ANKLE MOTION IN PEDALLING.
The early pedal already mentioned, consisting of a round spool on a plain wagon bolt, with an outside nut, preceded any knowledge of “ankle motion,” or rather, it might be said, the extreme forward thrust then made necessary by the position of the rider with reference to the pedal made ankle motion impossible; the thrust was with the sole of the foot and the heel came against the spool as a stop against pushing off. The Ramsey swinging pedal—or, as the inventor prefers to call it, the under-swinging pedal—is the farthest possible departure from the original pedal, its sole suggestion of old-time devices being that it always keeps itself in the position of presentation for the foot, because the weight hangs below the centre, as on the balance weight pattern of 1869. The Ramsey can never be caught by the foot on the edge, as the usual pedal so often is when mounting; even if the toe-clip (which seems less necessary with this pedal) is insisted on, it is readily attached and still the tread surfaces remain horizontal and ready for the foot. But these are comparatively trifling matters; the claims for this pedal relate to ankling and a more favorable use of the crank leverage.
When a crank is turned by a mere reciprocal or back-and-forth movement, the radius or leverage of the crank is constantly varying from full length to zero and back again; the zero position is called “dead centre,” because all power applied at that point is pushing upon the axle and has no tendency to rotate the crank. If the hollow of the foot is placed on a pedal, so that the line of thrust is directly in line with the lower leg, the calf muscles do no work and the thrust is a straight leg-thrust, as if the foot were lacking or the leg were wood; the same result would be obtained if the ankle joint were anchylosed or if the rider habitually maintained his foot at a right angle to the lower leg—in each of these cases there would be no ankle motion whatever. Here we may remark that although lever-driving has its claims its worst defect is that very little ankle motion is possible when the fulcrum is a swinging one and when the fulcrum is stationary there can be none at all. In turning a grindstone with the hand, the crank is easily followed around the circle and thus the full leverage of the crank is used (subject to some disadvantage from the position of the arm) all the way around. If we could clasp our toes about the pedal—as the evolutionists say our ancestors clasped theirs about tree branches—we might pull the pedal clear around. Ankling, as it is called, consists in alternately raising and dropping the heel so as to give the foot some hold on the pedal, and then in pushing forward or “clawing” backward, so as to apply some power during the greater part of the circle, instead of merely shoving down on the pedal after it has passed the upper centre. The more this can be done the more nearly the full leverage of the crank is retained and the more nearly “dead centre” is abolished.
Constant and uniform application of power—that is to say, effective application—largely depends on this. For example, the writer (who counts himself not more than up to good average as to ankling) can climb a pretty fair grade, on a good surface, with only the forward push over the upper centre. Of course, people differ in pedalling, as in other features of riding, but ankle motion must be deemed one of the best tests of correct pedalling and therefore of good riding; it is no fad, but in the utmost degree practical, and whatever contributes to it is, so far, valuable.
GARD CRANK AND DIVIDED AXLE.