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Power Data Estimates for the climbing stages

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Alex Simmons/RST said:
>10% more power than next non-Sky rider?

Quintana finished 29 seconds down on a climb that took nearly an hour. That's less than 1% difference in speed. That is most definitely not going to result in a more than 10% difference in power.

I can't see that linked website, so can't really comment or not if that's what they actually claim, but if it is, it's nonsense.
It's about Ax-3, and not Ventoux I believe.
 
Jun 18, 2009
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Alex Simmons/RST said:
>10% more power than next non-Sky rider?

Quintana finished 29 seconds down on a climb that took nearly an hour. That's less than 1% difference in speed. That is most definitely not going to result in a more than 10% difference in power.

I can't see that linked website, so can't really comment or not if that's what they actually claim, but if it is, it's nonsense.

I can't open the link. I'm guessing the Clinic broke Ferrari's web page, so pure speculation: he's taking power over the last section of the climb, like the last 5K or something (in which case, that's misleading as well since Quintana obviously put in a bigger effort to get the gap before that). Quintana was in the group from 15K to go, so yeah--no way his w/kg was 10% more than his over the last 15K. Given the spread over Contador et. al. though, I'm not sure my conclusions have changed...
 
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Let's re-read the quoted text, shall we?

Ferrari said:
Now, assuming the aerodynamic efficiency to be equal for all riders (something that IS NOT...), considering the square speeds, the difference in power would be represented as follows:

Froome: 54.0 Km / h - 2916 (v2)
Porte: 52.3 - 2738, -6.5&#37]

i.e. the TT.

Ferrari said:
In the last 5 km of the climb towards Aix 3 Domaines, from the moment of Froome's attack, the differences were smaller (but still very significant):

Porte: -5.5%
Valverde: -7.5%
Mollema: -7.6%
Contador: -11.5%
Quintana: -11.5%

i.e. the climb to Ax3D.
 
Eshnar said:
It was referring to the ITT, not the Ventoux stage.
edit: see post #1881

really?

Well that's an even greater level of nonsense.

seriously, do these people have any effing clue about how variable rider's aerodynamics are, let alone the variable wind conditions over the course of the ITT?

making W or W/kg comparisons from climb data is one thing, but from an ITT, well that's just fairyland.
 
Eshnar said:
It was referring to the ITT, not the Ventoux stage.
edit: see post #1881
The important part of that post then is "aerodynamic efficiency is NOT the same" between different individuals. It's not even a matter of determining the CdA in the aero position. It also comes down to how long the rider stays in that position on the ride. Knowing a given rider's CdA is completely useless to the power calculation if you don't know exactly how long each rider held their aero position. Seriously, trying to calculate how much more or less power a rider is producing based on velocity alone is a joke.

edit: for the cimbing w/kg you MUST know the exact rider weight, otherwise the error in that alone could be 5-10%.

In this thread you've got two people (acoggan and Alex Simmons), who combined probably have more knowledge and experience at interpreting these relationships (ie: resistance vs propulsive variables in cycling) than the entire forum combined, and yet many people still want to argue that they are wrong and you CAN determine power output with sufficient precision to then go and claim rider A produced 10% more power than rider B, or that "X" watts or w/kg is humanly impossible which therefore is "proof" of doping.

It's all b#llsh!t. All you can do is look at large sample sizes and make inferences based on trends in the numbers.
 
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karlboss said:
Forgive me for assuming the info on the website no matter when it was posted was still relevant.

You misunderstand, so here's another hint: compare the equations they provide in that relatively recent post to our published model from 1998.
 
Krebs cycle said:
The important part of that post then is "aerodynamic efficiency is NOT the same" between different individuals.

and that's exactly where that post should have stopped, because after that the numbers quoted are just nonsense.


People are looking for a dopeometer, I get that. But FFS, use something that makes sense. All that quoting these nonsense wattage guesses does is weaken people's arguments.
 
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Krebs cycle said:
edit: for the cimbing w/kg you MUST know the exact rider weight, otherwise the error in that alone could be 5-10%.

Even when w is expressed as w/kg? learn something new every day...

I do agree that the general extrapolations based on TT times is ridiculous though. The way the post was originally worded I thought it was based on the Ventoux climb. About the only comparison you could probably make is compared to Contador. His position is solid, he's obviously able to hold the position as witnessed by his TT pedigree, his equipment is equal or better to Froome's stuff and most importantly he went off around the same time.
 
