Bike computer readouts.

Gravity Aided

Legendary Member
Location
Land of Lincoln
On the original video on YouTube, he mentions "- The power readings are accurate (calibrated/zeroed unit)." I figure that is the top readout, as the bottom is cadence and the middle is kph and heartrate is over on the right. But that's only a guess at this point. Not knowing much more about cardiology, either, I would have to say that the heart rate seems high, but who knows what mine would look like on a KOM descent in the Victorian Alps.
 

Rob3rt

Man or Moose!
Location
Manchester
Power is the product of cadence and torque. So other than knowing that for a cadence of zero, power is zero, you can not expect to know power for any other cadence value since you have no clue as to the torque being applied, this is what the power meter is measuring.
 
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Rob3rt

Man or Moose!
Location
Manchester
As for heart rate, no wonder it is high if 500+ W are frequently being dispensed. Given HR reacts slowly to effort (making it useless for gauging effort in short interval training sessions) it will not increase or decrease instantly when the power rises or drops, there is a delay, therefore with frequent efforts, an effort begins and ends, the body reacts and raises heart rate, this is somewhat delayed so it continues to rise beyond the duration of the effort. As such it is still rising when resting, at some point it will start to decline again, but by then another effort has arrived to push HR up, this will go on until HR near stabilises and depending on the frequency, duration and magnitude of the bursts of power, the value it stabilises around could indeed be quite high, like in the video.
 
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Power is the product of cadence and torque. So other than knowing that for a cadence of zero, power is zero, you can not expect to know power for any other cadence value since you have no clue as to the torque, which is what that power meter is measuring.
Thats watt (haha!) a power meter measures though, torque and cadence. Done by different methods by different manufacturers, Powertap use a hubt affair, Garmin has a pickup on the crank (I would think it's a strain gauge type measure) and one outfit uses a plate under your shoe. Cadence is easy.
Seems to be debate as to best way of measuring power and it's very expensive to do.
 

Rob3rt

Man or Moose!
Location
Manchester
Thats watt (haha!) a power meter measures though, torque and cadence. Done by different methods by different manufacturers, Powertap use a hubt affair, Garmin has a pickup on the crank (I would think it's a strain gauge type measure) and one outfit uses a plate under your shoe. Cadence is easy.
Seems to be debate as to best way of measuring power and it's very expensive to do.
I am well aware of that (having trained and raced using a power meter for several years now). The point I was making, was in response to User9609 asking/observing that other than when at a cadence = zero, power = zero there was no observable trend between the riders power value and his cadence in the video.

All reasonable power measuring devices use strain gauges to measure torque, regardless of where they are placed. The Garmin system is placed in the pedal spindle, the ugly pod on the end of the crank houses the other electronics.
 
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