The Powercrank Thread

[FrankDay]

There is that and other practical issues like dealing with wheels that go out of true or break a spoke.

More to the point though are the scope of performance improvement they claim which, like yours, are implausible.

Why is it so implausible? they chose the best scenario to see a benefit, a high headwind, which would magnify the benefit.

e.g. they claimed one novice level rider gained a 20% speed improvement while riding into strong headwinds at same power*.

If that were true, it would require these fairing to achieve the remarkable result of halving the total bike and rider CdA (coefficient of drag).

Really? If we are riding into a 35 mph headwind at 10 mph the rider is seeing a 45 mph headwind, and the spokes (which are moving forward twice the bicycle speed) is seeing a 55 mph headwind. According to analytic cycling riding along at 10 mph at 0.4 CDA requires 26 watts and a 10% improvement to 11 mph requires 3 watts more. But, to ride along at 45 mph requires over 1000 watts, and a higher percentage of that wattage is coming from the wheels than at a slower speed (it is why the fast guys like aero wheels so much). Seems that fairing the spokes could help quite a bit in this circumstance at a 10% speed improvement might be plausible, after all, HPV's fair the wheels (and other things) and can achieve speeds of 80 mph in calm air at the same power. Now, they didn't control for rider position but you guys are really good at claiming something as being impossible without actually trying it yourself. Fairings are not gimmicks, as they were referred to. While you may find the claimed improvements implausible, I think you would be better off not claiming them impossible, without more data.

But hey, if a rider goes faster, what does it matter if it's because of things other than the device used? May as well claim it anyway, eh Frank?

So, are you trying to say that wheel fairings don't work? Might try telling that to the HPV community.

I sent them some comments via twitter, but not surprisingly, my comments don't appear in their twitter feed.


* note the use of an ibike Newton for power data.

It seems to me that the iBike might be a good PM for this "experiment" since using a regular PM doesn't allow one to know that the headwinds are the same for the two rides. The problem is, of course, we still don't know if they controlled for headwinds so it probably would have been better if they used a regular PM and the iBike meter so they could know the bike power and the headwinds were the same for the two runs. It would be even better, of course, to have done this in a wind tunnel, where the drag difference could be better quantitated because power there doesn't matter. I wouldn't claim their testing as being very rigorous but, they did what they did and, it seems, didn't try to lie about it, publishing their results. You may not like it but it hardly seems worth such derision for a product aimed at the commuter market, trying to make it easier for people to ride into headwinds. And, it hardly seems appropriate for this thread where there is actually some real science that could be discussed specific to the product in question.

 

[Alex Simmons/RST]

Why is it so implausible? they chose the best scenario to see a benefit, a high headwind, which would magnify the benefit.Really? If we are riding into a 35 mph headwind at 10 mph the rider is seeing a 45 mph headwind, and the spokes (which are moving forward twice the bicycle speed) is seeing a 55 mph headwind. According to analytic cycling riding along at 10 mph at 0.4 CDA requires 26 watts and a 10% improvement to 11 mph requires 3 watts more. But, to ride along at 45 mph requires over 1000 watts, and a higher percentage of that wattage is coming from the wheels than at a slower speed (it is why the fast guys like aero wheels so much). Seems that fairing the spokes could help quite a bit in this circumstance at a 10% speed improvement might be plausible, after all, HPV's fair the wheels (and other things) and can achieve speeds of 80 mph in calm air at the same power. Now, they didn't control for rider position but you guys are really good at claiming something as being impossible without actually trying it yourself. Fairings are not gimmicks, as they were referred to. While you may find the claimed improvements implausible, I think you would be better off not claiming them impossible, without more data. So, are you trying to say that wheel fairings don't work? Might try telling that to the HPV community.It seems to me that the iBike might be a good PM for this "experiment" since using a regular PM doesn't allow one to know that the headwinds are the same for the two rides. The problem is, of course, we still don't know if they controlled for headwinds so it probably would have been better if they used a regular PM and the iBike meter so they could know the bike power and the headwinds were the same for the two runs. It would be even better, of course, to have done this in a wind tunnel, where the drag difference could be better quantitated because power there doesn't matter. I wouldn't claim their testing as being very rigorous but, they did what they did and, it seems, didn't try to lie about it, publishing their results. You may not like it but it hardly seems worth such derision for a product aimed at the commuter market, trying to make it easier for people to ride into headwinds. And, it hardly seems appropriate for this thread where there is actually some real science that could be discussed specific to the product in question.

Frank, I did the analysis of their claims using the data they actually provided on their website in the public domain. It doesn't add up. Badly.

Clearly you haven't read them, nor what I said either:

I did not say that the fairings would not work to improve aerodynamics.

What I said is that the scope of improvement claimed from the fairings was implausible. You don't put a couple of small fairings on a bike and drop CdA by half. The rider accounts for 70-80% of the total drag.

If you genuinely think the ibike Newton is suitable for this analysis, then you are deluded.

 

[acoggan]

Well there is a bit of a catch, it requires total immersion for 6-9 months, non use of any device that could objectively track actual changes, and you need to be clinically dead before starting.

