Would any of you that got the Power file from Joaquin care to post your assessment of it? Joaquin has yet to forward the data to me so I can't post the graphs for everyone to see. The fact that everyone is so silent, I suppose, means the files support what he said? Probably the reason this thread came to a sudden stop.

And, how does one calculate elevation gain from a power file?

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Frank,
An original Ironman and the Inventor of PowerCranks

"The fact that everyone is so silent, I suppose, means the files support what he said? Probably the reason this thread came to a sudden stop"

Could be. Or maybe people haven't gotten the file? Or maybe the others realize you won't listen to them anyway?

"And, how does one calculate elevation gain from a power file"

An altimeter?

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"Lemond is cycling's version of Rev Jessie Jackson." -johnnyperu 5/18/07
"Just because I suck doesn't mean my bike has to" -rickn 9/2/08

Do Power Tap files have altimeter information?

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Frank,
An original Ironman and the Inventor of PowerCranks

No idea, that's why I was asking.

If someone had a GPS and their power file, they could get the elevation from the GPS. Not sure how to get those two to overlap in one graph though.

That's one of the cool things about the Quark system, it has GPS and altitude. Not that I can afford it...

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"Lemond is cycling's version of Rev Jessie Jackson." -johnnyperu 5/18/07
"Just because I suck doesn't mean my bike has to" -rickn 9/2/08

It was Rcheung who posted if you had the power file one could calculate the altitude data. Love to hear how.

Frank

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Frank,
An original Ironman and the Inventor of PowerCranks

No, your supposition is incorrect--at least, as it applies to me. I've been silent because I haven't yet received the file (and, in general, it's good form not to announce your assessment of a file before you've seen it). However, I seem to recall that Joaquin travels quite a bit so perhaps he's on the road and simply hasn't had the opportunity to send it. I'm sure that once he gets a few minutes he'll send it on.

Ummm...my guess for why it's come to a sudden stop is that no power file has been produced. I sent Joaquin a request both by PM and email and haven't heard a peep. I also know that as of this morning, Mr. Chung hasn't gotten one either. Obviously, the file exists since he posted a plot from downloading it. Now, I understand that Joaquin travels on business at times, so we should probably cut him just a little slack...

As for you second question, that's easy. Mr. Chung figured that out years ago:

http://anonymous.coward.free.fr/...meter/altimeter.html


It's also the basis (i.e. "virtual elevation") for his clever method of field testing CdA:

http://anonymous.coward.free.fr/...cda/indirect-cda.pdf

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http://bikeblather.blogspot.com/

How to turn an expensive power meter into a cheap altimeter.

I agree it is poor form. I suspect your assessment is correct as he is usually pretty good about sending things when he can.

Can you comment on how one calculates altitude from a power file?

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Frank,
An original Ironman and the Inventor of PowerCranks

Interesting. I see you make certain assumptions which might make the absolute number off a bit if the assumptions are wrong but the fact you think you can predict profile by looking at the power is interesting. It would be interesting to see how close you come to the La Mocuera profile from the power file once you get it.

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Frank,
An original Ironman and the Inventor of PowerCranks

Yep...it'll be interesting how close it comes to this:


BTW, using the masses that Joaquin supplied, if his time is taken from the start of the 2nd km, I calculate that he actually was putting out somewhere in the range of 310-320W for the ~7% average grade.

I still would like to know if he's ever tested the static torque values from his PT hub...

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http://bikeblather.blogspot.com/

On a side note, I wish I had something like that to climb around Chicago. I can't fully get a grip on how rough a climb like that might be.

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"Lemond is cycling's version of Rev Jessie Jackson." -johnnyperu 5/18/07
"Just because I suck doesn't mean my bike has to" -rickn 9/2/08

It's just like spending 30 minutes groveling into a stiff headwind :-)

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http://bikeblather.blogspot.com/

I don't understand why he posted the MMPS for the power profile.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Crap, I do that daily on my commute home on the lake. It's not fun.

Either way, anyone received the power file yet? I'm curious on what the smarter-than-I guys have to say about it.

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"Lemond is cycling's version of Rev Jessie Jackson." -johnnyperu 5/18/07
"Just because I suck doesn't mean my bike has to" -rickn 9/2/08

I received a PM from Joaquin this morning stating that he was in Athens on business and would return to Madrid this afternoon. He would send the file when he returned.

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http://bikeblather.blogspot.com/

Me too.

Umm...Robert...I'd wager there ain't too many of them 'round...

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http://bikeblather.blogspot.com/

Just Frank. ;)

Did ya get the file?

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"Lemond is cycling's version of Rev Jessie Jackson." -johnnyperu 5/18/07
"Just because I suck doesn't mean my bike has to" -rickn 9/2/08

Not yet...In the words of Yoda: "You must have patience." :-)

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http://bikeblather.blogspot.com/

Wasn't it, "patience, you must have"?

Regardless, I am sorely lacking.

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"Lemond is cycling's version of Rev Jessie Jackson." -johnnyperu 5/18/07
"Just because I suck doesn't mean my bike has to" -rickn 9/2/08

Just a comment on the power vs speed thing. In my field aero testing I initially was riding on a longer section of road that has some car traffic. I was riding exactly 20mph and was getting variability of about +/-5W or so on a measured ~175W, or close to +/-3% total value. When I switched to a different road with no car traffic that was much more sheltered from the wind, I ended up with variability around +/-1 to 1.5W. Riding out on an open road with cars is going to have a pretty substantial variability to it.

Either way, using time/watts does provide a sanity check, but it isn't accurate enough to judge whether someone's PT is out of calibration. Another SIGNIFICANT assumption is that the power is doled out in a similar manner. Here's a quick experiment you can do with analytic cycling to show why this is important:

10% grade at 350W = 4.4m/s
10% grade at 300W = 3.81m/s
5% grade at 350W = 7.31m/s
5% grade at 300W = 6.5m/s

If you ride 1km at 10% and 1km at 5% grades, choose to ride one at 350W and the other at 300W...you get a combined climb of:
10% at 350W = 227.3s, 5% at 300W = 153.8s, total time 381.1sec, avg power 329.8W
10% at 300W = 262.5s, 5% at 350W = 136.8s, total time 399.3sec, avg power 317.1W
Why is this important you might ask? Because the time/power ratio is different! In the first case it is 1.155s/avgW, in the second case it is 1.26s/avgW. Based on Joaquin's posted pic he has enough variability that it could matter. Not by the 10% in the above simple case, but certainly 30 secs to a minute difference.


On a side note....holy @#%!#$%@#$ hell bikedoc! 460W for 20 minutes! Ouch! That puts my measly 330W to serious shame. I hope you weigh 250lb or I'm going to be really jealous!

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