Carbon needs volume to reduce wall thickness (therefore most stiff superlight frames have big round downtubes). The torodial WTO shape will be lighter at the same height and width than the round V-shape they used before. The teardrop shape is the heaviest, as more material is needed to make it stable.
And the NACA (National Advisory Committee for Aeronautics) developed shapes for aircraft wings based on the teardrop shape. So, actually there is not
the NACA shape but many different ones. There are also curved shapes to cause lift.
For best crosswind stability the rim has to have a really sharp V-shape like a teardrop.
Bontrager measured the crosswind stability of their wheels compared to Enve and Zipp:
Aeolus XXX 2 | 5 Nm
Aeolus XXX 4 | 6 Nm
Aeolus XXX 6 | 8 Nm
Enve 2.2 | 4 Nm
Enve 4.5 | 7 Nm
Enve 6.7 | 8 Nm
Zipp 202 NSW | 5 Nm
Zipp 303 NSW | 7 Nm
Zipp 404 NSW | 8 Nm
Reynolds Aero 58 and 46 were both tested 1 Nm by Tour Magazine, Zipp 404 FC were 7 Nm...
Triathlon Magazine even called the Reynolds Aero 80 very stable in strong crosswinds.
The new WTO will save a few watts in high yaw angles but won't be more stable in crosswinds.
Reynolds also tried a toridial shape on their Strike wheels with a swirl lip generator to reduce side force:
https://support.reynoldscycling.com/tec ... -generator Doesn't work.
). What does this say about the medium to long term future of the classic Bora tubular range? At 1550g for the WTO 60 wheelset, they are a long way off the weights of Bora 35 or Bora 50s.