Dead, or just brain-dead?

 

[FrankDay]

Frank, I did the analysis of their claims using the data they actually provided on their website in the public domain. It doesn't add up. Badly.

Perhaps you could explain how you did the analysis. It appears to me that you might have gone to analytic cycling and seen what change in frontal area resulted in a 10% increase in speed using their default data. A 50% reduction in frontal area (or CdA) results in about a 10% increase in speed. Unfortunately, their default data involves a 3% slope. Do the calculation on level ground and a 50% reduction results in a 25% increase in speed. While I don't like their test protocol it appears your analysis is hardly any better. Could you clarify?

Clearly you haven't read them, nor what I said either:

I did not say that the fairings would not work to improve aerodynamics.

The original post called them a gimmick and referred to "baseless" claims. Your follow-up did not clarify that you were only concerned with the amount of the improvement seen from such a change.

What I said is that the scope of improvement claimed from the fairings was implausible. You don't put a couple of small fairings on a bike and drop CdA by half. The rider accounts for 70-80% of the total drag.

As noted above, could you clarify how you calculated the need to reduce CdA by half? I find your analysis implausible.

If you genuinely think the ibike Newton is suitable for this analysis, then you are deluded.

. Well, if you think a regular power meter alone would be suitable then you are deluded. If one wants to really do this test correctly then one must account for both bike power and wind speed. Their testing protocol was indeed flawed but no more so than your analysis of their results, or so it seems.

Edit: one more thing, it looks like their test involved a bike with 36 spoke wheels and we might expect the results to compare to changing to two aero wheels. In that case, I think their "average" improvement of 7% is in the ballpark of what one might expect from such a change. The problem is that "headwinds" complicate the analysis and I would think would amplify the improvement normally seen from reducing the spoke drag.

 

[acoggan]

if you think a regular power meter alone would be suitable then you are deluded.

Guess I'm deluded:

http://www.trainingandracingwithapowermeter.com/2010/10/challenge-to-cycling-aerodynamicists.html

If one wants to really do this test correctly then one must account for both bike power and wind speed.

When it comes to field testing, wind is indeed thine enemy. Unfortunately, though, the iBike's wind sensor really isn't up to the task at hand, such that owning one really doesn't help matters any.

 

[FrankDay]

Guess I'm deluded:

http://www.trainingandracingwithapowermeter.com/2010/10/challenge-to-cycling-aerodynamicists.html

What does that have to do with the test in question? their test was done in a strong headwind. To know that the speed increases they saw were valid not only would they need to know that the power was the same but the wind was the same (direction and velocity) assuming the riders position was the same. All you showed is that a power meter can be used to accurately detect drag in dead air. If you think their test could have been accurately done using just a PM you are deluded. But, since you have admitted to it I guess I am being redundant.

When it comes to field testing, wind is indeed thine enemy. Unfortunately, though, the iBike's wind sensor really isn't up to the task at hand, such that owning one really doesn't help matters any.

Well, the iBike's wind sensor is, at least, a wind sensor such that it was an attempt to control for wind speed. It was a poorly conceived study if one was looking for accuracy but you guys, apparently, would have done no better. You would have simply made other errors.

Do you agree with Alex Simmons analysis?

 

[acoggan]

What does that have to do with the test in question? their test was done in a strong headwind.

First, I don't know why you're blaming me for the fact that they conducted a poor experiment.

Second, I was addressing your claim that you couldn't easily test their claim using what iBike calls a "direct force power meter". The answer is, of course you can, but only if you pay sufficient attention to important experimental details.

the iBike's wind sensor is, at least, a wind sensor

Technically, it's a pressure sensor, but that's picking nits - the real problem with it, at least for this application, is that it is overly-sensitive to off-axis winds. Thus, while it might do a half-way decent job of measuring relative wind speed under low wind (and hence low yaw) conditions, on windy days having the extra data doesn't really improve the accuracy or precision of the CdA measurements.

And yes, I have evaluated an iBike for this purpose...

 

[FrankDay]

First, I don't know why you're blaming me for the fact that they conducted a poor experiment.

Second, I was addressing your claim that you couldn't easily test their claim using what iBike calls a "direct force power meter". The answer is, of course you can, but only if you pay sufficient attention to important experimental details.

The question wasn't whether one could measure if there was a drag difference? The question was could you reproduce their experiment, looking at high headwinds, using just a power meter. The answer is, of course, NO! But you come here and obfuscate, as usual, and you didn't answer the question regarding Alex Simmons Analysis. Do you agree with him that their results (a 7-14% increase in speed in high headwind conditions) require a 50% reduction in CdA so are "implausible?"

Technically, it's a pressure sensor, but that's picking nits

Nits indeed. see pitot tube. LOL

- the real problem with it, at least for this application, is that it is overly-sensitive to off-axis winds.

Do you know their winds were off axis?

Thus, while it might do a half-way decent job of measuring relative wind speed under low wind (and hence low yaw) conditions, on windy days having the extra data doesn't really improve the accuracy or precision of the CdA measurements.

