Power Data Estimates for the climbing stages

[Merckx index]

Alberto Contador

Giro d'Italia 2011, Stage 9, Final climb Monte Etna, from 8 Km remaining to 1 Km remaining = 7 Km

Elevation / Höhenmeter [m] : 466 m
Distance / Streckenlänge [Km] : 7.0 Km
Time in seconds / Fahrzeit in Sekunden [sec] : 1020 = 17 min 10 sec = 17:10
Weight rider / Gewicht Fahrer [kg] : 62 kg
Weight bicycle, clothes etc. / Gewicht Fahrrad [kg] : 8 kg

Grade / mittlere Seigung : 6.6 %
Average speed / mittlere Geschwindigkeit : 24.4 Km/h
Total weight / Gesamtgewicht : 70.0 kg

Power : 411.0 Watt
Power / kg : 6.6 Watt / kg

I’m not sure how you got 6.6 watts/kg. Based on the above data, Bert’s VAM was 1628, which for a 6.6% grade corresponds to 6.17 watts/kg.

From the way you present the data, you seem to be calculating watts first, then dividing that by Contador’s weight (not the total weight of rider plus bikce). But you can’t determine watts directly from climbing data, you can only calculate watts/kg. If two riders of different weight have identical times on a climb, their watts/kg values will be identical, though their watts will be different.

 

[Le breton]

I’m not sure how you got 6.6 watts/kg. Based on the above data, Bert’s VAM was 1628, which for a 6.6% grade corresponds to 6.17 watts/kg.

From the way you present the data, you seem to be calculating watts first, then dividing that by Contador’s weight (not the total weight of rider plus bikce). But you can’t determine watts directly from climbing data, you can only calculate watts/kg. If two riders of different weight have identical times on a climb, their watts/kg values will be identical, though their watts will be different.

If two riders of different weight have identical times on a climb, their watts/kg values will be identical
Not exactly as air resistance plays a part and the bicycles represent a higher fraction of the total weight for the lighter rider. Generally speaking a lighter rider will need a bit more watts/kg, but I am splitting hair.

But you can’t determine watts directly from climbing data, you can only calculate watts/kg.

I don't understand what you mean. Of course you can calculate watts from climbing data, you just need to have all the relevant data.

However, if the wind was as strong as suggested it is a bit risky to draw conclusions from that climb in terms of watts/kg, only lower limits if the wind was always against the rider.

 

[Le breton]

Alberto Contador

Giro d'Italia 2011, Stage 9, Final climb Monte Etna, from 8 Km remaining to 1 Km remaining = 7 Km

Elevation / Höhenmeter [m] : 466 m
Distance / Streckenlänge [Km] : 7.0 Km
Time in seconds / Fahrzeit in Sekunden [sec] : 1020 = 17 min 10 sec = 17:10
Weight rider / Gewicht Fahrer [kg] : 62 kg
Weight bicycle, clothes etc. / Gewicht Fahrrad [kg] : 8 kg

Grade / mittlere Seigung : 6.6 %
Average speed / mittlere Geschwindigkeit : 24.4 Km/h
Total weight / Gesamtgewicht : 70.0 kg

Power : 411.0 Watt
Power / kg : 6.6 Watt / kg

Source: [ http://www.rst.mp-all.de/bergauf.htm ]

Note: Strong head wind and cross wind. Power value is likely higher.

Many thanks.

I plugged in your numbers in analytiiccycling .com, with
CdA = 0.375 m^2
air density = 1.05 ( I didn't make a search for the exact average altitude or temperature)
and used your other data, correcting one obvious mistake 17 :10 = 1030 s, not 1020s.

Result = 391 watts

add 2.5 % for transmission loss = 401 watts

401/62 = 6.47 watts/kg

which is not that far from your value.

Next question is how good are the input data and first of all the one that matter most : altitude difference of 466m and time (1030 s.)?

