Quote:
Originally Posted by kramnnim
In the pedaling situation that I keep mentioning, where the rider is out of the saddle, rocking the bike with his or her arms, 60rpm or so- I think the frame flexes between 2 and 5 oclock, taking torque/rotational force from the rider. The frame flexes back at 6 oclock, and I don't think it helps the crank arm rotate. Sure, the riders foot may go upwards, but it took away a fraction of a degree of rotation, and did not give it back. So I think that energy was wasted.
...I tested this for myself yesterday with a Pioneer power meter+head unit and there's no force shown at 7 oclock. At 8, it shows me pulling up.
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"Upwards" as in pro-spin or anti-spin. If it is pro-spin, then it is putting energy back into the drivetrain.
Quote:
Originally Posted by kramnnim
I've also mentioned the full suspension bike with no lockout several times. The suspension compressing can easily take away downward force that could go towards rotating the cranks. When the suspension rebounds, yes, the rider's foot will move upwards, but it will not help rotate the cranks.
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Rear suspension has always been known to waste energy to a degree and most systems have tried to combat that by putting the pivot along the same line as the tensioned chain. But that has nothing to do with what a rigid rear end does when it twists - completely different beasts.