Originally Posted by
FBinNY
Not true. If the foot and pedal stay horizontal throughout the stroke it doesn't in any ay change effective crank length which is fixed by the distance separating the bearings. What it does is raise the foot position at all places in the circle, exactly the way children's pedal blocks do.
The maker's claim that length changes because the foot is angled seems more complex, because there's a compound lever, but essentially is the same. However it has a major drawback of creating a pedal torque which increases stress on the foot and ankle. This is probably minor if the foot stays level and above the bearing, but increases as the foot is angled and the force is applied forward of top-dead-center.
No matter how you slice it, this is another L-shaped crank, and insults previous attempts to improve the bio-mechanics, such bio-pace, power cm and others which at least had some merit.
You said my post want true but they your evidence supported it.
with the foot horizontal it doesn't change the crank lenght (190mm) on the front of the stroke at all. This is exactly what their own diagram shows. The effective crank lenght is 190mm and the actual crank lenght is 190mm...
at the bottom of the pedal stroke (foot horizontal) the block reduces the crank length. See math on diagram.
the only "complex angle" they suggest is at the back of the stroke where it again reduces the crank lenght from 190 to about 175mm
the only difference between this, and pedal blocks is increased pedal clearance. It isn't a performance enhancer, it is a way to use longer arms 190 vs 175 without pedal strike concerns. Anything more is a gross over complication.
it shares nothing with L shaped cranks. The bb spindle to pedal distance (effective lever) is constant with an L shaped crank. These have a variable lever lenght. It matches the crank lenght on the power stroke, and it shrinks it for pedal clearance at the bottom.