 

[FoxxyBrown1111]

W/o being an detailed expert in Watt/kg, i can still read. What i see here is a dramatic drop of power compared to the Armstrong years. We are clearly in a better shape now ("doping-wise"). And remember, Contadors results from today came from a shorter and flatter (is that word existing? ) mountain than those from the super performance years.

 

[Lanark]

W/o being an detailed expert in Watt/kg, i can still read. What i see here is a dramatic drop of power compared to the Armstrong years. We are clearly in a better shape now ("doping-wise"). And remember, Contadors results from today came from a shorter and flatter (is that word existing? ) mountain than those from the super performance years.

I don't, outside of the Alp D'Huez time trial, I doubt Armstrong topped 6.6w/kg more than a couple of times, if at all. This all depends on how reliable those data from above are obviously.

 

[FoxxyBrown1111]

http://www.rst.mp-all.de/bergauf.htm

(Armstrong 470 Watt on 14.5 km up to Alpe)

http://www.sportmedinfo.de/radsport.htm

(Armstrong 488 Watt on Sestriere; 6.8 Watt/kg w/o bike)

http://www.netzathleten.de/Nachrich...rgieverbrauch/Radsport/-8659720177160281088/a

(Armstrong 482 Watt; 6.7 Watt/kg)

etc. etc.

All wayyy above Contaros performance today on longer Climbs

P.S.: Of course many asumptions are made on that Watt measurments, but the trend is clear: ArmstrongPantani/Indurain/Ullrich were all way above todays performances...

 

[Bumeington]

This data looks reasonable for the best climber in the world for a 17 minute effort. No point comparing to 40 min climbs like alpe d'huez. An interesting comparison would be today to Verbier 2009 as that was around a 20 minute effort, my bet is the W/kg are lower in 2011 compared to 2009

 

[roundabout]

This data looks reasonable for the best climber in the world for a 17 minute effort. No point comparing to 40 min climbs like alpe d'huez. An interesting comparison would be today to Verbier 2009 as that was around a 20 minute effort, my bet is the W/kg are lower in 2011 compared to 2009

6.73 w/kg for Verbier according to Ferrari.

 

[FoxxyBrown1111]

Bomeington

I would agree with that. I think too much panic is going around in the forum. May the passport not be perfect, it´s an improvement, coz the riders are feared, thus forced to max "micro dope". Those who still couldn´t believe in the (some) change got busted big time (DiLuca, Mosquera, Pellizotti to name a few big names). The true talent of DiLuca was seen today. A clean 25 mins down performance.

 

[Merckx index]

I don't understand what you mean. Of course you can calculate watts from climbing data, you just need to have all the relevant data.

What I mean is that VAM is directly proportional to watts/kg (neglecting wind resistance which is very trivial on steep slopes, and correcting for the fact that maximum output occurs on some gradient). You can only calculate total watts from VAM values by first determining watt/kg, then multiplying by the rider’s weight. This is why when you see discussions of climbing power, the data are commonly normalized to 70 kg. Because the raw data only give you watts/kg.

I plugged in your numbers in analytiiccycling .com, with
CdA = 0.375 m^2
air density = 1.05 ( I didn't make a search for the exact average altitude or temperature)
and used your other data, correcting one obvious mistake 17 :10 = 1030 s, not 1020s.

Result = 391 watts

add 2.5 % for transmission loss = 401 watts

401/62 = 6.47 watts/kg

which is not that far from your value.

I plugged in the values and got 361-388 watts, depending on certain assumptions. But the upper limit is obtained by using a high value for frontal area, which certainly would not be the case for Bert or any other climber, and which in any case is reduced in its effect at high altitudes.

Power is defined as raising a certain weight a certain distance in a certain time. This was the original definition of horsepower. VAM is defined as raising an undefined weight a certain distance in a certain time. So if you multiply VAM by weight, you get power; or power equals VAM divided by weight. It is not watts, because the units are different, but it is directly proportional to watts, and so can be easily transformed.