But, of course, not having wind data also doesn't improve the accuracy or precision of the CdA measurements, does it?

And yes, I have evaluated an iBike for this purpose...

Cool. Lots of good it did you in answering this question. Again, what did you think of A Simmons analysis. Do you agree with it?

 

[acoggan]

(snip)

Obfuscation is deliberately confusing test protocols with claims...LOL, phooey, and all that.

 

[FrankDay]

Obfuscation is deliberately confusing test protocols with claims...LOL, phooey, and all that.

LOL, Obfuscation.

Having trouble answering the questions, again.

Again, what did you think of A. Simmons evaluation of the results. Do you agree with it?

Do you really still think you can do a reasonable evaluation of drag in strong headwinds (which is what the paper in question was trying to do) only knowing the bicycle power?

 

[Alex Simmons/RST]

Frank

This is what I said, and it was in response to you:

http://forum.cyclingnews.com/showpost.php?p=1548350&postcount=558

If you want to make stuff up, well I can't help that.

As for the analysis, I did it for more than one scenario and didn't bother to note those down as I was just doing a quick BS test, but the example that was originally linked here, I'll post my numbers below for everyone to see.

I don't use analytic cycling, I don't need to since I have the models on my own computers. I use the Martin et al model, since that's been well verified. But you could use analytic cycling if you like.

The scenario posted was a novice rider in a 22.9mph headwind who attained a 22.2% speed improvement because of the addition of the fairings. Here is Nullwind's pdf report taken directly from the link previously posted.
http://nullwinds.com/StrongWindGM.pdf

I do note this statement from their own report:

While the rider attempted to maintain a similar level of effort with similar breathing, the heart rate measured was slightly higher (about 10 percent) on the second run with the fairings. However, it seems likely that this could be in part due to tiredness of the rider. Still, the gains are dramatic.

And funny enough, when you examine even the (quite possibly suspect) ibike power data they show, the reported power for the fairing bike run was 36% higher than the run on the equivalent non faired bike.

How are we expected to take such claims of aero improvement seriously?


But let's ignore those anomalies and just look at the numbers they actually provide.

Wind: Headwind of 23mph (10.3 m/s)
At level of rider? Maybe in reality it's half that* but let's assume for the moment it really was 23mph against the rider.

Power: 149.4W
They reported 149.4W for the rider on the non-faired bike. Note that the faired bike run reported average power of 202.9W (+53.5W, +35.8%). I'll do the numbers to see what reduction in CdA is required to attain the claimed speed improvement at the same power.

CdA: 0.372m^2 (non-faired bike)
They report a CdA of 0.372m^2 for the non-faired bike. I've no reason to question whether that's correct or not, it's a plausible number for a novice on a standard steel framed road bike in the drops. We are of course testing relative changes due to the fairing in any case.

Crr: 0.0054
They report a Crr of 0.0054 and again I've no reason to suspect that's wildly wrong as it sounds plausible for road bike on a road. I will keep that constant (as they did).

Gradient: +0.5%
This one is tricky as they report a different slope for the same piece of road used for the test. +0.29% non-faired test and +0.55% for the faired bike test. Again if that doesn't make you wonder about their numbers...
Keep in mind that an ibike relies on gradient slope data for it's power calculations.
So for the sake of sensible comparison I'll assume the actual road didn't magically change slope between runs and use +0.5%.

Mass: 188lbs (85.3kg)
They report 188lbs. I don't know if that's bike + rider or just rider but I'll assume that's total mass.

Air density: 1.108kg/m^3
They report 70F (21.1C) and 1020HpA for their calculations, no humidity reported but weather report they provided shows that to be between ~30% and 50%. I'll use 40%. They don't report elevation but Fox Airfield (right next to the road used) is reported to be at 2351 feet (717 metres).
That gives an air density of 1.108kg/m^3.

Speed:
So with those power and other assumptions, you'd expect a rider to attain a speed of 3.23m/s = 11.62 km/h = 7.22 mph.

They reported an average speed on the non-faired bike run of 7.2mph.


OK, so what CdA would be required, all else the same, to attain a speed increase of 22.2% (i.e. from 7.22 to 8.82 mph):

0.261m^2.
That's a reduction in CdA of 0.11m^2, or a 30%!

That's the equivalent of removing the air drag of the entire bike and quite probably some of the rider!


Now here's the kicker:
What do they report the change in CdA to have been?

They report a CdA for the faired bike run of 0.369m^2
That's a drop of 0.003m^2 or just 0.8%


Sorry Frank, I'm not buying it.

It's a great lesson in why using speed changes is a really crappy way to claim a performance improvement for a device. In this case they test subject simply rode harder on the faired bike run.


* Wind at rider level is not 100% of reported wind due to the atmospheric boundary layer wind velocity profile, which goes from 0% to 100% of reported wind velocity from on the ground to the height wind measurements are standardised at, usually 10 metres above ground. Note it's a non-linear profile.

