tire pressures?

I had 100 on the H3+ and 110 on the H3.

my guess is that 100 in the h3+ was too much. that is the max rating for the wheel per HED and with the more vertical tire walls, i'd think you'd want much less, maybe 90 max to get the same ride. not sure what is faster wrt that

Makes sense. I can tell you with 100# the H3+ rides like a dream especially compared to the H3 with the 20mm tire. What little wind I had today was either directly head or down wind so I am curious about how the H3+ performs with some moderate cross wind.

how wide is the attack on the h3+

I found a 23 SS to be about 24.4mm wide

I never thought the h3 with 20ss to be very harsh, really

your post reminded me that I am out of latex tubes. not sure where they all went other than I tried retiring my mich latex due to leaky valves

It measures 24.5mm. The harshness of the H3 is more of a reflection of the roughness of the road I think.

Thanks for the feedback. How large was the difference between Jet 6/H3+ and the H3? My personal guess would be that the difference is probably mostly down to the tire choice. The Attack could easily be 2-3W slower than the SS20 in Crr - plus/minus depending on the exact Attack you have. If you have a SS23 kicking and are feeling like running the test again, I would try mounting that on the Jet 6 and H3+. Or perhaps even better, just use the SS20 on those wheels also - optimally the exact same SS20 if you don't mind switching the tire over between runs.

FWIW I have tested my Jet 6 C2 (23mm brake track) against my H3 with the exact same SS20 and found them within ~1W of each other (i.e. within the margin of error of my testing).

Hed claims H3+ being at least equally aero as the H3 but with all the advantages of using wider tires:

https://www.youtube.com/watch?v=1TpLwxZY4_A

!!!!! I never knew this! Mine has been mounted wrong for 2 years LOL. How much time could that cost me? I've put up some fast tts with this wheel out front.

I agree. A better apples to apples test would have been H3 w/ 20mm SS vs. H3+ w/ 23mm SS at optimal pressures for each

Running the 20 on the H3+ doesn't make sense.... you're testing the "system", and one reason to go wider as a system is the better tire choices.

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This is one of the advantages to having them as a pair instead of just a front. It's hard to face the rear the wrong way (gears don't work so great that way!), so it gives a clue as to how the front is supposed to go.

I agree in principal, but an advantage from a testing standpoint in using the same SS20 is that you get rid of any difference in Crr that might be between tires. Now, the Crr of Supersonics in general doesn't seem to vary too much (like e.g. the Attack can seemingly do), but I have measured a SS20 that is quicker than a SS23 on my rollers. So if you were to use these two tires you would likely end up finding the H3/SS20 combo to be faster, which would then be down to Crr and not aero due to a sort of fluke tire(s). By using the same tire on both you get rid of that possibility.

And if your test says that the H3/SS20 and H3+/SS20 is equal, I would say there is little chance that the H3+/SS23 is not at least as fast, as long as the SS23 is not wider than the brake tracks (and you don't have a slow SS23 and a fast SS20).

I don't think you agree in principle, because that's the whole point. We already know the H3 is probably 1 watt per mm of width faster based on extrapolating from other wheel tests. And while tires may vary there's enough data to say on average the SS23mm, which is the optimal tire for the H3+ is faster than the SS20mm, which is the optimal tire for the H3. This incidentally may be why HED says their Jet+ rims are faster than their Jet wheels.

Further, the 20mm SS may not even be the fastest AERO wise for the H3+ if James Haycraft's tunnel data on SS20mm vs. GP4000s 23mm on a wide rim is any indicator.

Test the system. Test each individually and then do the math to compare. Wide rims are faster because any losses in aero are more than made up for in Crr.

Using the same tires testing methodologies to isolate is what led us to all the marketing red herrings... "our bike is great at 15 degrees of yaw!" "our tires are great at 15 deg of yaw!" "our bikes are so fast (but you can't get long OR low enough to actually go fast)", etc. It's why the Cervelo P5 comes second in every other manufacturer's tests.

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I definitely need to do a greater number of perhaps shorter loops. I was trying to get a hip shot idea of how the wheels compared so for the 10km loop I tried to maintain the same power. I was within a few watts on average for each loop. The Jet 6 and H3+ both resulted in the same time (within a few seconds). The loop with the H3 was 20 seconds faster. Maybe due to tire difference, non-optimal tire pressure, slight change in position (?).

See my comments above.