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Krebs cycle said:
In this thread you've got two people (acoggan and Alex Simmons), who combined probably have more knowledge and experience at interpreting these relationships (ie: resistance vs propulsive variables in cycling) than the entire forum combined, and yet many people still want to argue that they are wrong and you CAN determine power output with sufficient precision to then go and claim rider A produced 10% more power than rider B, or that "X" watts or w/kg is humanly impossible which therefore is "proof" of doping.

It's all b#llsh!t. All you can do is look at large sample sizes and make inferences based on trends in the numbers.

You're building a lot of straw men. First off, it would be pretty simple to determine the power differential expressed as a % among to top 5 guys on Ventoux. I think I'll wait for Ferrari to do it and check his work before I waste my time.

Also, with a few exceptions I really haven't seen anyone claim that XX w/kg is a fine line, or claimed that it's definitive "proof". What I have seen is speculation that Froome's w/kg is equal to that of doped up champions of the past, and this has been confirmed by Hunter Allen who puts Froome's FTP at 6.5 w/kg. To some, that seems highly suspicious for someone with a long history of limited results.
 
131313 said:
Even when w is expressed as w/kg? learn something new every day...
There are a lot of people around here who have a habit of quoting power output expressed in units of watts/kg as if it actually means something, yet they don't even know the bodyweight.


131313 said:
I do agree that the general extrapolations based on TT times is ridiculous though. The way the post was originally worded I thought it was based on the Ventoux climb. About the only comparison you could probably make is compared to Contador. His position is solid, he's obviously able to hold the position as witnessed by his TT pedigree, his equipment is equal or better to Froome's stuff and most importantly he went off around the same time.
The point I was making is that on the climb we need to know w/kg. Are those percent differences posted for Ventoux even expressed as w/kg? If not then they are completely meaningless. If so then we still have the same problem of not knowing exactly the rider's weight, what the wind is doing, the effect of drafting etc etc

You'll note here I'm not defending Froome. I'm not making a call on whether or not he is doping. I'm simply trying to educate anyone who cares, that all these power estimates that have been flying around for the past few days are not the answer to the question of whether Froome is or is not doping.

Fun yes. Ballpark figures yes. Proof of doping.... NO
 
131313 said:
You're building a lot of straw men. First off, it would be pretty simple to determine the power differential expressed as a % among to top 5 guys on Ventoux. I think I'll wait for Ferrari to do it and check his work before I waste my time.
.
So lets say that Froome produced 10% more power (expressed in w/kg) than Contador. So f@#king what? What does that prove? We already know he finished 2min ahead or whatever.
 
Krebs cycle said:
There are a lot of people around here who have a habit of quoting power output expressed in units of watts/kg as if it actually means something, yet they don't even know the bodyweight.

Il vaut mieux lire ça que d'être aveugle :rolleyes:

So, you don't believe that watts/kg has any meaning?

You are hopeless.
 
Krebs cycle said:
You think because a solitary individual is bucking the trend that it has disappeared?

did you forget to read the bit where I said "large sample size"?

Well, if you want to try and assess an individual of course you're only going to use data from that individual relative to whatever your historical trend is.
 
Krebs cycle said:
edit: for the cimbing w/kg you MUST know the exact rider weight, otherwise the error in that alone could be 5-10%.

I'm calling BS on that statement. When calculating Froome's W/kg on Ventoux the difference between Froome weighting 65 and 70 kg is 1.38%.

So since those who have calculated it have used 67kg, they have less than 1% uncertainty in W/kg because of the weight.

Now would you be so kind and explain where you pulled the numbers 5-10% from?
 
Krebs cycle said:
In this thread you've got two people (acoggan and Alex Simmons), who combined probably have more knowledge and experience at interpreting these relationships...


Coggan thinks it is humanly possible to produce 10000 wats for 10 hours straight. I don't think we have to pay much attention to what he says.
 
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Almeisan said:
Coggan thinks it is humanly possible to produce 10000 wats for 10 hours straight. I don't think we have to pay much attention to what he says.

You (deliberately?) misinterpret me: I don't think that producing 10000 W for 10 h straight is absolute proof of doping (and it isn't, as only anti-doping authorities can make that call).
 
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131313 said:
with a few exceptions I really haven't seen anyone claim that XX w/kg is a fine line, or claimed that it's definitive "proof".

Allen Lim, sportscientists.com, Vayer, Lemond...the list is quite long, actually.
 

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