EVOLUTION OF THE PEDAL.
The old pedal was two elliptical disks of sheet steel, joined in the centre by a tube to pass over the pedal shaft, and having two round rubbers for the tread, on rods which were riveted into the ends of the side plates. The bearing was either plain or the wretched “adjustable cone” already described. Later, corrugated or ovoid rubbers came in; still later, the sensible “square rubber,” for which the Overman people may claim the credit. The same pedals went on the early rear-driving “safeties,” for those not only followed the manner of the high bicycle in general construction as far as could be done, but utilized its actual parts considerably. Probably in the process of paring off ounces of weight, the fixed rubber, of whatever shape, disappeared from the pedal; the serrated-edged or “rat-trap,” which used to be thought fit only for the race track, took possession, and rubber is to this day used only in the form of light and removable slips. These have commonly been of a section like two T’s set end to end, the flat portion being on the inner sides of the tread plates and the roughened T sides forming the rest for the foot. The Wolff-American now offers slips of a triangular section, four for each pedal, which are held by a sheet steel clip screwed on the side plates, and have three edges each, so that they can be turned in their seats to present a fresh surface until worn out. The Straus removable rubber is also simple and practical; it can be slipped over the pedal plate or removed at will, without need of tools, and another form of it can also be slipped over the outer ends of the pedal to take any blow from falls. It does not interfere with a toe-clip.
The pedal shaft grew more slender with other portions. The early ball pedals, by a strange slip backward, were made without a tube to connect the bearings and keep off dirt from the foot, nor did this bad method quite disappear until about a year ago. A recent bad construction which has not yet wholly gone out is the very thin connecting arm and the very light side plate, the whole put together so poorly as to be liable to twist. This has been dubbed the “tin pedal,” and there are pedals today, even on some well-known makes, which have too much of this characteristic. The Wolff-American pedal of 1898 is an example of what a pedal should be in point of quality of steel used and firmness and durability of construction; yet this is not mentioned as if it were the only praise-worthy one, but only as a good example of high quality which comes to mind. No very low-priced bicycle can be found in market with such quality running through it.
The most decisive step in pedal improvement was the appearance of the Record type, patented by A. C. Davison, an Englishman, consisting essentially of a central core with two cross-arms thereon, drop-forged in one piece. This secures strength and permanent alignment of the bearings, and a single piece of spring steel is brought around to form the tread. As now made, this continuous plate itself forms an end to take any blows from side falls and a guard to keep the foot from slipping off. So long as the pedal remains two faced and rotary it is hard to conceive how this can be materially bettered. It is a long step from the original pedal of thirty years ago to the light but strong one of 1898. The earliest one was a round spool; then triangular in section; then improved by having a balance weight of acorn shape hung below to keep it presented to the foot. In lever-driven bicycles it was a plain flat top, as on the American Star, or a round rubber-covered bar, as on the Facile.
WOLFF-AMERICAN
CRANK AXLE.
The early fastening to the crank was the natural large nut, screwed up against the inner side of the crank. Demand for reduction of tread abolished this in favor of the now almost invariable method of simply screwing into the crank. But the use of right and left hand threads for this ought to be discontinued. In effect, the pedal revolves toward the rear wheel, so that, in theory, if the bearing should bind there would be a tendency to turn the pedal shaft in that same direction within the crank end; to meet this, the right pedal crank was tapped with a left hand thread, so that the revolution of the pedal might always tend to screw the pedal shaft in and not out. But experience has quite satisfied us that if a pedal loosens (as it not infrequently does) it is as often one as the other, and the reason is that the force which loosens is not the tendency of the pedal to carry the shaft with it, but the downward pressure coming on the shaft itself. If, therefore, the fit of thread between shaft and crank is good, and if the shaft is screwed firmly home, and if (very particularly) the outer edge of the hole in the crank is turned out so as to allow the pedal shaft’s being driven close up against the face of the crank, nothing more can be done to prevent loosening, nor need anything be. The objection to making a left hand thread on one pedal is that by this common method each pedal must have its own shaft; this bothers dealers and repairers, and if a rider about to take a long tour wants to provide against the chance of a break here by carrying a spare pedal shaft he must carry two instead of one. Simplicity, uniformity and convenience would gain by making all pedals and cranks with right hand threads.