Check the Hed web site. It turns out that BEST is relative to the speed you are traveling and the direction of the wind. Also, the tire rim interface has an enormous impact. For example the Hed Jet with Conti Attak clinchers has better drag numbers than the Sprinter with a tubular! But not if you use a different tire! The Hed web site shows drag vs wind direction and also has a wind direction gauge which can be adjusted for your speed. Cross winds are also a Big factor. In Kona my trispoke and anything over 6cm in the front moves me around too much, 148lbs. GT

thanks for the info really appreciated -- I was thinking about the weight issue and I think I am going to have to agree -- rotational weight is a huge factor -- more so I think than the relatively minor differences in performances among all these high end wheel sets.

XC runner couldn't have said it better. Most of us are convinced that an aero helmet and carbon wheels are the solution. How many people do you see with an aero helmet on 40 miles into an ironman sitting straight up on their base bar. Things like yoga, flexibility training, proper strength training, proper nutrition are what lead to true gains.

This is the argument I don't get. On hills greater than 4% (more commonly noted at 8% before the aerodynamic advantage of the heavier wheel is offset by decreased rim weight) how much accelerating do you expect to be doing? I understand the arguments concerning deceleration of the wheels due to frictional losses at the dead spot of the pedal stroke and the re-acceleration of the rim upon down-stroke. Namely, on a micro scale, the lighter rim is easier to re-accelerate than the heavier one. And this is true. However, the lighter rim also has less rotational inertia, so it's deceleration at the dead spot of your pedal stroke is more than a heavier wheel and you need to accelerate it more to get back up to speed. Also remember that this is on a "micro" scale. If averaged over the course of even a 1/2 mile climb at steady grade, these minute decelerations/accelerations will smooth out to a constant velocity, and as such, you will find that it takes the same power (or energy consumption) to move two bike/rider combinations of equal weight at equal rates of speed, regardless of wheel weight. It is the attacking on climbs where you want a light wheel; where you are rapidly accelerating on a macro scale. And here, you also want a stiff wheel that will not deflect like many of the ultra-light climbing wheels.

For more reading on this, see:
http://en.wikipedia.org/wiki/Bicycle_performance
http://www.analyticcycling.com/WheelsClimb_Page.html

There are other explanations out there if you do a search, but the best thing about the analytic cycling link is that you can actually put in values for aero and weight (which you can also find on the net) and see the difference in time saved/distance gained at a specific power.

I so love when XC800 chimes in, always a great read!!!

I'm still in the dust about wheels to get-best suited wheel for me, I'm thinking 404 set with powertap myself.