 

[Alex Simmons/RST]

Here, I did a blog post on it, using a slightly more detailed look at the data.
http://alex-cycle.blogspot.com.au/2014/08/the-null-hypothesis.html

 

[CoachFergie]

It's no wonder the rider went faster on the faired bike.
They simply rode harder.
http://alex-cycle.blogspot.com.au/2014/08/the-null-hypothesis.html

There we have it, simple science!

Well done Alex, awesome analysis of the data provided.

An easy challenge to powercrankers is to use a Powertap wheel to learn three things...

Putting independent cranks on does not increase power, as Frank has said, it decreases it. On normal cranks, one just pedals harder to increase power. Of course the harder one pedals the shorter the duration one can sustain. This is why we train to ride harder for longer.

Using independent cranks for a short period of 5-10 weeks, as Frank has said this is not enough time to see any benefits. No studies of training with a independent crank have shown a benefit beyond the noise of measurement using various physiological measures and the only objective performance measure which is power.

Power is an excellent measures of changes in performance. So sensitive to changes that both studies led by Bertucci and Lim found that power meters could pick up changes in performance between 60psi and 120psi (Lim) and smooth and knobbled (Bertucci) tyres. And a huge variety of training studies that showed improvements in performance of up to 100% from a training stimulus of as little as 12-18mins of short interval training over a 2 week period (Gibala and other authors). But no improvements in cycling power compared to a control group from ANY independent crank study.

Use your independent cranks for 6-9 months of immersion training, assuming you don't want to race in that time to see, as Frank himself has said, how going back to normal cranks for competition harms your performance.

It is hardly surprising that in 13 years of independent cranking that no one has come close to providing worthwhile evidence of any of Franks claims. Like Nullwind why would you waste your time?

 

[FrankDay]

Frank

This is what I said, and it was in response to you:

http://forum.cyclingnews.com/showpost.php?p=1548350&postcount=558

If you want to make stuff up, well I can't help that.

Make stuff up? Here is what you said

More to the point though are the scope of performance improvement they claim which, like yours, are implausible.

e.g. they claimed one novice level rider gained a 20% speed improvement while riding into strong headwinds at same power*.

If that were true, it would require these fairing to achieve the remarkable result of halving the total bike and rider CdA (coefficient of drag).

but, if we go to the original link I think we can see that this is what they claimed

1. Test Summary
The following plot of the best available data taken on November 3, 2013, indicates that the use of our Upper Wheel Fairings on a typical road bike with a strong rider under severe headwind conditions yields gains in average speed of at least seven percent. At times, gains in excess of 10 percent were recorded. …

It is my conclusion that when riding into a headwind with the addition of the Null Winds Technology Upper Wheel Fairings, any bicycle will be noticeably faster at any speed!"

Jason Shutz
November 15, 2013

3. Implications
The results confirm that the use of our Upper Wheel Fairings can significantly increase headwind penetration speeds of a strong rider under severe headwinds. Gains exceeding seven percent are likely, with the potential gains in excess of 10 percent.

Now I don't see anywhere that they claimed a 20% improvement from using their device, even though on some runs they may have seen such speed improvements.

As for the analysis, I did it for more than one scenario and didn't bother to note those down as I was just doing a quick BS test, but the example that was originally linked here, I'll post my numbers below for everyone to see.

So, you went into this with a bias that the numbers were BS and with the intent to prove it. Is that correct?

I don't use analytic cycling, I don't need to since I have the models on my own computers. I use the Martin et al model, since that's been well verified. But you could use analytic cycling if you like.

How does your model deal with headwinds?

The scenario posted was a novice rider in a 22.9mph headwind who attained a 22.2% speed improvement because of the addition of the fairings. Here is Nullwind's pdf report taken directly from the link previously posted.
http://nullwinds.com/StrongWindGM.pdf

But, the original link seems to have nothing to do with the scenario you examined. They ignored that data (probably thinking it an outlier) and only included data for headwinds above 25 mph

I do note this statement from their own report:



And funny enough, when you examine even the (quite possibly suspect) ibike power data they show, the reported power for the fairing bike run was 36% higher than the run on the equivalent non faired bike.

How are we expected to take such claims of aero improvement seriously?

Because, 7% improvement is in line with what one might expect from an effective wheel fairing.
http://www.sheldonbrown.com/rinard/aero/aerodynamics.htm
http://cyclingtips.com.au/2010/04/biggest-bang-for-your-buck-in-time-trial-equipment/

But let's ignore those anomalies and just look at the numbers they actually provide.

Wind: Headwind of 23mph (10.3 m/s)
At level of rider? Maybe in reality it's half that* but let's assume for the moment it really was 23mph against the rider.

Power: 149.4W
They reported 149.4W for the rider on the non-faired bike. Note that the faired bike run reported average power of 202.9W (+53.5W, +35.8%). I'll do the numbers to see what reduction in CdA is required to attain the claimed speed improvement at the same power.

CdA: 0.372m^2 (non-faired bike)
They report a CdA of 0.372m^2 for the non-faired bike. I've no reason to question whether that's correct or not, it's a plausible number for a novice on a standard steel framed road bike in the drops. We are of course testing relative changes due to the fairing in any case.

