Power Data Estimates for the climbing stages

[whatsperkilo]

OK maybe I'm not understanding the 'w/kg' thingy, but thanks for shouting Le breton, appreciate that

Using this site, http://2peak.com/tools/map.php, it lets you enter a climb and your weight and your speed etc and then calculates your w/kg.

So it produces the following:
Climb : 2km @ 6% (120m) @ 6mins, bike 7kg.

KG W W/KG VAM
90 385 4.28 1200
80 346 4.33 1200
70 308 4.39 1200
60 268 4.47 1200

As you can see, it gives a different w/kg for each rider of a different weight.
Now what am I missing ? (please be gentle, no shouting )

 

[Ferminal]

Yes that is correct, because the of the body weight/bike weight ratio. Most climbers are going to be 60-70kg so the differences aren't that great. If you don't know weight or are dealing with large quantities of data it's easier just to "normalise" it, so everyone will be assumed to weigh a preferred constant 65-70. So if you're looking at someone who probably weighs less than that their actual W/kg may be a little higher and vice versa. Unless you have a very light climber it's not worth worrying about provided you're just using the numbers as a general indicator.

 

[biopass]

Any data on Horner today?

 

[heart_attack_man]

Courtesy of Alphabet:

Antoine VAYER ‏@festinaboy 54s

Radar Hazallinas : Horner 23mn24s, 7,4 km à 9,49%,18,97 km/h ! 6,34 w/kg. Miraculous ! Like Froome, like Braislford said : "exceptional"

Vayer says 6.34 w/kg.

 

[Tyler'sTwin]

 

[acoggan]

Any data on Horner today?

http://www.srm.de/news/road-cycling/vuelta-a-espana-stage-10/

393 W/65 kg = 6.05 W/kg (at the crank) for 14:52.

 

[21switchbacks]

OK maybe I'm not understanding the 'w/kg' thingy, but thanks for shouting Le breton, appreciate that

Using this site, http://2peak.com/tools/map.php, it lets you enter a climb and your weight and your speed etc and then calculates your w/kg.

So it produces the following:
Climb : 2km @ 6% (120m) @ 6mins, bike 7kg.

KG W W/KG VAM
90 385 4.28 1200
80 346 4.33 1200
70 308 4.39 1200
60 268 4.47 1200

As you can see, it gives a different w/kg for each rider of a different weight.
Now what am I missing ? (please be gentle, no shouting )

What you are missing is that they know neither watts nor kilograms, yet still talk like they do. It is a joke. When you hear "normalized", substitute "made up" or "fudged". It is just some calculation based on time and the particulars of the climb. It is certainly not W/Kg.

 

[Ney the Viking]

What you are missing is that they know neither watts nor kilograms, yet still talk like they do. It is a joke. When you hear "normalized", substitute "made up" or "fudged". It is just some calculation based on time and the particulars of the climb. It is certainly not W/Kg.

Ah yes, some calculations, info about time and elevation certainly says nothing about watt per kg.

It's not like it is possible to calculate the amount of energy required to transport a kg up a mountain and then divide by the amount of time travelled to get a W/kg estimate... It's all witchcraft, nothing to see here move along.

 

[21switchbacks]

Ah yes, some calculations, info about time and elevation certainly says nothing about watt per kg.

It's not like it is possible to calculate the amount of energy required to transport a kg up a mountain and then divide by the amount of time travelled to get a W/kg estimate... It's all witchcraft, nothing to see here move along.

Then label it elevation v time, and not W/Kg (especially, again, when you know neither watts or Kg). If Quintana and Backstedt go up a climb with the same time and some calculation gives them the same W/Kg, then there is nothing to see there. If Backstedt goes up the same climb the next day on the side of the road on a MTB with two flat tires, these calculations will give, again, the same W/Kg. Seriously, they ought to call it something else.

 

[Netserk]

Then label it elevation v time, and not W/Kg (especially, again, when you know neither watts or Kg). If Quintana and Backstedt go up a climb with the same time and some calculation gives them the same W/Kg, then there is nothing to see there. If Backstedt goes up the same climb the next day on the side of the road on a MTB with two flat tires, these calculations will give, again, the same W/Kg. Seriously, they ought to call it something else.

Not with CPL.

 

[Von Mises]

http://www.srm.de/news/road-cycling/vuelta-a-espana-stage-10/

393 W/65 kg = 6.05 W/kg (at the crank) for 14:52.

So, SRM gives 4-5% less power than previous calculations. Why?

 

[acoggan]

Not with CPL.

You mean our model.

 

[acoggan]

So, SRM gives 4-5% less power than previous calculations. Why?

I think the answer you're looking for is "GIGO".

 

[Netserk]

You mean our model.

No I mean Cycling Power Lab.

 

[acoggan]

No I mean Cycling Power Lab.

...which merely implements our model. Ergo, if you wish to be specific about how the calculations are being performed, you should refer to "Martin's model", and/or cite the actual paper, a copy of which can be found here: http://www.academia.edu/239368/Mart...cycling_power._J_Appl_Biomech_1998_14_276-291. To deliberately do otherwise is scientifically unethical.

 

[Gregga]

So, SRM gives 4-5% less power than previous calculations. Why?

Too much weight inaccuracy IMO.
Try "chris horner weight" on google, you'll get from 63 to 66kg on the first two pages of results... 5.95 to 6.25 w/kg...

 

[Race Radio]

Some info from yesterday's stage, and previous stages

Nibali group: 23 min 50 sec
2003 Vinokourov, Mayo: 22 min 39 sec.

Fred measured wind 1m/s in the back till 2-3km to go, then in the face.

2012, Peyresourde E (last 8.71 km, 7.53 %). Janez Brajkovic [60 kg]: 25:01. SRM: 347.0 W

Sources: Grappe, Vayer, Vetoo on twitter

 

[131313]

I think the answer you're looking for is "GIGO".

Yes, the "garbage" being that Horner is 65 kg. The power on his SRM and Vayers caculations are actually dead on when you take into account Horner's actual weight, which is about 62kg or so.

 

[Tyler'sTwin]

@festinaboy "Horner publish 393 watts for 15 ' minutes and says 65 kg =6,05 w/kg. Pinot did 5,9 w/kg on same part and loose 1'. Guess who lies ! and why;"

 

[acoggan]

Yes, the "garbage" being that Horner is 65 kg. The power on his SRM and Vayers caculations are actually dead on when you take into account Horner's actual weight, which is about 62kg or so.

GIGO is GIGO, regardless of where the G arises or goes in.

 

[red_flanders]

GIGO is GIGO, regardless of where the G arises or goes in.

Can you explain what garbage you're talking about in this case then?

 

[131313]

GIGO is GIGO, regardless of where the G arises or goes in.

Nice deflection, but the bottom line is that the calculations are accurate.

 

[Dear Wiggo]

Nice deflection, but the bottom line is that the calculations are accurate.

Glancing at the SRM data::calculated comparisons tweeted on a regular basis, the calculations are within claimed standard power meter accuracy of +/- 1-2% more often than not.

ETA: the irony of certain people quoting GIGO given the trashy study they defended to the death previously. It's painful.

 

[acoggan]

Nice deflection, but the bottom line is that the calculations are accurate.

I'm sorry, I didn't realize you knew Horner's precise mass.

 

[acoggan]

Can you explain what garbage you're talking about in this case then?

Any source of error.