Are you sure about the aero profile on the Trispoke? It is my rememberance that it was similar to the Spin model in that the spokes were essentially oval rather than NACA spec airfoils, and that in general, the wheel was not all that fast.

Chris

Thanks for the additional info, Tom. It's been a great many years since I have seen one at all, and I believe it was only during a race that I saw it then, so the wheel was spinning and I probably could not reliably infer anything.

I am not sure what to make of your 0 yaw data, other than to say that it's essentially irrelevant. I test a zero yaw just to see what happens, but I make all of my assertions as to what is truly faster from my windy condition data. This may not be the right thing to do where you are from, but around here, windless days only exist before 8:00am, and even then can be hit or miss.

Looking at my zero yaw data I have:

Nimble Crosswind with 20c Vittoria Corsa Evo CX = we will call this the baseline
HED 60 with 16 spokes and 21c Clement Criterium = +2 watts
Zipp 404 with 16 spokes and 19c Vittoria Corsa CX = +3 watts
HED 90 with 18 spokes and 21c Clement Criterium = +3

This is for the CarbonAero fork. Not normalized for reduced Crr of tires. The Zipp is the only one that MAY have a butyl tube. The others are confirmed latex.

Same bicycle (Kestrel KM-40) but with a Reynolds Ouzo Pro Aero:

Zipp 404 with 16 spokes and 19c Vittoria Corsa CX = we will call this the baseline
HED 90 with 18 spokes and 21c Clement Criterium = +2 watts
HED 60 with 16 spokes and 21c Clement Criterium = +2 watts
Nimble Crosswind with 20c Vittoria Corsa Evo CX = +5 watts

The Reynolds isn't the worst fork for the Crosswind, and the Oval is slightly closer (@ 4 watts) to the 404.

I forgot to mention that I tested the Look HSC 1 and HSC 2 forks as well. The HSC 2 is probably the best performing fork by weight, not that anyone cares too much about that.


Anyway, not sure there was really any point to this other than "what works for you is what works for you". This is the primary reasoning behind me only putting up the order in which things perform, rather than the magnitude of the differences. So many different things can effect the outcome that it's hard to make any inferences at all outside of the exact system you are running.

Chris

Any iteration of the Trek TT forks, or the current Quintana Roo forks both have the wider crown and leg spacing. As already mentioned the Blackwell Time Bandit and Kinesis Carbonaero should be good canidates. Finally, the Oval jetstream, though the vents are facing the wrong way, is a decent option due to wide spacing.

Will the HED3 not make that cool "fwah-fwah-fwah" sound as it spins in the right fork? How much energy do I lose for that?

-- Boris

To be honest, it's my opinion that the "fwah-fwah-fwah" sound is more a function of hearing the spokes pass through the contact patch region than any interaction aerodynamically at the fork crown.

Think about how any deep, hollow carbon rim has a constant "fwaaaaaaaaaaah" sound as you go along. This is caused by the road imperfections inputting vibrations to the rim and the hollow rim acting as a "sound box". With a normal spoked wheel, there aren't any dramatic differences in the vertical stiffness as the wheel rotates so you get the constant sound, but with a trispoke type wheel, that's not the case.

But, like I said, that's just my speculation....

Also, what exactly qualifies as a wide or narrow fork?
Does it mean the distance from fork to spokes/rim or the thickness of the fork front to back?

I have no doubt that both wheels are fast- the results of Cancellara are testament to the speed of the Zipp wheels-