For race wheels, I'd go Conti Supersoniocs (23mm front, 25mm rear) for a fast setup.

If you want some extra flat protection (and a slight increase in CRR), go with the GP4000S II (same sizes).

The 23 will be slightly faster in front due to the better shaping with the rim. The 25 will be faster in back due to the lower CRR (the rear has more weight on it, and is shielded by the seat tube).

As for pressure:

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The Supersonic is only made in 20c and 23c sizes. The 23c seems to be aero enough to more than overcome the width difference to the 20c with its improved Crr.

Of the Conti options you mention the Attack is probably one to avoid as Crr testing has shown a wide variance. It is also a very narrow tire and you are going to wider rims. The Force has shown to be a consistently low Crr tire and would be a good rear tire option. So maybe GP4k2 23c or GP TT upfront?

Supersonic is fastest option, but is currently harder to come by than the Turbo Cotton.

Watch the video on how to mount tires on Hed rims before you try. Also max inflation is 100. If you dont watch the video you will have a hard time mounting any tires at all. If you cant mount the tires with your fingers you are doing something wrong.

I run gp4000s in 23 but they measure 26 mms on Hed Jets.

How about running them tubeless and using Vittoria Corsa Speed 23mm?

I run the 22mm Attack up front, and the 23mm GP4000sII in the back. My bike guy says that HED had said the 4000sII tested out the fastest. I hit 58 mph on a downhill at Whistler last month with the set up, for what it's worth. I'm 170 lbs, and run the pressure at 90

Thank you all for the recommendations. I settled on the Conti GP 4000 S II 23 mm front and 25 mm back.

You do realize HED recommends the Attack for their HED Jet+ wheels correct? This is because it tests most aero of the tires they tested. In addition, wider rims, balloon out the tire even further. A 22mm attack likely measures 24-25.5 when broken in.

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I guess 23mm front is ok but you would probably be better off with the Attack. The problem with the HED Jet+ is the rim is so wide that it really balloons out the tire. The 25mm tire is going to be huge, like 30mm when broken in, while the widest part of the rim is going to be about 26mm. The 23mm will likely be 25.5-27mm when broken in. HED recommends the Attack. I would go with a Supersonic myself.

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Nope. The aero properties of this tire alone are only part of the performance equation. I clearly qualified why I don't recommend the Attack based on widely varying past Crr testing results. Several other consistently better rolling options available that aren't going to be a lot less aero.

Do you have HED Jet blacks by chance? The reason I bring this up, is that unless people have HED Jet+ rims, they don't realize just how big these tires balloon out to. There are couple of data points out there on the Attack, but I would not consider the variance in the Attacks to be set in stone - it could very well be bad luck.

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So, in light the comments in this thread, I am going to do a couple of things and then report back. What I will do is this: (1) install the 23 mm and 25 mm Conti GP 4000 S II tires and measure the width of the tire on each wheel at pressure--this will take some time, because I won't receive the wheels for a couple of weeks; and, in the meantime (2) contact HED and ask what tire + width + PSI HED recommends.

I do appreciate everyone's input. Thank you again.

No. Zipp 808's and Super9 clincher.

Tom Anhalt has several data points for the Attack. Some are averaged and some are single tire values. The spread in just the samples he's tested is 5-7 watts (front and rear) from slowest to fastest at 30-40kph. That's too much variance IMO. Others may disagree which is fine. You have to run what you're comfortable with using.

Historically the GP4000S did not roll well and the tire improved over time. Maybe the same thing will happen with the Attack and there will be a consistently fast rolling narrow/aero tire available eventually?

Similar to looking at the Attack 22c for the front HED Jet black, I ran the 20c SS up front on the 808 for a while, but it gives up substantial Crr to the 23c SS which isn't a lot less aero. So now I run 23c front and rear. If I'm really worried about a course from a debris standpoint I'll swap the 24c Force on the Super9. But I'm doing that less often.

Ok well let me know what they say. I periodically check with companies to see if anything has changed but have not in a while. They have always refommended the Attack at a max of 100 psi.

There is a good article on ST by Greg K re the Hed Jet+

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Looks like another data point on the Attack just done:

http://www.bicyclerollingresistance.com/...and-prix-attack-2016

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Comparing percentage-wise to my own results (which isn't totally valid due to the fixed offset of butyl vs. latex tubes used in the testing), it appears he got one of the slower Attacks rather than a "magic" one...

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For what it's worth, here's my Vittoria Corsa Speed mounted tubeless at 100 psi on a HED Jet Plus disc. It measures 27mm.

22mm Attack on Hed jet Disc plus is 25mm.
23 Conti II is 26.5mm
25mm Conti II is 28mm (this actually look funny)

22mm Attacks look more flash with rim (side is flat not round/baloonish) , 23mm Contis are wider than rim (side looks like balloon)

Contis are more puncture resistant.

I have front old 23mm Hed Jet 9 with 22mm Attack
rear Disc jet disc plus with 22mm attack.

for training I swap disc with Hed jet 9 and 23mm Conti tire, both setups have latex tubes.

Hed says Attacks are more aero (I suspect due to flat sidewalls with braking surface - less air turbulence)

https://www.instagram.com/p/BG9vFiQy6Aq

So, I talked to HED. The recommendation was 22 mm Attack in front, and 23 mm GP 4000 SII in back. Forgot to ask about PSI but at my weight (165 plus/minus) I am thinking 95 PSI.

Interestingly, HED also suggested not using latex tubes. We debated that a bit and the final advice was "your call."

Tom Anhalt has several data points for the Attack. Some are averaged and some are single tire values. The spread in just the samples he's tested is 5-7 watts (front and rear) from slowest to fastest at 30-40kph.

Out of 5 samples I've had 1 Attack that tested as bad as a typical GP4000. One was really good (as good as a 23mm SS). The rest were "normal". All tires have a decent amount of variance in Crr. All Conti's good clinchers have the same casing and Black Chili tread compound. The difference is in size, tread thickness, vectran belt (or not), and tread grooves (or not). For Crr the order starting with the best is, Supersonic, GP TT, Force, Attack, GP4000. Aero is a separate consideration.

For typical yaw (low) the fastest tire is probably the 23mm SS. Maybe even a 20mm SS, but I'll assume you aren't considering that. All "open tubulars" suck for aero. It might make sense to consider a Vit Corsa Speed for the rear, but never the front.

GPTT you mean? The 23mm SS is quite a bit smaller than the 23mm GPTT. Barely wider than the Attack.

I'd turn the Attack backward on the front. And the Crr advantage of the GPTT 23 should make it a better choice than the GP4000S on the rear.

Can't imagine why they recommend against latex unless it is a CYA move for all the people who don't know what they are doing.

Every bike shop around me doesn't carry latex. Or if they do carry it, it's two tubes that have been on the shelf for 5 years, and they all tell me "we got those for one customer and they couldn't stand them, I wouldn't recommend it".

Yep exactly, although slightly surprised by 23mm GP 4000 on the back. Nobody is going to recommend latex, it is a CYA thing. Latex is faster, and I wouldn't dare run a GP4000 on the back.

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As I mentioned, I run the Attack up front and the 4000sII on a back disc. I can't tell you how stinking fast that set up is compared to everything else I've tried. Why would you not dare to run the 4000 in the back? Just curious

Regarding the latex, I had major flat issues for a couple of races with the latex tubes. Thought I had it remedied for Whistler, then flatted the back wheel towards the end of the race. Last race I ran latex up front and butyl in the back because I was a wuss. No flats at least!