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Vuelta discussion
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| Stairs |
Posted on 13-09-2008 18:54
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They'll be showing the stage again on Danish TV later tonight and I'll have my watch at my side 
My personal guess would be 41 minutes which would give all the numbers a little more sense.
Sastre is definitely way below his Tour-level - you don't have to look at numbers to figure that out. Astana is benefitting from their no-starter in the Tour - and I'm really looking forward to Damsgaard publishing Astana's test results.
Never.
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| drugsdontwork |
Posted on 13-09-2008 18:55
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I need to get this straight in my head.
As I understand it, people are working out the power output of a cyclist using the following formula:-
Power Output = (Force x Distance)/Time
Where:
Force = Weight of rider (in Newtons)
Distance = Height climbed (in meters)
Time = Time taken for climb (in seconds)
Is this right?
Nobody is normal
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| brun sweater |
Posted on 13-09-2008 18:58
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I just use this site 
https://www.kreuzotter.de/english/espe...espeed.htm |
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| Aquarius |
Posted on 13-09-2008 19:00
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It's more complicated than that actually. There are other factors to consider, such as wind resistance, mechanical resistance.
And of course there are constants and various coefficients to apply to get Watts out of what you've written there.
But the basic idea is indeed what you wrote. |
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| drugsdontwork |
Posted on 13-09-2008 19:10
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Thanks for the prompt explination.
I'll declare my hand now so no one thinks I'm hiding anything, I've done a degree in mechanical engineering, so I do know a bit about physics etc. However, the reason I'm asking these questions is just to get a better understanding.
The next question I've got to ask is how does the relative wattage calculation work? As I see it, the weight of a rider has a direct influence on the speed(and subsequent power generated) at which they climb?
Thanks for the patience.
Nobody is normal
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| brun sweater |
Posted on 13-09-2008 19:20
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relative is just with a total weight of 78 kg |
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| issoisso |
Posted on 13-09-2008 19:23
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no, relative is
if guy who weighs (for instance 67 including bike) did (for instance 270 watts) then how many watts does that performance equate to for a 78kg (including bike) guy?
67 is to 78 as 270 is to X
X is your relative power so that different riders can be compared.
The preceding post is ISSO 9001 certified
"I love him, I think he's great. He's transformed the sport in so many ways. Every person in cycling has benefitted from Lance Armstrong, perhaps not financially but in some sense" - Bradley Wiggins on Lance Armstrong
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| Aquarius |
Posted on 13-09-2008 19:40
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drugsdontwork wrote:
Thanks for the prompt explination.
I'll declare my hand now so no one thinks I'm hiding anything, I've done a degree in mechanical engineering, so I do know a bit about physics etc. However, the reason I'm asking these questions is just to get a better understanding.
The next question I've got to ask is how does the relative wattage calculation work? As I see it, the weight of a rider has a direct influence on the speed(and subsequent power generated) at which they climb?
Thanks for the patience. If you did a mechanical engineering degree in physics then you're worth some technical explanations.
I must have written this half a dozen of times at least, but nevermind.
There are basically three strengths that apply to a solid body moving onto a solid plan : gravity, fluid resistance (air most of times), and mechanical resistance.
Gravity is directly affected by weight : an object located at some height has more energy than another object of the same weight located under : E = m.g.h (m for mass, g is the gravity constant, h is the height). That's why, for comparison purposes, we consider that all riders weigh the same (70 kg, plus 8 kg of bike, water and equipment).
Air resistance is quite futile at the speeds cyclists climb mountains (under 23 km/h you can afford to not count it), although it's included in the real formula. When it's windy you also have to consider it though.
Then mechanical resistance consists of both the road resistance (variable according to the road quality) and of the bike output (the better the bike, the better its output).
The real formula also considers hygrometry and temperature, as they affect air resistance and road output.
I think there are other factors too, not sure though. |
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| drugsdontwork |
Posted on 13-09-2008 19:45
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I can see what people are trying to get at. It's the same thing as giving each rider a value in watts generated per kg and then comparing them.
It's an interesting concept, but it makes some large assumptions about power generation in a cyclist being linear to weight.
Thanks for the info.
Nobody is normal
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| issoisso |
Posted on 13-09-2008 19:50
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drugsdontwork wrote:
I can see what people are trying to get at. It's the same thing as giving each rider a value in watts generated per kg and then comparing them.
It's an interesting concept, but it makes some large assumptions about power generation in a cyclist being linear to weight.
Thanks for the info.