Crr: 0.0054
They report a Crr of 0.0054 and again I've no reason to suspect that's wildly wrong as it sounds plausible for road bike on a road. I will keep that constant (as they did).

Gradient: +0.5%
This one is tricky as they report a different slope for the same piece of road used for the test. +0.29% non-faired test and +0.55% for the faired bike test. Again if that doesn't make you wonder about their numbers...
Keep in mind that an ibike relies on gradient slope data for it's power calculations.
So for the sake of sensible comparison I'll assume the actual road didn't magically change slope between runs and use +0.5%.

Mass: 188lbs (85.3kg)
They report 188lbs. I don't know if that's bike + rider or just rider but I'll assume that's total mass.

Air density: 1.108kg/m^3
They report 70F (21.1C) and 1020HpA for their calculations, no humidity reported but weather report they provided shows that to be between ~30% and 50%. I'll use 40%. They don't report elevation but Fox Airfield (right next to the road used) is reported to be at 2351 feet (717 metres).
That gives an air density of 1.108kg/m^3.

Speed:
So with those power and other assumptions, you'd expect a rider to attain a speed of 3.23m/s = 11.62 km/h = 7.22 mph.

They reported an average speed on the non-faired bike run of 7.2mph.


OK, so what CdA would be required, all else the same, to attain a speed increase of 22.2% (i.e. from 7.22 to 8.82 mph):

0.261m^2.
That's a reduction in CdA of 0.11m^2, or a 30%!

That's the equivalent of removing the air drag of the entire bike and quite probably some of the rider!


Now here's the kicker:
What do they report the change in CdA to have been?

They report a CdA for the faired bike run of 0.369m^2
That's a drop of 0.003m^2 or just 0.8%


Sorry Frank, I'm not buying it.

It's a great lesson in why using speed changes is a really crappy way to claim a performance improvement for a device. In this case they test subject simply rode harder on the faired bike run.


* Wind at rider level is not 100% of reported wind due to the atmospheric boundary layer wind velocity profile, which goes from 0% to 100% of reported wind velocity from on the ground to the height wind measurements are standardised at, usually 10 metres above ground. Note it's a non-linear profile.

Look, we both know that from a scientific perspective their protocol sucked. But, their final claim, a 7-10% speed improvement in severe headwinds, is plausible as it is close to what one might expect going from 36 spoke box rims to aero wheels. But, you instead choose to examine data that showed higher speed increases, that also involved power increases, pretended that there was no power increase, and then stated that their claims would require a 50% reduction in CdA!. So, in other words, you lied to make them look bad. It would have been easy enough to criticize what they did without deliberately misrepresenting the data. The fact you did this is a serious blow to your credibility, at least to those who pay attention to such stuff.

Further, it is really stupid that we are even discussing this issue on this thread. Apparently it was posted thinking that somehow what these people did would reflect on me by association. Exactly how does that work? You guys must be getting desperate to try to make some points. Another fail, I am afraid. LOL

 

[Alex Simmons/RST]

Make stuff up? Here is what you saidbut, if we go to the original link I think we can see that this is what they claimedNow I don't see anywhere that they claimed a 20% improvement from using their device, even though on some runs they may have seen such speed improvements.So, you went into this with a bias that the numbers were BS and with the intent to prove it. Is that correct?How does your model deal with headwinds?But, the original link seems to have nothing to do with the scenario you examined. They ignored that data (probably thinking it an outlier) and only included data for headwinds above 25 mph

Because, 7% improvement is in line with what one might expect from an effective wheel fairing.
http://www.sheldonbrown.com/rinard/aero/aerodynamics.htm
http://cyclingtips.com.au/2010/04/biggest-bang-for-your-buck-in-time-trial-equipment/
Look, we both know that from a scientific perspective their protocol sucked. But, their final claim, a 7-10% speed improvement in severe headwinds, is plausible as it is close to what one might expect going from 36 spoke box rims to aero wheels. But, you instead choose to examine data that showed higher speed increases, that also involved power increases, pretended that there was no power increase, and then stated that their claims would require a 50% reduction in CdA!. So, in other words, you lied to make them look bad. It would have been easy enough to criticize what they did without deliberately misrepresenting the data. The fact you did this is a serious blow to your credibility, at least to those who pay attention to such stuff.

Further, it is really stupid that we are even discussing this issue on this thread. Apparently it was posted thinking that somehow what these people did would reflect on me by association. Exactly how does that work? You guys must be getting desperate to try to make some points. Another fail, I am afraid. LOL

Read the blog post.

But in case you missed it, here is what they say:

NOVICE RIDER February 9, 2014
1. Test Summary
The best available data taken on February 9, 2014, indicates that the use of our Upper Wheel Fairings on a typical road bike with a novice rider under strong headwind conditions yields gains in average speed exceeding 20 percent (22.2 percent was recorded). (The full report is available for download.) Power measuring tests in severe headwinds were conducted on identical multi-speed road bikes configured with and without wheel fairings. A novice cyclist was the rider. Data was recorded using an i-bike Newton power meter.

