Just like many of you here on Slowtwitch, I have been very interested in HED’s new 2009 Stinger line-up of wheels. I even have a Stinger 9 and Stinger disc on order. Lately I have been playing around quite a bit on the aerodynamics and technology page on HED’s website comparing different wheels. Now this is a very useful tool if you believe the data. However, it seems they have added several new wheels to the mix and the HED Stinger disc data is completely different than what was posted just a few days ago. Has anyone noticed this as well. Is any of this data believable? Should I have just ordered some Zipps? It seems like this website is in an unfinished state as the old wind yaw calculator has been broken for some time. Also has anyone heard of the H3 with a C2 rim. I thought I saw someone post that this wheel is in the works. I think this would cure a lot of issues with the H3, needing super skinny tires to reach maximum effectiveness. This could be an actual evolution of a true gold standard in cycling.
I believe they revised the shape of the 2009 stinger lineup, and recently updated the website with the 2009 data.
i have to say some of the zipp data is suspect on there, could the sub9 disc really be that bad?
a disc cover isn’t that bad!
=)
also interesting is the zip 1080 tubular looks reaaally nice but the zip 1080 clincher looks horrid. that seems suspect.
Hard to say about the numbers on the HED site. I would take them with a grain of salt. That said. I have no douibt that they are very fast. But one thing it does do is it pushes the scale in favor of the tubbie crowd. (lighter, less RR, and way more aero too)
H3 C2? I heard that due to the cost and difficulty of making new molds, these were a long way off.
We don’t know how the rolling resistance benefit of the JetC2 compares to the aero advantage of the stingers.
The two wheels might perform similarly overall
to me those are just numbers on a web page. We have no idea how those numbers were calculated. Until I see a paper in a journal, its all a bunch of just numbers with no real meaning.
Its a valid point but if you wait for a paper in a journal you may never ever have any data at all =)
biketechreview might get something done I guess.
In the meantime you can usually get some hints at what is going on when you compare the data zipp publishes with what hed publishes.
where they agree, you are probably on to something.
to me those are just numbers on a web page. We have no idea how those numbers were calculated. Until I see a paper in a journal, its all a bunch of just numbers with no real meaning.
The difference in the tubular vs. clincher 1080 is that the tubular version has the toroidal shape all the way through the brake surface like the Stinger models, and the clincher model still has parallel sidewalls.
Chris
We don’t know how the rolling resistance benefit of the JetC2 compares to the aero advantage of the stingers.
The two wheels might perform similarly overall
we don’t even know if such a benefit even exists…
we also don’t know if the Stingers have less Crr than a conventional tubular rim. Lot’s of questions… Unfortunately, I don’t have any answers, though the Stingers seem to look really good–as do 808 and 1080 tubulars.
i promise to look into all of these question when i win the mega lotto =)
.
I have a difficult time believeing that the C2 rim makes that large of a difference in rolling resistance. Just based on the HED wheel data for their own wheels, the C2 rim would have to reduce rolling resistance by at least 3-5watts to equally the aerodynamic adavantage of the stingers.
At certain wind angles, the RR would need to decrease by about 9 watts. That seems impossible.
Does anyone know how many grams equal a watt? I recall reading something like 9 watts per gram. I’m trying to put HED’s data into something i understand.
What is a normal ammount of tire rolling resistance in terms of watts?
edit: Bike Tech Review shows about 13 watts per wheel for a good clinher tire.
Thats 26 watts total
C2 reducing that by 9 watts does not seem impossile.
But, I agree we have no reason to believe any improvement to be true either.
More like 9 grams equals a watt. Wish it was the other way.
What is a normal ammount of tire rolling resistance in terms of watts?
edit: Bike Tech Review shows about 13 watts per wheel for a good clinher tire.
Thats 26 watts total
C2 reducing that by 9 watts does not seem impossile.
But, I agree we have no reason to believe any improvement to be true either.
remember, you have to read those notes at the top–it’s probably closer to 20-25W for wheel on actual roads. That said, I’ve tried to pick out a difference in Crr (on a metal drum) between the wide rims and a regular width rim. They’ve tested faster–then slower, both times by very small margins. I doubt there’s very much difference.
OTOH, there seem to be significant differences between the tubulars and clinchers; the tubulars look much faster across the board. I’d be curious to know what tires where used in all of these cases.
Also, in looking at the data, why in the world would someone use an H3deep over an H3?
roady, when you did your tests, did you play with tire pressures? Don’t the C2s supposedly allow for lower tire pressures to be used?
That would probably only be an advantage on a non smoothe drum though
roady, when you did your tests, did you play with tire pressures? Don’t the C2s supposedly allow for lower tire pressures to be used?
That would probably only be an advantage on a non smoothe drum though
I did, but as you suggest, I’m not sure the metal drum results are worth much w/respect to pressure. The lower the pressure, the worse the Crr–so I tested at the same pressure to make the comparison.
I guess Hed’s argument could be that on the road, the C2 rims @ 100 psi would have lower Crr than a regular rim @ 115 psi–but they’d need to provide a convincing testing protocol for me to believe that’s true. As far as field testing this out, I think the differences are so small that it’s outside of the sensitivity of the measuring devices.
The stinger disc on the aero page was pre production the one that Bjorn used at a few races last year. The revised data is the new Stinger disc shape as it is in
production today. Also of note is that the discs are tested with the cassette on so they do not look as good as the front wheels. If you test a rear wheel with a cassette on it will always be slower than a front wheel. I dont think any other manufacturer tests rear wheels with cassettes on.
Thanks Jason. That clarifies quite a bit on the Stinger disc data. Does this mean that HED tested the Zipp Sub 9 with a cassette? Is this why the Sub 9 looks mediocre on HED site? Also if the numbers are indeed accurate, the Xentis Mark 1 TT looks absolutely horrible aerodynamically.
Yes and correct!
roady, when you did your tests, did you play with tire pressures? Don’t the C2s supposedly allow for lower tire pressures to be used?
That would probably only be an advantage on a non smoothe drum though
I did, but as you suggest, I’m not sure the metal drum results are worth much w/respect to pressure. The lower the pressure, the worse the Crr–so I tested at the same pressure to make the comparison.
I guess Hed’s argument could be that on the road, the C2 rims @ 100 psi would have lower Crr than a regular rim @ 115 psi–but they’d need to provide a convincing testing protocol for me to believe that’s true. As far as field testing this out, I think the differences are so small that it’s outside of the sensitivity of the measuring devices.
In my field testing lower psi on the road always resulted in higher Crr. With extremes (80psi vs 120psi) the margin was huge…like 13W with no position changes. I’ve yet to see a single test anywhere that supports the conventional wisdom that lower pressure is lower Crr on a road.