what is the unit of measure for PM calibration?
Just out of curiosity: When I calibrate my Quarf at home, it shows calibration of "94". This morning, when I calibrated it in my parents' basement, it showed "100". I think this has something to do with temperature etc, but what exactly is the PM calibrating against? Thanks!
0
Comments
100-94=6
6/32=.1875 Nm change
FWIW - my Quarq is always within 10 of 580 before, during and after rides.
Thanks Dino. I didn't realize I had to calibrate post-ride as well. And of course, I promptly forgot to do so this morning... Will try to remember next week. thanks
What you can do is zero the the unit every hour or so by pedaling backwards 6 times. This is helpful if while coasting the unit shows 1 watt or something similar. Back pedaling tells the unit what zero is.
I learned most of this thanks to our good friend, Bob, above. He turned me on to a great resource on the Quarq site. They have a forum there where guys are FREAKiNG OUT about the smallest stuff. It's fun.
I am not an expert by any stretch. If I have missed any technical nuance, other please chime in.
Thanks guys. EN is teaching a little something new every day!
""""" Just out of curiosity: When I calibrate my Quarf at home""""". I don't know about calibrating a Quarf, but the correct metric is NEWTON Meter, not nano meter. Na nu, na nu.
I would think this is correct, as N·m is a unit of torque, whereas nm is nanometer - a unit of distance. However, I could certainly see where the dot gets dropped easily, leading to Nm, and then the correlation of Nm to nanometer.
It is Newton meter. I have no idea why I typed nanometer unless it was an autocorrect by my iPad. I've never even said nanometer, much less thought it.
meter = distance
Newton x meter = Joule : energy
Joules (energy) are not the same as torque
Torque is the angular analog of force, technically defined as Force x radius (from pivot center) x sin (angle between force and radius).
If you assume the force is perpendicular to the radius, the sin of that angle is of course 1. If you apply the force straight down into the radius (e.g., the crank arm), however, common sense suggests that you don't rotate the cranks, and sin of the angle of 0 = 0.
Experientially, Torque is how hard you are pushing the pedals, Energy (Joules) is the total amount of work done, no matter how long it takes to do it, and Watts is how much energy you are expending per unit time. (1 W = 1 J/s)
Funny! Kate said Quarf, even funnier!
Hey! English is my second language!! Ok, ok, that does not excuse poor typing, I know.,.Btw, the German translation of "Quarq" (as pronounced, not spelled) is "Greek Yoghurt"...
Just to satisfy my own curiosity, and figure out the disconnect (I nitpick like this sometimes) - help me figure this out. Unfortunately I've gotten rid of my college physics books, leaving me with stuff like wiki and the web.
As I understand it:
In the SI system, a joule is defined as the work of moving 1 meter against a force of 1 newton. So, as you mention, the product of NxM is a unit of energy.
However, the resultant torque of a force of 1 newton at a (perpendicular) distance of 1 meter is also a newton-meter.
While they have the same units, the difference is that torque includes an angular component (sin) whereas energy is force through a (straight) distance.