I don't just pedal harder. I may also focus on staying in the aero position longer and make myself more slippery.

---

Duke

Thanks. But, that paper didn't address the question at hand. It simply said that cycling power (total power that included the rider) can be modeled with about a 3 % error. No attempt was made to look at the bike frame component at all, which is what is being discussed here, as I understand it. That paper simply does not address the issue I brought up.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

It figures that you would attempt to obfuscate things so as to cover up the fact that you were wrong.

Here is what M~ originally asked (emphasis added):

"What is the difference between wind speed and speed of bike/rider? What I mean is when they say they were tested with a wind speed of 45/h, does that mean that is like the bike going 45/h on the road?"

Here is what you said in reply (again, emphasis added):

" There is quite a bit of difference between wind speed and when the bike is moving to cause the "wind". Wind is laminar and the speed increases as the distance above the ground increases. Riding into the wind the speed of the wind is the same 1 inch above the ground and 10 feet above the ground."

So, don't go trying to claim that the question pertains to bike-only tests...

(BTW, the S.E.E. was 2.7 W, which was only 1-2% of the mean...this is not "about a 3% error" as you erroneously stated.)

speaking of obfuscation, the OP then wrote, which you conveniently left out: "Or is this wind speed just used to test the drag of the frames. Do some frames do better when the wind speed is lower or higher?" That part of the OP's post went to the frame alone. The question also came up in this thread as to why certain bike manufacturers would not want to participate in a wind tunnel challenge to determine frame aerodynamics. Reading my answer that you copied does deserve a little clarification however. What i should have said is: Riding into still air, the speed of the perceived "wind" is the same 1 inch above the ground and 10 feet above the ground. My comments regarding the usefulness of the paper you referenced to address this question stands.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

On the contrary: since there is a boundary layer during wind tunnel tests, the fact that you can use wind tunnel data to predict the power requirements of cycling outdoors with such precision demonstrates that the impact of such a boundary layer is - as I have said all along - inconsequential.*

*As can also be demonstrated by simply reading the wind tunnel specifications found here:

http://lswt.tamu.edu/...ance_Characteristics

which report that the boundary layer is only 1.5" thick, i.e., way below any frame member on a bicycle.

What are these changes in position and, at the moment that you're on the bike collecting the data, how do you know that they lower rather than raise CdA?

Oh, phooey. That might be true if one were looking at the bike frame alone on the road and in the tunnel. But, when there is a rider on the bike these changes from the bike frame, especially those that are only close to the ground where these differences are more pronounced, are going to be so small that it is unreasonable to conclude that data that looks at the rider and frame together (where the vast majority of the drag is coming from the top tube of the bike up) is so sensitive to pick up this small effect. Perhaps your 2% error is due entirely to this effect. That would suggest that if one were to look at the frame alone the error would be much greater.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Man can land on the moon and you think man can't figure out that a bike frame is faster?

Dude, it is common knowledge that the moon landing was staged. You are so gullible. ;-)

Maybe it wasn't staged; maybe it was a placebo effect.

Maybe it wasn't staged; maybe it was a placebo effect.

Well since we really wanted to get to that sexy new moon you are probably right. I bet they were a lot slower coming back to this old boring planet.

You should use your connections and create a DVD on bike aerodynamics and the relationship to power production. I think the only way for people to appreciate this subject is to understand it visually. You could probably work with A2 (since they seem to be eager to get their name out there) or the one in Colorado. I'm quite sure you could sell that DVD. After all tons of people pay $20+ for a dvd just on transitions. Get to it, bro!!!! I'll take my 10% if you make any money. ;-)

If we act now, we can probably get stimulus funds for the aero testing. What is $30K for the government? Can we all stop arguing and write a proposal?

This is really silly.

It's not just silo-ization of the bike and it makes complete sense. Sure, there are a tons of variables that go into a race that can affect the overall time of the athlete. But by your reasoning, there's no reason to worry about which wetsuit fits me best and is therefore fastest. It's only going to make a difference of a few seconds and I could easily lose that because I stumble on the way out of the water. There's no reason to have my shoes clipped in to my bike since that's only going to save me a few seconds, and I might lose that because I didn't train enough on the bike. There's no reason to use the most aerodynamic frame I can afford, because that's only going to save me a few seconds and I might lose that because my position isn't optimal. There's no reason to use yankz or speed laces because those will only save me a few seconds and I might lose that because I didn't hydrate adequately. And on and on and on.

Everything from training to pacing to race day conditions will affect your time, but the equipment you select is completely independent of all of those factors and will save you time in every single case.

I'm pretty sure you missed the point by silo-izing your response!

Everything from training to pacing to race day conditions will affect your time, but the equipment you select is completely independent of all of those factors and will save you time in every single case.

That's right.

My point was that people seem to overly analyze everything related to the bike here almost the exclusion of everything else.

---

---

Steve Fleck @stevefleck | Blog

Please see my edited comment. I'm thinking how a placebo effect may have on ME if I conduct a similar test. Not knowing any details of Tom A.'s testing, I asked him if he could be biased. It was a question and not an attack on his testing and note that I didn't argue with his reasons.

---

Duke

I did not interpret your question as an attack, nor should you interpret mine as an attack. Since Tom has linked to a thread where many of the details of the test procedure have been discussed, I'm asking about the mechanism by which a placebo effect could both explain the size of the observed difference and be undetectable.

Really?

Do a search on "running" and "pose method" or "chi"...or on "high arm" and "swimming"...and tell me how many threads come up ;-)

Also, in a typical tri, isn't more time spend cycling than either swimming or running?

---

http://bikeblather.blogspot.com/

--------------------------------------------------------------------------------
I think first of all bikes are built to be ridden by an athlete. With a test without rider we know now a Scott alone in the Windtunnel is the best choice. If you have alot of races like this on your schedule, the buy it. If not, then you have to wait for a serious test with a pedaling rider on the bike. But:

Fuer die abschliessende Bewertung der aerodynamischen Qualitaet haben wir daher nur die reproduzierbaren Messungen der nackten Raeder ohne Fahrer verwendet.

makes not so much sense.

Did you read the whole test? Then you would've realized that the bias was just to high with rider. The only rational hing to do is to put a kind of plastic dummy on the bike. But obviously there's no bike/rider interaction aerodynamic wise, so you just can test the bike alone.

Btw: I don't wanna offend you and many others but this kind of post of know-it-alls, who try to sell their half knowledge makes 80-90% of all those posts here rather useless. I rather trust a renowned bike magazine than anonymous slowtwitch posters :-)

Yes, for sure if the differences between each frame with rider have been too small to come out of measuring tolerance, there is no interaction from the rider to the frame aerodynamic wise and we can measure the bike alone. And the difference between riding against wind or standing air we can forget completely.

But weak people still better wait for a test with real experts, who do not sit on the bike with the most wrinkled winter suit I ever have seen, fleece gloves and neoprene ear warmers under the helmet. And if they think they have to do a test in a tunnel, maybe they find one next time with adjustment of the temperature to bring the character of the air flow to a normal race level.
But til then we know that in winter air a Scott without rider is the best choice. No more.