2. Implications The results confirm that the use of our Upper Wheel Fairings can dramatically increase headwind penetration speeds of a novice rider under strong headwind conditions. Gains exceeding 20 percent are possible.

That's their claim. Verbatim Quote.

IOW Use our fairings in strong headwinds and you can get a speed boost of more than 20%.

What they failed to point out in their claim was the rider doing the runs with the bike fairing rode with power 36% higher than the non-faired bike run. They also reported their HR was 10% higher.

So they may very well have ridden faster, but the reason was because the rider rode harder. It had very little, if anything, to do with the fairings, which based on their own data showed a less than 1% reduction in CdA.

 

[FrankDay]

Read the blog post.

But in case you missed it, here is what they say:

2. Implications The results confirm that the use of our Upper Wheel Fairings can dramatically increase headwind penetration speeds of a novice rider under strong headwind conditions. Gains exceeding 20 percent are possible.

That's their claim. Verbatim Quote.

IOW Use our fairings in strong headwinds and you can get a speed boost of more than 20%.

What they failed to point out in their claim was the rider doing the runs with the bike fairing rode with power 36% higher than the non-faired bike run. They also reported their HR was 10% higher.

So they may very well have ridden faster, but the reason was because the rider rode harder. It had very little, if anything, to do with the fairings, which based on their own data showed a less than 1% reduction in CdA.

LOL. Let me point out a few things.

1. The original post about wheel fairings never belonged in this thread about PowerCranks.
2. The original link never made this claim, this came from some subsequent testing.
3. Let's change their test and report to something like this

2. Implications The results confirm that the use of a power meter can dramatically increase headwind penetration speeds of a novice rider under strong headwind conditions. Gains exceeding 20 percent are possible when combined with aerodynamic wheels. We believe this is because a power meter allows the rider to better pace themselves and achieve a higher power and when combined with the aerodynamic effects of aero wheels the results can be dramatic.

You guys would be all over this as being evidence that power meters help riders ride faster. Fergie would have posted this in the PM thread to help PM's look good rather than in this thread to make PC's look bad even though the "science" would have been equivalently bad in both instances. I doubt you would have criticized what they did then because it would have met with your expectation.

4. It doesn't appear the people doing this test were trying to hide the fact the rider rode at a higher power and effort. All they said was that the rider was able to increase his speed with the fairings with that run. You were able to find out the "truth" because they, apparently, included it. The really crazy thing about this is I can't believe a single person who visits this thread would be interested in this fairing (even though there should be a speed benefit to using it, only the amount of benefit remains in question) since they are illegal for racing and "making things easier" during training offers no advantage that I have ever heard of.

5. Just because you find something implausible is not evidence that the claim is not possible or true? This is a thread about PowerCranks. If you have some real evidence that says our claim is not true why don't you present it? It not, then, stop making yourself look bad by trying to associate me with these fairing people.

 

[CoachFergie]

So they may very well have ridden faster, but the reason was because the rider rode harder. It had very little, if anything, to do with the fairings, which based on their own data showed a less than 1% reduction in CdA.

Nice work Alex, at least Nullwinds tried to find some data to support their claims. Just a pity it was all wrong. Still better than making claims and providing no decent evidence to support them. Which is why this discussion fits nicely in this thread

 

[Alex Simmons/RST]

Nice work Alex, at least Nullwinds tried to find some data to support their claims. Just a pity it was all wrong. Still better than making claims and providing no decent evidence to support them. Which is why this discussion fits nicely in this thread

That seems to have gone over Frank's head, who thinks it's everyone else's fault his implausible claims have not been supported by any credible evidence so far.

Indeed Frank hasn't managed to refute the null hypothesis either (i.e. that any performance changes he does report have nothing to do with his cranks). This is a basic evidentiary requirement before then moving on to test the alternative hypothesis, i.e. use of the cranks significantly improves performance, e.g. by providing an average of 40% more power.

My point was that Nullwinds hadn't refuted the null hypothesis, and neither has Frank.

 

[Alex Simmons/RST]

LOL. Let me point out a few things.

1. The original post about wheel fairings never belonged in this thread about PowerCranks.
2. The original link never made this claim, this came from some subsequent testing.
3. Let's change their test and report to something like this
You guys would be all over this as being evidence that power meters help riders ride faster. Fergie would have posted this in the PM thread to help PM's look good rather than in this thread to make PC's look bad even though the "science" would have been equivalently bad in both instances. I doubt you would have criticized what they did then because it would have met with your expectation.

4. It doesn't appear the people doing this test were trying to hide the fact the rider rode at a higher power and effort. All they said was that the rider was able to increase his speed with the fairings with that run. You were able to find out the "truth" because they, apparently, included it. The really crazy thing about this is I can't believe a single person who visits this thread would be interested in this fairing (even though there should be a speed benefit to using it, only the amount of benefit remains in question) since they are illegal for racing and "making things easier" during training offers no advantage that I have ever heard of.

