With the tire and internal rim width selected, we used an advanced CFD algorithm we developed after collecting more than 100,000 on-road measurements to develop a rim shape. Most people think that the deeper the rim, the faster it is. That is not always true. A great rim profile will blend aerodynamics and stability in the wind by striking a balance between the depth and width. This is exactly why our new FLO 77 AS (77mm deep) is faster than our original FLO 90 (94mm deep).
When we develop a wheel, we give our algorithm a range of wheel depths to create the rim’s shape. As the algorithm gets more advanced over time, we find that shallower wheels tend to settle on the upper limit of the depth range, but deeper wheels do not. For example, the FLO 49 AS had a range of 40-49mm and settled at 49mm, the FLO 65 AS had a range from 55-65mm and settled at 64mm, and the FLO 77 AS had a range of 70-95mm and settled at 77mm.
Developing a wheel with the lowest drag value does not always produce the fastest wheel. You must also consider the stability of the wheel in wind, especially when looking at the front wheel. When you experience a cross wind, the front wheel wants to twist. This yaw torque can make a wheel very challenging to ride. To make a wheel fast, you want it to feel stable, producing a confident rider who can stay in the most aero position and not have to fight the front end to stay on the road.