All those correction factors like frontal area, rolling resistance, gradient, etc., are basically ways of converting the actual power values to the output a rider has to have to manifest that power. Imagine a weight lifter who lifts a certain weight a certain distance in a certain time. This is the actual power manifested. But in the process of lifting that weight, the lifter may have to overcome air resistance, friction, and so forth, so the actual power that his body puts out is slightly higher. However, the outcome of a weight lifting contest does not take this into account, it’s determined by the manifested power.

In the same way, VAM is the manifested power, divided by the rider’s body weight.

 

[hfer07]

now that Contador values are sorted out- I'm asking.........

What about Rujano's data?

 

[Mrs John Murphy]

How does this compare to his figures for 2007 ie peyresourde, Aubisque? or figures for the 2008 Giro when he was beating super-charged Ricco and DDL.

That was a super-charged tour and it might shed some light on if we are back to pre-bio-passport performances.

 

[Le breton]

I’m not sure how you got 6.6 watts/kg. Based on the above data, Bert’s VAM was 1628, which for a 6.6% grade corresponds to 6.17 watts/kg.

From the way you present the data, you seem to be calculating watts first, then dividing that by Contador’s weight (not the total weight of rider plus bike). But you can’t determine watts directly from climbing data, you can only calculate watts/kg. If two riders of different weight have identical times on a climb, their watts/kg values will be identical, though their watts will be different.

Using the data from Halamala and taking a rolling resistance(r.r.) of 0.004
AC must has produced
5.02 watts/kg against gravity
0.29 watts/kg against r.r.
total so far 5.31 watts/kg

basically you are saying that at a velocity of 24.5 km/h AC, not drafting, only needs 6.17 -5.31 = 0.86 watts/kg to fight air resistance.
0.86 times 62 = 53 watts
if the air density was around 1.0 kg/m^3 (20°C at 1600m altitude)
his CdA must have been 0.335 m^2

And the air must have been still.

What these numbers show is that at 24.5 km/h the air resistance is far from negligible even on a 6.6% slope, being 14% of the total in your estimate (more on this below).

( From personal experience I preferred to take 0.375m^2, but can't prove that 0.335 m^2 is closer to the truth for AC on Etna.)
If you take 0.375 instead of 0.335, 6.17 watts/kg becomes 6.27 watts/kg.

We don't know if the transmission losses of about 2.5%, ie about 0.15 watts/kg are included in those 6.17. If they are the CdA was only 0.28 m^2, which seems hard to believe.So, as you can see, it's not that simple to interpret VAM as I explained to Ferrari on cyclingnews a number of years back. At the time he seemed to take notice.

Same can be said about going from VAM to watts/kg, except on real steep mountains as the speed drops.

I let the question of the wind out so as not to bring in even more hypothetical numbers

 

[marcozero]

Air resistance while climbing

Numbers on Drafting
By: Michele Ferrari
http://www.53x12.com/do/show?page=article&id=89

"It is interesting to note that at 22-24 km/h the saving is about 40w: a quite considerable advantage also for speeds that are typical of climbing, corresponding to about 10% in power for a cyclist that pushes 400w. "

And with head wind of 10 or 20 km/h the advantage of drafting would reach 60 to 120w... Not exactly negligible.

In the same article theres's an interesting note about the effect of motorcycles... measured in blood units!

 

[Merckx index]

So, as you can see, it's not that simple to interpret VAM as I explained to Ferrari on cyclingnews a number of years back. At the time he seemed to take notice.

Same can be said about going from VAM to watts/kg, except on real steep mountains as the speed drops.

Yes and no. Again, as I said before, all those little factors like rolling resistance, wind resistance, transmission loss, etc., do factor in to calculations if you want to determine the watts the rider is putting out. But VAM is all that is necessary if you want to determine the actual watts manifested, the useful watts, the watts that are not burned up fighting various forms of resistance other than gravity.