5. Just because you find something implausible is not evidence that the claim is not possible or true? This is a thread about PowerCranks. If you have some real evidence that says our claim is not true why don't you present it? It not, then, stop making yourself look bad by trying to associate me with these fairing people.

1. perhaps, it was more as another similar example of implausible claims of substantial performance improvement

2. the link posted went straight to the page listed showing the strong headwind tests, including the additional supporting information.

3. Strawman Frank. No one has ever made such claims about a power meter. They may have used a power meter to demonstrate whether or not a claim of benefit was valid.

4. Yet it didn't stop them claiming the speed gain was a result of using their product:

2. Implications The results confirm that the use of our Upper Wheel Fairings can dramatically increase headwind penetration speeds of a novice rider under strong headwind conditions. Gains exceeding 20 percent are possible.

When they should have concluded:
Our tests failed to demonstrate Upper Wheel Fairings are responsible for the increase headwind penetration speeds of a novice rider under strong headwind conditions. The test data indicate the speed increase was due to the rider's increased power output.

5. How about you refute the null hypothesis first Frank? The burden of proof is with those that make the claims of impact from use of a product.

 

[FrankDay]

1. perhaps, it was more as another similar example of implausible claims of substantial performance improvement

2. the link posted went straight to the page listed showing the strong headwind tests, including the additional supporting information.

3. Strawman Frank. No one has ever made such claims about a power meter. They may have used a power meter to demonstrate whether or not a claim of benefit was valid.

Sure they have "made such claims regarding power meters. A few examples:
What Amazon says in trying to sell the book Training and Racing with a Power Meter:

In only a few short years, power meters have become an essential training tool for amateur and pro cyclists and triathletes. The first edition of Training and Racing with a Power Meter was largely responsible for popularizing what was once an arcane technology understood by only a few elite coaches and trainers. Now the updated and revised second edition provides significant updates on technology, software tools, training protocols, and workouts, making the benefits of power-based training available to everyone. The new edition also includes specific information for triathletes—the fastest-growing segment in endurance sports—including a complete triathlon training plan. Other significant updates include reviews of the latest hardware, refinements and additions to training plans, additional case studies, more on monitoring fitness and chronic training loads, and revised and clarified artwork, charts and tables throughout. Training and Racing with a Power Meter, 2nd Ed., will continue to be the definitive guide to the most important training tool ever developed for endurance sports.

There is zero scientific support for the highlighted segments. At least I am glad to see Coggan supports the use of "case studies" (anecdotes) when it suits his purpose.

Or, this is what Joe Friel says:

So why should you get a power meter? The short answer is that you simply are more likely to achieve your race goals by training—and racing—with a power meter than without. It is the most affective tool you can get to go faster on a bike.

Again, zero scientific support for the highlighted statement.

Or this:

Training with a power meter is quickly becoming the key training tool to take your cycling fitness to a whole new level! Using a power meter enables you to measure you effort through watts, which leads to better quality training sessions, improved fitness, as well as a better paced race effort come race day. Start training with power and enter a whole new level of performance!

Zero scientific support.

Or this:

Training with a Powermeter; the most accurate and effective training tool.
…For return on investment a powermeter gets results time and time again over and above the short term gains of an expensive bike.

It provides a clear edge over the competition.

Zero scientific support for those statements.

People have just stopped making such claims here because they know such claims have no scientific basis and they will be asked (by me) to support them with facts. In fact, attempts to scientifically demonstrate a benefit to using a power meter (including one done by our own coachfergie) have never shown even any hope of there being a benefit.

4. Yet it didn't stop them claiming the speed gain was a result of using their product:

Your point? Are you trying to say there should be no speed benefit to using a fairing over the wheels? Your objection is to the size of the improvement noted. I would agree that is most likely in error due to a poor test design. But, they weren't trying to do a scientific study. What they did qualifies as an anecdotal report, which can be good or not so good. In this case it is probably not so good but it doesn't mean that the product probably does nothing. Fairings are not new technology and adding a fairing to a bike would be expected to increase the speed for any given power, headwind or not. Only question is how much. And, further, it doesn't really matter, as no one here would by one anyhow, regardless of how good it was, because it is illegal for racing.

When they should have concluded:
Our tests failed to demonstrate Upper Wheel Fairings are responsible for the increase headwind penetration speeds of a novice rider under strong headwind conditions. The test data indicate the speed increase was due to the rider's increased power output.

I disagree. What they should have said, if they were doing this as a scientific project was: "Fairings should improve speed on a bicycle but it is very difficult to control for all the variables to measure this effect on an open road. Our data suggests there is a positive effect from this device but we are unable to accurately quantify it."

5. How about you refute the null hypothesis first Frank? The burden of proof is with those that make the claims of impact from use of a product.

