The thing to remember here is what wind angles are you measuring the wheels at? I'm not sure what flow regimes Slowman is referring to, but from our historical testing as well as the testing done independantly by Tour magazine and Hed's own data, modern toroidally shaped wheels like the Zipp 808 and the new Hed Stinger 90 best the H3 at wind angles less than about 20-22 degrees. Our own design with the 808 really focused on finding speed between 10 and 20 degrees of yaw (theoretially 60+ percent of all conditions), and with about 18 months of design time and 60+ hours of wind tunnel time we developed the current 404 and 808 rim shapes which are faster than the H3 from 0-~22 degrees of yaw. The new Hed stinger 90 uses a slightly different shape and deeper rim and is more aero than the H3 below 15 degrees of yaw according to both Hed's own data and data we have taken on this wheel at Allied Aerospace.
The H3/Specialized/Dupont wheel is extremely fast, and for the longest time has been the gold standard in aero front wheels, but the last 4 or 5 years have really seen an explosion of technology in rim shapes, spokes, manufacturing techniques, etc. that allow us to produce wheels that are now faster at moderate yaw angles. Past about 22 degrees of yaw, the only thing competitive with the H3 is a disc, which is considerably faster, but you definitely won't be riding the disc as a front wheel at that wind angle! The key to this low drag is that at high yaw angles the drag is purely a function of surface area, something that a 3 or 4 spoke wheel has in spades over a deep or very deep section wheel.
The issue for us is that to acheive 22+ degree wind angles, you need considerably high wind speeds to the point that many if not most people will choose not to ride the wheel for handling considerations. This was one of the major factors in our decision to stop producing 3 spoke wheels some 14 years ago now. Statistically, the 22+ degrees of yaw condition occurs less than 25% of the time, so I really would see a wheel like the H3 or Zipp 3000 3 spoke occupying a place in the wheel arsenal as being a windy day only wheel for those who are comfortable riding it in those conditions. For the other 75% of the time you will be faster on a toroidally shaped very deep section wheel (the patent co-owned by Zipp and Hed) or even a hybrid-toroidal shaped deep rim (the zipp specific patent) which will be aerodynamically faster as well as have considerably less side-force and steering torque due to decreased surface area.
I am yet to test the Blackwell 100 rim, but it is interesting in that John has put some waves in the sidewall to try and control the airflow without infringing our patents for rim shape, I'm not sure if this will have the effect of recapturing the air that is described in the patent but is an interesting concept and we will be taking one to Allied in a few months with some other R&D wheels we are experimenting with.
We have all of this published in a white paper (5 white papers actually), as well as the Tour magazine test reports, that most Zipp dealers should have, but it is not available online at the moment as we are putting our new website up today and everything is a big mess.
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