Why is he testing with such long crank arms? I mean 177,5, 180, 200mm. He's a tall guy but unless you happen to be a giant..
In all cases, I rode as hard as I could go. Of course, some days are always going to be better than others, and multiple runs are required to see any kind of a trend. [For those wondering why I didn’t use a power meter, holding a given power output (which would have had to have been measured in the hub rather than in the crank or pedal for obvious reasons) would result in the same time on the climb. Or, measuring average power output or total work done when going full out should have resulted in the same relative results on a steep climb without significant wind.]
Too right. Qualitative human power using a mechanical process is limited to interface of hardware. That's to say hardware will give reading limited to its sensor capabilities. If there is a mechanical advantage the power reading won't take into account. Mechanical measuring doesn't calculate precise internal physiological work/power expenditure. Only relative.
On the upstroke, due to the foot pointing down, it is close to following the same trajectory as with the 180mm crank. The illustration here compares a 190mm Zencranks crankset with a 15mm link arm to a 175mm standard crank, a scaled-down version of what the 200mm with a 20mm link compared to a 180mm standard crank would look like. Because the foot comes up so high, there is an increase in the gravitational kinetic drop of the mass of the foot, leg, and pedal. Zani claims that the cost of lifting the foot that high does not counteract the gain from dropping it.
This statement is extremely dubious.
The chainwheel has the pedal attached offset to the bearing using a pivot. The bearing is in chainwheel arm.
The motion of orbital path of pedal stroke produces a trilate, not an egg shape. I have created proof of principle to show this. I used minor variables to exemplify size of pivot (which offsets the pedal).
Clearly it is seen, the trilate has a longer trajectory from 12-6 o'clock position. This is Shimano's hypothesis for power optimization at delivery. Then there is a relatively shorter up-stroke. Also dead-center is offset to part of the up-stroke leaving more for down-stroke after 12 o'clock position.
What we see overall clearance is decreased. it's like running longer chainwheels on your bike.