Nope, It makes an assumption that the distance traveled will be impacted by weight, and it is, since you're going uphill
The preceding post is ISSO 9001 certified
"I love him, I think he's great. He's transformed the sport in so many ways. Every person in cycling has benefitted from Lance Armstrong, perhaps not financially but in some sense" - Bradley Wiggins on Lance Armstrong
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| rovven7 |
Posted on 13-09-2008 19:55
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Cunego started the Angliru 1 minute after the favourites, because of a puncture on the previous descent. Having chased the peloton alone on the easy gradients on the beginning, without anybody in front of him, i think he did a fantastic job in getting to the finish after 2 minutes and 43 seconds. Without that bad luck, he would've been as good as Leipheimer and Sastre, without being in top shape, yet. Yeah, i know, i'm a fan, but for me this is proof enough that he IS a climber. |
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| Stairs |
Posted on 13-09-2008 19:56
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Or maybe he's suddenly become tattoo-less!
Never.
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| doddy13 |
Posted on 13-09-2008 19:58
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Stairs wrote:
Or maybe he's suddenly become tattoo-less!
ahahahahahaha
best thing i've heard all day
There's no point slapping a schleck - Sean Kelly on "Who needs a slap"
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| rovven7 |
Posted on 13-09-2008 20:00
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He's still Doping free. And yeah, i know, it's easy to stand on a chair and question somebody's performance. |
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| Aquarius |
Posted on 13-09-2008 20:00
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drugsdontwork wrote:
I can see what people are trying to get at. It's the same thing as giving each rider a value in watts generated per kg and then comparing them.
It's an interesting concept, but it makes some large assumptions about power generation in a cyclist being linear to weight.
Thanks for the info. True, but keep in mind that it's relative powers, not real ones. We'd need to know much more about a lot of weight related parameters to get more accurate numbers.
Only muscles produce power, the rest of the body is either a way to transmit that power, either useless. We can't really measure the muscular mass of riders to make calculations. Then there's sweating, the more you sweat, if you don't drink, the more your output decreases, but the lighter you get.
Then again, the extra 8 kg are also disputable, since the amount of water and food carried varies all the way up the climb.
Assumptions are necessary for purposes like ours. |
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| Stairs |
Posted on 13-09-2008 20:05
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rovven7 wrote:
He's still Doping free. And yeah, i know, it's easy to stand on a chair and question somebody's performance.
Nah, it was just an obvious - and bad - joke. I was glad to see Cunego up there, no matter what conclusions you make of it :-P
Never.
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| drugsdontwork |
Posted on 13-09-2008 20:08
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I agree Aquarius.
The only problem I have is that it's just a little dangerous to quote relative wattages as gospel when there are may assumptions in them.
However I accept that, making an assumption that all the riders we are comparing (i.e. climbers) have a similar body makeup, it gives a general indication of rider "ability".
Nobody is normal
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| Aquarius |
Posted on 13-09-2008 20:25
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Yeah, well, more than long and complicated formulas, it should be taken as a conversion of the times it took the riders to climb one mountain into a figure, and a way to compare their performances from one mountain to another, and their evolution through their careers.
The real value, their real wattage doesn't matter that much in the end. |
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| drugsdontwork |
Posted on 13-09-2008 20:35
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That raises an interesting point.
Has anyone looked at the variation in power generation of single riders over their entire career.
It would be interesting to see how known dopers and "clean" riders' outputs varied ovet the years. You could tie this in to when certain drugs came on the market and when reliable tests for those drugs were developed. You cou also look at the performance of riders before and after doping bans. It might give a good indication of how reliable power calculations are.
Sounds like a PhD for someone.
Anyway I think I'm getting a little "off-topic".
Nobody is normal
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| issoisso |
Posted on 13-09-2008 21:05
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drugsdontwork wrote:
That raises an interesting point.
Has anyone looked at the variation in power generation of single riders over their entire career.
It would be interesting to see how known dopers and "clean" riders' outputs varied ovet the years. You could tie this in to when certain drugs came on the market and when reliable tests for those drugs were developed. You cou also look at the performance of riders before and after doping bans. It might give a good indication of how reliable power calculations are.
Indeed we do most of that on this forum
Mostly note how in years when a test for a new drug comes into view, some top rider's career invariably goes in the gutter (Garzelli, Mayo, etc.) since different people respond differently to different drugs. A drug that has little effect in most people will have a huge effect on a select few. That's the main reason doping is unfair: it's not so much a question of how good you are, it's a lot to do with how much of an effect drugs have on you.
But I digress. About your before-and-after-doping-bans, it's simple: wattages show everyone comes back to the exact same performances as before, which trumps the "they've learned their lesson" argument because they haven't. They come back to dope again.
The preceding post is ISSO 9001 certified
"I love him, I think he's great. He's transformed the sport in so many ways. Every person in cycling has benefitted from Lance Armstrong, perhaps not financially but in some sense" - Bradley Wiggins on Lance Armstrong
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