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The Powermeter Thread

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Sep 23, 2010
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elapid said:
Other than doping, power was a big determinant to how Floyd Landis's magic performance on stage 17 of the 2006 TdF played out. His power output was a key factor in determining whether he would survive or not, and whether he would triumph. From this link http://le-grimpeur.net/blog/archives/27:

“A closer look at the data, however, shows that Floyd’s performance that day was well within his physical and mental capacity,” said coach Dr. Allen Lim. “In fact, the most important contributors to Floyd’s comeback was the tactics that developed during the ride – the hesitation by the peloton to chase and Floyd’s intelligent use of water.”

Landis had previously used a power meter in the 2005 Tour and Lim had published all his performance data. Analyzing his stage 17 results in 2006, Lim concluded that “Floyd averaged 281 watts for the entire 5 hour and 23 minute ride”. He went on to add that, “In training before the Tour and even before the Tour of Georgia, Floyd would regularly perform 6-hour rides at 300-310 watt averages.”

Lim also pointed to other figures: “As a point of reference, the overall average for the mountain days in the 2006 Tour de France was 269 watts +/- 16 watts [253-285], while the average in the 2005 Tour de France for the mountains was 274 watts +/- 20 watts [254-294].”

Going into the stage, Lim calculated that if Landis produced 380 watts on the climbs he would stay with the field; anything over and he would put time into them. Producing 370 watts would mean losing time. Using Landis’s stage 17 data, Lim published the following figures for the climbs.

* Col des Saises: 36 min 55 sec at 395 watts (gains time on field)

* Col des Aravis: 16 min 49 sec at 371 watts (loses time on field)

* Col de la Colombiere: 27 min 45 sec at 392 watts (gains time on field)

* Cote de Chatillon: 11 min 7 sec at 374 watts (loses time on field)

* Col de Joux-Plane: 37 min 34 sec at 372 watts (loses time on field)

Comparing the power data above to Landis’s performance in 2005 is illustrative. His best performance was on the mountains stage in the Alps, stage 11 to Briancon where he averaged 285 watts. In two tough consecutive days in the Pyrenees, stages 14 and 15, perhaps more comparable to stage 16 and stage 17 in 2006, for example, Landis averaged only 262 and 249 watts – the second day to Pla d’Adet showing the strain of consecutive stages.

Lim’s data for stage 17 shows several impressive power performances for periods over 30 minutes – 395 watts on the Col des Saises, 392 watts on the Col de la Colombiere, and 372 watts on the Col de Joux Plane. In 2005, on stages 14 and 15, his 30 minute peak power performances were 379 watts and 361 watts. It was these repeated efforts on the stage 17 climbs that were the winning formula.
Do you think Landis could have done that ride without a PM? Me thinks so since 280 watts for nearly 5 hours is pretty much routine for many elite triathletes. The fact that he had a PM making this data known to everyone is not evidence that the PM per se facilitated it. If he had made that move and failed would you blame the PM? Notice, part of what made it look so extraordinary was the "hesitation by the peloton to chase" The only thing, I think, that can be said for certain is we wouldn't know what those numbers were without the power meter. Does anyone know what kind of power LeMond put out when he won the TDF in 1989 over Fignon overcoming a 50 second deficit in 24 km in that time trial? The fact we don't know the wattage doesn't mean it wasn't an extraordinary ride nor that the power wasn't high but it does mean a power meter played essentially no role in it.
 
Apr 21, 2009
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FrankDay said:
Do you think Landis could have done that ride without a PM?
Do you think the PM rode the bike for him Frank?

Me thinks so since 280 watts for nearly 5 hours is pretty much routine for many elite triathletes. The fact that he had a PM making this data known to everyone is not evidence that the PM per se facilitated it.
How would a PM facilitate performance? A PM measures how much power you produce.

Does anyone know what kind of power LeMond put out when he won the TDF in 1989 over Fignon overcoming a 50 second deficit in 24 km in that time trial? The fact we don't know the wattage doesn't mean it wasn't an extraordinary ride nor that the power wasn't high but it does mean a power meter played essentially no role in it.
Had we been able to measure the power prior to that TT you could have told Fignon that he should have experimented with aero bars and at least worn an aero helmet seeing he lost the Tour be 8 seconds.
 
Sep 23, 2010
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CoachFergie said:
Cool "However, Blanco's decision to use Pioneer's Android-powered SGX-CA900 display earns its riders another benefit: a visual display of what direction they're applying that power, which can help users analyze and improve their pedaling stroke." So, something a little more than a simple power meter. (not that anyone cares LOL)

Times they are a changing.

Edit: pretty soon we will have to merge the power meter and the pedaling technique thread.
 
Sep 23, 2010
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CoachFergie said:
Had we been able to measure the power prior to that TT you could have told Fignon that he should have experimented with aero bars and at least worn an aero helmet seeing he lost the Tour be 8 seconds.
No you wouldn't have (or if you did he wouldn't have believed you). Fignon's power (if he had measured it and compared it to LeMond) would have never predicted LeMond would win because they would have been pretty close. Fignon would have never listened to anyone about the aerodynamics because aerodynamics simply weren't seen as that important back then. Much like we see now when people argue that power determines performance. Many lose the big picture when they focus on power.
 