Because of the potential for bias it is impossible for me to do a good scientific test "proving" the benefits on my own product. We have done our own little study that suggested an improvement that users might expect and subsequent reports from many many users support that figure. Further, there have been scientific studies that do support the null hypthesis, the best one being Dixon (see post #4 of this thread):

PowerCranks are cycling cranks that are independent of each other, requiring force application throughout the pedal stroke, theoretically increasing muscle recruitment and stimulus in the legs. This study examined the physiological adaptations to PowerCranks, and the time course of responses in maximal and submaximal cycling performance. Eight Trained cyclists (35.1 ± 6.8 yr) participated in 6 wks of 100% immersion training using solely PowerCranks, consisting of ~8 h/wk of aerobic and anaerobic (~80:20) cycling training. A continuous incremental cycling test to exhaustion (50 W increase every 2 min) was performed prior to and following the training program using normal cranks. In addition, 10 min of submaximal cycling (70% of VO2max wattage) were performed with both normal cranks and PowerCranks at an approximate cadence of 85 rpm, pre and post training. VO2max increased 15.6% (58.1 ± 5.8 to 67.3 ± 6.6, P=0.013). Maximum power increased 11.6% (316.7 ± 25.8 to 358.3 ± 20.4, P=0.011) following PowerCranks training. In summary, our data suggest that PowerCranks increased maximal aerobic capacity and power in trained cyclists.

The fact that there isn't a study lasting 6-9 months using an immersion training protocol showing 40% improvement does not suggest that the claim is "implausible" when there are studies such as Dixon available. You simply choose to ignore the data you don't like so you can continue to keep your head in the sand and do what you are used to or, even worse, admit that you might be wrong.

 

[Alex Simmons/RST]

The fact that there isn't a study lasting 6-9 months using an immersion training protocol showing 40% improvement does not suggest that the claim is "implausible" when there are studies such as Dixon available. You simply choose to ignore the data you don't like so you can continue to keep your head in the sand and do what you are used to or, even worse, admit that you might be wrong.

All it shows is just how deluded you are.

As for Dixon, what was the control group's response to the same training protocol performed on normal cranks?

Ah, that's right, there wasn't one....

So was it the cranks, or the training, or perhaps even some form of uncontrolled bias that caused an improvement in reported VO2max and power?*

If you think this study refutes the null hypothesis, you are, well, deluded.



* That was a rhetorical question by the way.

 

[FrankDay]

All it shows is just how deluded you are.

As for Dixon, what was the control group's response to the same training protocol performed on normal cranks?

Ah, that's right, there wasn't one....

Ugh, there was a control group otherwise they would not have been able to do the statistics to calculate those P values. Just because YOU do not understand the study design does not invalidate it. Study was good enough to pass muster with the CSEP. So, my friend, there is your null hypothesis study that demonstrates they actually do something.

So was it the cranks, or the training, or perhaps even some form of uncontrolled bias that caused an improvement in reported VO2max and power?*

If you think this study refutes the null hypothesis, you are, well, deluded.



* That was a rhetorical question by the way.

it doesn't matter because we don't claim that all of the improvement come from the PowerCranks. I presume there is some training effect benefit in most of our non-elite users. But it is unlikely that all the benefit is training effect or you wouldn't find the claim so implausible. My guess is that more than half the benefit that most see is due to the PC's but I have no way to separate out the effect. Does it matter to you if you are the one seeing a benefit that you were previously unable to obtain?

 

[Alex Simmons/RST]

Ugh, there was a control group otherwise they would not have been able to do the statistics to calculate those P values.

Woah - what? The P values are simply from comparison of before and after training results with the null hypothesis is that training does not work.

They do not tell us anything about the role Powercranks play. To get a p value for Powercrank's influence on outcomes you need to compare them with a control group on regular cranks.

Just because YOU do not understand the study design does not invalidate it. Study was good enough to pass muster with the CSEP. So, my friend, there is your null hypothesis study that demonstrates they actually do something. it doesn't matter because we don't claim that all of the improvement come from the PowerCranks.

But since you claim there was a control group, then please do share the full study so we can review the data properly.

Oh wait, it never got published. I wonder why? Maybe the CSEP wised up.

OK, then post the control group data.

Oh wait, you can't give us the control group data can you Frank? That's because there was no control group.

Frank, you know this, it's been pointed out to you time and again for the past 8 years and yet you still lie about it. Please stop.

I presume there is some training effect benefit in most of our non-elite users. But it is unlikely that all the benefit is training effect or you wouldn't find the claim so implausible. My guess is that more than half the benefit that most see is due to the PC's but I have no way to separate out the effect. Does it matter to you if you are the one seeing a benefit that you were previously unable to obtain?

You can't presume anything of the sort from this study. To do so would be delusional.

It's the same logical fallacy as follows:
The team gained an average 20% improvement in power by training on my brand of blue coloured bikes. I presume part of the reason they gained power was because of the bike colour.

 

[Alex Simmons/RST]

Here's a study over a similar time frame that did have a control group. And got published.

http://journals.humankinetics.com/i...ng-with-uncoupled-cranks-in-trained-cyclists-

What do we see? No difference when compared with a control group using normal cranks.

Mind you, it's all deja vu given this was posted on page one of this thread.

 

[CoachFergie]

Woah - what? The P values are simply from comparison of before and after training results with the null hypothesis is that training does not work.

That has to be the stupidest thing I have seen Frank write.