How Is Torque Effectiveness Calculated by Vectors 3

According the formula on the Garmin web page, the Torque Effectiveness is calculated as (((P+) + (P-))/(P+))*100. If I understand right, this sum of ((P+) + (P-)) means the total power or work applied to the pedal, and the P+ is the amount of the power applied effective in the relationship of the movement of the bike.

If it is supposed to be as is written above, than the relationship is probably not correct and should be replaced by ((P+)/((P+) + (P-)))*100.

The other question is - if the Vectors 3 evaluate the effective force acting to the pedal compare to the total force. Because only the vector of the total force acting perpendicular to the crank arm is effective and causes movement of the bike, rest of the force is wasting of the energy.

Do the Vectors 3 evaluate the pushing down also pulling up of the pedals to result the total power and the cycling dynamics? I suppose yes, but I did not find the clear information.

What values of Torque Effectiveness is supposed to get for the unloaded pedal, when I am using Vectors 3 (dual system) in case of:

I am pedaling only with right foot, the left foot is out of the pedal

I am pedaling only with left foot, the right foot is out of the pedal

Testing my Vectors 3 I got different values for the unloaded pedals, I got for unloaded left food value of 99 and for unloaded right food I got 0. In both cases acts on the unloaded side only the self-weight of the pedal, probably the results should be the same...

Kind regards.

milos

0 t_smit over 4 years ago

1. The Torque effectiveness value gives insight into how well you might be "pulling up" on the rising part of the pedal stroke. In the equation given, P+ denotes the total of the positive torque samples in a given pedal stroke, typically generated on the downstroke, and P- denotes the total of the negative torque samples (which is a negative value). The net work done through the whole pedal stroke is the sum of the positive and negative torques, ((P+) + (P-)). The torque effectiveness, then, is the net torque divided by the positive torque. This will always be less than 100%, unless the negative torque is zero.

2. The Vector spindles can sense force in any direction, and use an internal determination of how the spindle is installed in the crank (the "installation angle") to calculate the perpendicular component, which is then used to determine the torque through the pedal stroke.

3. Yes, the pedals sense torque in both a positive and negative direction.

4. The loaded foot will typically achieve a torque effectiveness of 100% because it has to drive the crank all the way around, thus there will be negligible, or zero, negative torque. The unloaded foot may report unexpected numbers because the numerator and denominator are both very small, and the pedal weight itself will cause some small torques to be measured even when the foot is not on the pedal.

0 Milos Slivansky over 4 years ago in reply to t_smit

Thank You for the clarification.

1. If the P- is in the relationship negative value, is clear to me now. I supposed, the absolute values are used.

2. It is a pity there is no such a result in cycling dynamics as a force effectiveness, where the ratio between the total force (used energy) and efffective force (energy effective for the movement) could be obvious. I think it will be not the same as the Torque effectiveness and it could be also helpful for deeper analysis.

3. OK

4. Are you sure the loaded foot will achieve always a torque effectiveness of 100%, when one foot pedaling is used? Does it mean, that the negative torque values are always caused be the unharmonized movement of the other foot? I thougt the pedaling could be theorethically ineffective in case of one foot is used, because movement of your foot could be imperfect in the relationship to the optimal pedaling (maybe it has something deal with I wrote in the point 2.)

I understand, the unloaded side is strongly affected by the inaccuracies caused by the small values of the force acting on the pedal, but 99 percent compare to 0 percent is dramatically different.

m.s.