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  1. RChung

    Stages Power Meter 2015

    Most power meter companies are pretty much wedded to a particular hardware approach so once they started down a path the only things they can change might be the price or the firmware. Maybe Stages will improve the door of the battery compartment, or maybe the way they bond to the crank, or...
  2. RChung

    Stages Power Meter 2015

    Hmmm. What updates could there be that would convince you to wait?
  3. RChung

    Cadence, Train to Stregth or Weakness

    IOW, 250 watts using a corncob cassette is faster than 250 watts on a touring cassette.
  4. RChung

    Cadence, Train to Stregth or Weakness

    Hmmm. That was written in 1999? I'm not sure how many many power meter data files the author had examined before writing that but I'm guessing it wasn't a lot.
  5. RChung

    Cadence, Train to Stregth or Weakness

    The x-axis is pedal speed. The y-axis is pedal force. Their product is power, so multiply them. [Edit:] Though if you think about it for a moment, you shouldn't need to. As for your hypothesis about "optimal cadence" and when riders shift gears, that's been examined, too.
  6. RChung

    Cadence, Train to Stregth or Weakness

    Alex said "when riding maximally, as in track standing starts." Here's a plot which shows average pedal force and pedal speed. The yellow dots are track standing starts, the green dots are seated 10x10 sec accelerations. http://www.aboc.com.au/site_images/site-image-repository/fig2se.jpg/image
  7. RChung

    Cadence, Train to Stregth or Weakness

    No. Torque and rotational speed are inversely linear, and power is the product of those two inversely linear things. The product of two things which are inversely linear isn't constant. Lots of people have done this. I encourage you to try it too, so you can see why it doesn't tell you what...
  8. RChung

    What is the conceptual, physiological basis for NP calculation?

    Quote: Originally Posted by bmoberg337 3&4.) You might be familar with the term root mean square (square root of the sum of squares), which is typically used for determining the mean of wave like data. In this case we are raising power values ^4 as described in 2.) so we have to take 4th...
  9. RChung

    Average power math?

    Originally Posted by RapDaddyo I think you're wasting your time, but if you want to take your analysis a bit further, here are some things to do: Break your course down to a set of segments, in which each segment has a relatively constant grade and magnetic heading. I have no idea how...
  10. RChung

    What software for power meter?

    They're not "copied form WKO+." The algorithms pre-dated WKO+.
  11. RChung

    Which Power Meter?

    "Axis cranks" sounds like a WWII pejorative.
  12. RChung

    Garmin Vectors Finally Released

    Yes, we discussed several of these when setting up the protocols for Ray's multi-PM test rides. Of your list the only thing we didn't do was max effort standing starts.
  13. RChung

    Garmin Vectors Finally Released

    If you put two power meters on the same bike, not only are environment conditions (like slope, temperature, wind, total mass) the same but also the rider's choice of standing or sitting, the gears chosen, whether to go easy or to go hard, and to spin fast or push hard. So we can look for the...
  14. RChung

    Garmin Vectors Finally Released

    Ah, so you're familiar with the problem. Excellent. The issues are similar though power meters operate in a far less controlled environment, unit-to-unit variance can be large, and even for a given rider, his or her power production can vary from ride to ride. The statistical problems are really...
  15. RChung

    Garmin Vectors Finally Released

    Are you thinking the bias is constant or maybe linear? Typically, it's not -- or rather, some components of the error are fixed and others aren't. That makes post hoc adjustment difficult, especially since we now have many derived measures that depend on the data stream, not just mean values. A...
  16. RChung

    Garmin Vectors Finally Released

    Well, when power meters are inaccurate they're rarely so reliably inaccurate in a way that's easily correctable like that. When speedometers and odometers are off, they're typically off by a fixed percentage (like, 10%) or else by a fixed percentage plus an offset. Power meters are actually far...
  17. RChung

    Garmin Vectors Finally Released

    Well, not everyone needs to measure their drag, and not all power meters have to satisfy every need for every rider. That said, that paper also includes a protocol for estimating drag without a power meter by doing coast downs. It's more trouble and takes longer but since an inaccurate power...
  18. RChung

    Garmin Vectors Finally Released

    The example is one where the precision was unaffected but the accuracy was, and the consequences. Whether there was operator error involved doesn't affect the consequences of inaccuracy. As for drag testing (I include both aero and rolling resistance) the magnitude of a potential change or...
  19. RChung

    Garmin Vectors Finally Released

    The precision wasn't the same but, as I've said elsewhere, it isn't bad and guiding training is the least demanding use for a power meter. Well, the easiest counter-example is those who don't regularly torque-zero their power meters, or inadvertently zero the torque at the wrong value. In...