What this means is that if you want to compare a rider's current performance with a past performance, by that rider or any other rider, which was the point of this thread, VAM is really all you need. It's perfectly legitimate to compare VAM values of different riders or the same rider at different times, because most of those other factors will be similar. For example, assuming there is little or no wind (if there is a strong head wind, all bets are off), wind resistance will be similar, because speed will be similar, because the gradient on which the climb occurs will not be all that different. Generally speaking, average gradient of major climbs that decide GTs is in the 6-9% range, so the speeds of these climbs are not all that different. Rolling resistance will be similar. For a particular rider, cross sectional area will be similar, and given that contenders are all very good climbers with generally similar body types, cross-sectional area will not be that different, either.

For example, let's suppose 20% of the watts put out actually go to factors other than overcoming gravity. My contention is that this 20% will not vary that much from rider to rider and climb to clim, maybe 10-20%, so the actual error in using VAM to compare different riders/climbs will be 5% or less.

 

[Escarabajo]

Yes and no. Again, as I said before, all those little factors like rolling resistance, wind resistance, transmission loss, etc., do factor in to calculations if you want to determine the watts the rider is putting out. But VAM is all that is necessary if you want to determine the actual watts manifested, the useful watts, the watts that are not burned up fighting various forms of resistance other than gravity.

What this means is that if you want to compare a rider's current performance with a past performance, by that rider or any other rider, which was the point of this thread, VAM is really all you need. It's perfectly legitimate to compare VAM values of different riders or the same rider at different times, because most of those other factors will be similar. For example, assuming there is little or no wind (if there is a strong head wind, all bets are off), wind resistance will be similar, because speed will be similar, because the gradient on which the climb occurs will not be all that different. Generally speaking, average gradient of major climbs that decide GTs is in the 6-9% range, so the speeds of these climbs are not all that different. Rolling resistance will be similar. For a particular rider, cross sectional area will be similar, and given that contenders are all very good climbers with generally similar body types, cross-sectional area will not be that different, either.

No.

You have to take into account the wear and tear of the wind. It will affect your performance completely. I am not sure why you are saying this. VAM numbers are close enough with no wind conditions only. Sorry but it is misleading when a strong head wind hits the rider.

 

[Merckx index]

No.

You have to take into account the wear and tear of the wind. It will affect your performance completely. I am not sure why you are saying this. VAM numbers are close enough with no wind conditions only. Sorry but it is misleading when a strong head wind hits the rider.

Apparently you didn't read my post carefully. Yes, if there is a strong head wind, there are problems. But if there is a strong head wind, the detailed calculation is also problematic, because the strength of the wind will vary at different portions of the climb, maybe at different times, etc. So it becomes very difficult to calculate watts even trying to take into account wind.

Other than that, the biggest problem with using VAM is that the gradient ideally should be fairly consistent. If there are false flats, that will throw off the calculations to the point where they may be useless. A rider will go up a steady 7% gradient faster than a gradient that averages 7%, but has false flats mixed in with much steeper portions. Also, every rider has an optimal gradient where he puts out maximal power. This varies from rider to rider, but that variation is not taken into account in the power calculations. It's assumed that the optimum is the same for everyone.

 

[Escarabajo]

Apparently you didn't read my post carefully. Yes, if there is a strong head wind, there are problems. But if there is a strong head wind, the detailed calculation is also problematic, because the strength of the wind will vary at different portions of the climb, maybe at different times, etc. So it becomes very difficult to calculate watts even trying to take into account wind.

Other than that, the biggest problem with using VAM is that the gradient ideally should be fairly consistent. If there are false flats, that will throw off the calculations to the point where they may be useless. A rider will go up a steady 7% gradient faster than a gradient that averages 7%, but has false flats mixed in with much steeper portions. Also, every rider has an optimal gradient where he puts out maximal power. This varies from rider to rider, but that variation is not taken into account in the power calculations. It's assumed that the optimum is the same for everyone.

Fair enough.

That's why in the past I have used range of values for each input variable that matters in order to find out the final power range. What you are saying is true, you would need to do a calculation by small length sections knowing the angle in which the wind is hitting the rider. That is rather complicated, so that's why we use averages, which is the best we can do.