Apr 21, 2009
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FrankDay said:
Cool "However, Blanco's decision to use Pioneer's Android-powered SGX-CA900 display earns its riders another benefit: a visual display of what direction they're applying that power, which can help users analyze and improve their pedaling stroke." So, something a little more than a simple power meter. (not that anyone cares LOL)

Times they are a changing.

Edit: pretty soon we will have to merge the power meter and the pedaling technique thread.
As we will for the iCrank we await the validation of both the power meter and pedalling analysis measurement for the Pioneer power meter.
 
Apr 21, 2009
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FrankDay said:
No you wouldn't have (or if you did he wouldn't have believed you). Fignon's power (if he had measured it and compared it to LeMond) would have never predicted LeMond would win because they would have been pretty close. Fignon would have never listened to anyone about the aerodynamics because aerodynamics simply weren't seen as that important back then. Much like we see now when people argue that power determines performance. Many lose the big picture when they focus on power.
Yes, because they never used aero helmets, disc wheels, aerodynamic bicycles or skinuits back in the 80s. Fignon ignored the available data at the time and it cost him the Tour. That is the Big Picture.

 
Sep 23, 2010
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CoachFergie said:
Yes, because they never used aero helmets, disc wheels, aerodynamic bicycles or skinuits back in the 80s. Fignon ignored the available data at the time and it cost him the Tour. That is the Big Picture.

Fignon had two disk wheels and a pretty good position. Since we don't have the power data we don't know if Lemond won or Fignon lost based upon aerodynamics or power (or some combination). LeMond did ride all out. Everyone assumes it was aerodynamics but nobody really knows. Either way, I suspect his power was pretty high despite not having a PM.
 
Apr 21, 2009
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FrankDay said:
Fignon had two disk wheels and a pretty good position. Since we don't have the power data we don't know if Lemond won or Fignon lost based upon aerodynamics or power (or some combination). LeMond did ride all out. Everyone assumes it was aerodynamics but nobody really knows. Either way, I suspect his power was pretty high despite not having a PM.
Drag data or power data. Either way he lost the Tour because he ignored the available data.
 
Sep 23, 2010
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CoachFergie said:
Drag data or power data. Either way he lost the Tour because he ignored the available data.
What data did he have and then ignore that caused him to lose? It is a simple matter that LeMond beat him that day. It is the case with most races.
 
Apr 21, 2009
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FrankDay said:
What data did he have and then ignore that caused him to lose? It is a simple matter that LeMond beat him that day. It is the case with most races.
Just a bad day? These days we can measure it so don't have to guess.
 
Sep 23, 2010
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RChung said:
The signal-to-noise ratio in this thread makes it not worth following.
Perhaps that is because you choose to submit only a little of your own signal. Or, would more participation on your part make the noise worse?
 
Apr 21, 2009
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Checked the calibration of my Powertap and SRM today. Used a known weight of 20.22kg.



SRM slope was out by 0.10%. Powertap out by 2.5%. There is the catch with the cheaper PM, can't change the calibration of a Powertap.

Questions!

How known should the weight be? Local post office measured to 2 decimals. Does it need to be three.

To hang the weight I took the front wheel out and put forks on a ledge. Made sure the crank arm was horizontal. Is this acceptable?

Should I bother changing the slope on my SRM from 34.1 to 34.13?
 
Right, let's draw the line...

This thread is for discussions about power meters, those things which measure Watts.

Watts may not be interesting to everyone but the reality is many people at all levels (for whatever reason) look at that information.

If you are not interested in Watts I think there has been ample opportunity to make that point in this thread. Can we please now move on and return to the initial aim of the thread - to provide guidance in regards to these tools which measure Watts. Any posts we deem contrary to this will be deleted.
 
Apr 21, 2009
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Thank you!

Nice video on how to calibrate a Quarq power meter...

http://www.youtube.com/watch?v=4IZL3QXtYv0

Which gives you some handy tips for doing the test on other models.

http://www.cyclingpowerlab.com/PowerMeterCalibration.aspx

Tells you how to calibrate Powertap, SRM and Quarq although to change the slope in the Quarq you need a iPhone (or Touch or Pad) and a Wahoo dongle and download the free Qualvin software. There is Qualvin for Android now although my phone isn't ANT+ compatible and haven't seen a dongle available yet.

http://www.wickedrides.com.au/blog/?q=node/190

This blog had a really good excel spreadsheet which I used to double check the numbers from the cyclingpowerlab page.
 
Mar 18, 2009
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Ferminal said:
Right, let's draw the line...

This thread is for discussions about power meters, those things which measure Watts.

Watts may not be interesting to everyone but the reality is many people at all levels (for whatever reason) look at that information.

If you are not interested in Watts I think there has been ample opportunity to make that point in this thread. Can we please now move on and return to the initial aim of the thread - to provide guidance in regards to these tools which measure Watts. Any posts we deem contrary to this will be deleted.
+1. Thank you very much!
 
Apr 21, 2009
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An odd comment to make when he won.

I discourage my riders from looking at theirs in races for safety reasons.
 

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