVON 250.

Even greater watt reductions were observed in a test of the same wheel (GRAVON 500) but with different tires at 45 km/h. Up to 9.8 watts can be saved by using the Schwalbe G-One 35mm tire instead of the Schwalbe G-One 45mm tire on the GRAVON 500.

The same tire-set up was tested on the GRAVON 240 in which a difference of up to 9.9 watts was observed.

Comparison of different tire widths at 30 km/h

The so-called "sailing effect" can be explained by analogy to a sailboat using side wind to move forward. The wheels capture the side wind and can even produce thrust to move the bike forward. In physics, this is described as negative drag.

We’ve intensively tested our aerodynamic gravel wheels in the wind tunnel with different Schwalbe G-One tires at various widths. To evaluate the wind stability and sailing effect of the rim, we tested at different side wind angles.

As shown in the graph below, the GRAVON 500 offers the greatest aerodynamic gain and the best sailing effect with the Schwalbe G-One 35c tire at 30 km/h. This advantage persists even as yaw angles increase. The greater the side wind angle, the greater the sailing effect and watt savings.

Comparison of different rim depths and side winds at 30 km/h

In a final test, we compared the different rim depths of our GRAVON wheels. The results also show that the greater the side wind angle, the greater the sailing effect and watt savings. In general, between 2 to 6 watts can be saved with the GRAVON 500 and the most commonly used gravel tire width of 40mm.