 

[Escarabajo]

Bomeington

I would agree with that. I think too much panic is going around in the forum. May the passport not be perfect, it´s an improvement, coz the riders are feared, thus forced to max "micro dope". Those who still couldn´t believe in the (some) change got busted big time (DiLuca, Mosquera, Pellizotti to name a few big names). The true talent of DiLuca was seen today. A clean 25 mins down performance.

I am beginning to think that he is riding clean.

 

[Bala Verde]

Numbers on Drafting
By: Michele Ferrari
http://www.53x12.com/do/show?page=article&id=89

"It is interesting to note that at 22-24 km/h the saving is about 40w: a quite considerable advantage also for speeds that are typical of climbing, corresponding to about 10% in power for a cyclist that pushes 400w. "

And with head wind of 10 or 20 km/h the advantage of drafting would reach 60 to 120w... Not exactly negligible.

In the same article theres's an interesting note about the effect of motorcycles... measured in blood units!

Interesting quote:

Another cyclist covered alone the same 1 km stretch of flat road at 48 km/h, expressing an average power of 410w.
He repeated the performance with a motorcycle 15m ahead of him: the average was 385w, a saving of 6%.
Whenever we see the multitude of photographers motorbikes repeatedly hovering around the leading rider in a race, such considerable advantage is automatically given to him: it is as if they temporarily subjected him to an instantaneous transfusion of 1-2 units of blood...

Does anyone know if there has been increase in the number of motorcycles during major races, to cover the race. Obviously the ones in the lead, and especially the main contenders, get all the attention. In effect, protagonists could thus have drafting advantages on major climbs. When a small group of favorites explodes, the stragglers are not always covered, but do they have motos around all the time, or do they 'share' a moto?

 

[iZnoGouD]

i'am curious to see the numbres from this next 3 stages

 

[halamala]

Monte Zoncolan: Anton climbed 5.9 W/kg, Contador 5.8 W/kg

Giro d'Italia 2011, Stage 14, Final climb Monte Zoncolan, from 10 Km banner to finish line = last 10.0 Km

Igor Anton

Elevation / Höhenmeter [m] : 1194 m
Distance / Streckenlänge [Km] : 10.0 Km
Time in seconds / Fahrzeit in Sekunden [sec] : 2439 = 40 min 39 sec = 40:39
Weight rider / Gewicht Fahrer [kg] : 60 kg
Weight bicycle, clothes etc. / Gewicht Fahrrad [kg] : 8 kg

Grade / mittlere Seigung : 11.9 %
Average speed / mittlere Geschwindigkeit : 14.7 Km/h
Total weight / Gesamtgewicht : 68.0 kg

Power : 357.3 Watt
Power / kg : 5.9 Watt / kg

Alberto Contador

Elevation / Höhenmeter [m] : 1194 m
Distance / Streckenlänge [Km] : 10.0 Km
Time in seconds / Fahrzeit in Sekunden [sec] : 2472 = 41 min 12 sec = 41:12
Weight rider / Gewicht Fahrer [kg] : 62 kg
Weight bicycle, clothes etc. / Gewicht Fahrrad [kg] : 8 kg

Grade / mittlere Seigung : 11.9 %
Average speed / mittlere Geschwindigkeit : 14.5 Km/h
Total weight / Gesamtgewicht : 70.0 kg

Power : 362.0 Watt
Power / kg : 5.8 Watt / kg

Source: [ http://www.rst.mp-all.de/bergauf.htm ]

*

Simoni is a record holder: 38:59, Giro 2007 (last 10 Km). Basso's time was 40:17 in 2010 (last 10 Km).

 

[18-Valve. (pithy)]

Giro d'Italia 2007, stage 17, Monte Zoncolan, power data estimates

http://letour.over-blog.com/article-10643112.html

 

[Sophistic]

i would say its a healthy sign how "slow" Anton & Co were yesterday

 

[Frosty]

You'd hope so. Then again today's stage is tough so i doubt they were going 100% - last year had a rest day the next day but was probably a harder stage before the Zoncolan.