Thanks for the responds. 20 seconds or 2 s/km will be in the ballpark of 20W, which seems like quite a lot more than aerodynamics or Crr should be able to explain - even combined, I would say. So my guess would be that something else has likely changed.

Edit: Seems like I missed a factor of 10 in the wattage conversion at first - which is kind of significant :p

let me sort of clarify some of my findings.....

on different bikes, I found vastly different results with same wheel and tires(talking bike alone and only front wheel tire changes)

between a 20 and 23mm SS up front in low wind(ie 0 yaw) on an 808fc, the difference is definitely in the realm of oops someone left a quarter on the floor(0.2w at 30 mph) and trending much larger(relatively) with yaw with 20 being more aero at yaw

then again I did not find any tire to beat the 20ss up front at any yaw(of those I tried on the 808fc on a p3) with only the zipp tangent 23 tying at 0 and worse at yaw.

I also found the 20mm ss on the super 9 to preform best in back from aero perspective at yaw, but not at 0

that said, after taking into account aero and crr, I'd say 23ss f/r for me on the 808s probably optimal choice but likely pretty close to 20/23 combo depending on wind, but I am not good at estimating actual ground wind speed over the future course I will be riding as various fronts blow through and winds pick up or drop as day goes on.

now that I have hed wheels this year, I have no idea which tires will be best

conti attack was not a tire I tested.

on a p5-6 a 23 4000s was a dog both in tunnel and in real life. much different answer on a p3(with same front wheel)

This is it. Wheel/tire combinations will test differently depending on the bike and fork. Sometimes much different.

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which tunnel? I think James tested in a P5-6 as well. Jet 9 I believe as well.

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same as james. just different wheels between us

I had a flat in a TT 3mi in in 2014. returned to start and put 4000s wheel on in place of SS. based upon power and time over the portion of course before I flatted(even with the flat being a slow leak the whole time(ie slower than normal)) the difference by ROT was in the range of 10-15w( which correlates well with what I found in tunnel). wind did not pick up temps were slightly higher, wheel was in a sun baked vehicle(ie rubber warm already) I would not use a 4000s 808fc combo on a p5-6 for anything other than training purposes

wow, 15 watts? And you mean you went 3mi, flatted, started over with a new tire, and did the 3mi (and the rest of the course) again?

this is sort of what I'm trying to get at. You have Zipp Firecrests... Zipp told us that the GP4000s 23mm is the fastest tire for their wheel, and then it gets propagated around the internet. It has OK Crr, a puncture belt, so everyone buys them. But ACTUALLY, in YOUR bike, it's a dog. This is why I think testing the optimal for each component of the system and then comparing against another optimized system is the best way.

Curious though... James found the GP4000s 23mm to be pretty much equal to the 20mm SS if I recall.

At any rate, I'm pretty sure based on what you're saying a 23mm SS would be a good tire for Zipp 808s (and P5-6) especially at low yaw or on rougher pavement.

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my 23ss testing was on a p3 not on the p5-6, the 4000s did much much better on the p3 than the p5-6, not as fast as either SS but not to shabby. so yeah, frome/fork /brake and wheel/tire interactions all come into play.

yes to your question, I actually made it about 4 mi before realizing why bike was handling strangely. it was a leaky valve, not a puncture. I made sure valves were shut after that with a different extender. restarted and rode a time that was well off what it should have been, and on my best 40k watts in a long time. unfortunately, you don't get restarts in USAC so I got DFL in my category and lost out on my overall 5-peat for state TT.

the 4000s had a butyl tube, so that has to figure into the losses, but it was remarkably close to testing on aero once you consider tire and tube crr differences. yeah, some find 4000s to have better crr than others, but just as many find the 20SS ro roll faster from info shared with me.

btw, josh concurred than my results were not out of line when I inquired after the testing. I am thinking they just don't want folks riding 20mm tires on the808 for whatever business reason you can think.

I have said many times on here, the 4000s is not a magic tire

no but hopefully my magic attack is magic

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Interesting. So in my limited field testing yesterday I rode a Jet 6 (C2 not +) with a 22mm Attack, a H3+ with a 22mm Attack (different tire) and H3 with 20mm SS. The Jet 6 and H3+ performed about the same and the H3 was much faster watt for watt. I wonder about using a 20mm SS on the H3+ @ 90 psi.

Thanks for the info!! If you do any more testing, please post.