Superteam S-All Carbon Ultra Wheels Drag Wind Tunnel Test

In September 2024, we sent the S-All-Carbon Ultra wheels to a place in the United States to test the drag of the wind tunnel and also sent a pair of Standard 25mm Wheels (this is a pair of flat rim wheels) for comparison.

The wheels sent are as follows:
1. S-ALL Carbon Ultra Wheels

2. Standard 25mm Wheels

Wind tunnel testing location:
Andrew L. Banka, PE
Airflow Sciences Corporation
12190 Hubbard St.
Livonia, MI 48150, USA

Wind tunnel testing proposal:
All tests will be performed in ASC’s in-house wind tunnel, which has a cross-section of 17” wide by 34” tall. The wind tunnel has an upenerstream settling chamber with flow straighteners and turbulence screens, and an 8:1 contraction into the test section, providing low turbulence and an even velocity profile. For a 700c tire with a width of 30mm, the blockage in the test section will be an acceptable 5%.

A ground plate will isolate the wheel from the boundary layer on the tunnel floor and provide a representative ground interaction. The wheel axles will extend through the wind tunnel walls, where the drag force will be measured using load cells. The wheel will be non-rotating, and all tests will be performed assuming a straight-on wind (no yaw angle). All wheels were tested with tires installed.（Continental ULTRA Sport 3 700X28C）

The ASC wind tunnel is equipped with transparent panels on one side and the top of the wind tunnel to facilitate observation and collection of still and video images. Images will include set-up photos as well as still and video showing smoke flow around the tire/wheel combination. Tests will be performed at 30, 37.5, 45, 52.5, and 60 km /hour wind tunnel velocities.

Test process：

1. Put the tire on the wheel and pump it to the appropriate tire pressure            
2. Attach the wheel to the axle and center it in the wind tunnel
3. Align the axle to gently rest the dynamometers on both sides of the wind tunnel
4. Set the wind tunnel to the desired speed
5. Collect data for 10 seconds
6. Collect data at all desired velocities
7. Take the wheel off the axle and repeat these steps against other wheels

Test results：
The following graph shows the drag and drag area of ​​the front and rear wheels at all speeds.

Drag is quadratic with speed. The wheels have similar drag at low speeds, but the difference increases at high speeds. The Standard 25mm Wheels have more drag, and the S-ALL Carbon Ultra Wheels have less drag. The rear wheel has more drag than the front wheel because the rear wheel has a wider hub and is exposed to the wind longer.

The drag area of ​​both wheels decreases with increasing speed. Again, the Standard 25mm Wheels have the largest drag area, while the S-ALL Carbon Ultra has a smaller drag area. The rear wheel has a higher drag area than the front wheel due to its extra area.

This is because the Standard 25mm Wheels is a flat wheel, and the flat wheel has a smooth rim, so the drag area is small and the drag is large; when other conditions are the same, such as speed and airflow, the S-ALL Carbon Ultra has a special shark fin pattern, and the larger the drag area, the smaller the drag.

Conclusion：
The results show that the drag force for both sets of wheels varies between ~0.60 N and ~3.00 N. This range of force corresponds to a range of drag area, from ~0.0125㎡ to ~0.019㎡. The drag area generally decreases with speed. The drag force of the rear wheels is always higher than the front wheels within the same set. The Standard 25mm Wheels have the highest drag force, and the S-ALL Carbon Ultra Wheels have the lowest drag force.