CHAPTER X.

CRANKS, PEDALS AND AXLES.

Second only in importance to the bearings, sprockets and chain of the modern bicycle, as affecting the smooth running qualities of the machine, are the axles, cranks and pedals. Many have been the changes and rapid the march of improvement in these points within the past three years, until, with the advent of the season of 1898, there seems little that is desirable left for attainment in this direction.

“The hub is composed of two parts, viz., the axle and the collars or flanges. The former is a stout bar of iron or steel, forming the true centre of the wheel. It varies from ½ inch to 1 inch in thickness, and should not be less than 10 inches in length. The collars are circular plates of metal, varying in thickness from 3/16 to ½ inch at the edges and from ¾ inch to 2 inches in the centre. These are firmly secured to the axle by different methods. In some makes both collars and axle are one solid piece; but most are constructed separately, and are firmly united by brazing, increased facilities being thereby obtained for case-hardening the axle. For nutted spokes the collars are generally of steel or iron, wide at the edges in order to take the width of the nipple; out when direct-action spokes are used they are usually of gun-metal or brass (some few use steel), thin at the edges and gradually spreading out inward until they reach the axle. This is in order to give a large surface against the axle, as, unless a firm hold is obtained and the brazing well done, they are apt to work loose. These gun-metal flanges have, or ought to have, the exterior lower portion recessed to the depth of about ¼ inch, the indentations extending some 1½ inches around the axle, and the holes for the spokes drilled right through. By this a little weight is saved, and the spokes may easily be tapped out in case of breakage on the worm and a portion remaining in the hub. The pedals are thus brought closer together without decreasing the distance between the flanges, which should never, unless on very small wheels, be less than six inches apart, as, with a less amount of ‘dish,’ as it is called, the wheel is liable to buckle. The hubs for the back wheel are usually constructed solid, of either steel, iron or gun-metal, but occasionally they are complex. They are hollow, simply having a hole drilled longitudinally through them for the reception of the back wheel pin. If composed of gun-metal or brass, they should have a steel core to receive the friction, or they will soon wear out.”

This extract is given complete because it so well describes the regular construction at wheel centres twenty years ago. The gun-metal flange, ordinarily written in English catalogues as “gum hubs,” long ago disappeared; the back wheel, and the non-driven hub of early “safeties” were gum, with the bearing cups pressed into the ends, much as in the present fashion. The driven hub was fastened to the steel axle by “sweating,” aided by a key driven in flush between. In this country the G M hub did not prevail. The Columbia front hub, for example, comes up before the mental eye—a great spool of excessive strength and weight, both threaded and pinned on, so that parting from the axle was not to be thought of. In the present type the driving axle is a third, independent of the wheels, and the wheel hubs are either turned from the solid steel bar or drop-forged from steel, or formed from steel tube, the “bike metal” casting being kept very quiet in this as in other portions, or else reserved for the people who suggest that the cheapest way to procure a bicycle is to buy ready made parts and “build” one’s own.

THE “DIVIDED AXLE.”

(See Page 93.)

Cranks were sometimes shrunk on, sometimes threaded on, and sometimes held on by wedging keys. Of the many ways, the survivors are the transverse key known now as the plain “cotter pin and nut,” and the D-shaped end, the latter being sometimes made like a square with three corners rounded, as recently on the Wolff-American and Remington, for example. A shape quite in vogue now is a tapered round, with one or two sides shaved to a flat and also tapered. Up to the time of the last Garden Show, two years ago, axles had been made in one piece, and the separate cranks had been attached in some of these above-mentioned ways, with a very few exceptions. It may also be said that this was the most ordinary and obvious mode of construction. But at that show appeared a very simple and good specimen of divided axle, the Gard, although not the first, for the Columbia had been trying the idea for a year or two, and had set the fashion. For some reason the Gard axle—which was joined at the centre by mortice-and-tenon, each half axle being one piece with its corresponding crank—has not gone much into use. This is probably because makers have desired to have devices of their own; at least, there has since that time been a raging epidemic of “divided axle.” It is quite within bounds to say that at least a page of this journal would be required to intelligently describe and illustrate the manifold devices of perverted and costly ingenuity for cutting the crank axle into two parts and then sticking the sundered parts together again. There are axles cut on single-tenon and on double-tenon; axles with straight bevel, zig-zag bevel, circular-notch lap, and with a long “skived” lap, as if glueing were proposed and a lot of surface were required for a joint; there are sleeves threaded and sleeves not threaded; there are halved hollow axles, to be held together by a screw bolt lengthwise through them. Some of these may perhaps have fallen, together with the makes of which they were a part, in the conflict of last season, but mostly they are still extant. Generally, the division is at or near the centre, but sometimes it is well at one side, thus approaching a more reasonable and quite common form which has axle and one crank in one piece and attaches to them the other crank removably. It is admitted that occasion to remove a crank may occur, and the wearing strain and exposure to dirt are so great on the present crank bracket that some device for detachability is almost necessary; yet only the seeking for peculiarity and the feeling on the part of designers that they must appear to be earning their pay can account for these constructional frenzies which it is not practicable to describe in detail. Here we may say that the Humber still adheres to the ancient and substantial device of separable cranks, held on by the transverse “cotter pin.”

STRICT “ONE-PIECE” CONSTRUCTION.

In strong contrast with this may be mentioned the Fauber one-piece construction, by which both the cranks and the axle are made of a single piece, being passed into place endwise into the open bracket, the bearing parts and fastenings being next put on and finally the pedals. This patent is a radical departure in the direction of extreme simplicity and strength, having obviously no chances of getting loose and giving the desired absence of nuts and projections about the bracket ends. It seems to be steadily working its way into use, and it may be easily recognized by the “star” sprocket, which is commonly used, in connection with it, although not a necessary part of it.

Heinz & Munschaur of Buffalo, working under a license from Fauber and some pending patent of their own, describe their own one-piece construction as being from steel of high carbon, and say they will replace any which may be broken from any cause whatever. They fasten the spider to the crank mechanically, not by brazing; the sprocket rim is firmly held, but is readily detachable; the ball cases contain fifteen 5/16 balls with retainers, “and fit to a shoulder in the hanger, doing away with any threads, which are liable to give trouble.”

Among makers using the Fauber construction are the Winton, World, Defender, Fenton, Outing and Union (the last-named on their special).

CRANK THROW AND VARIABLE GEAR.

The crank, like the axle and most other parts, used to be very thick and heavy. As the quality of steel was improved and a more exact knowledge was obtained of the relative strength required through the parts of the structure, the metal was gradually pared away; in fact, there could be no better object lesson of bicycle evolution as a problem in mechanical work than to compare, side by side, the axles, cranks, hubs and pedals of today with those used in 1878. The old slot for variation of crank throw, sometimes replaced by three holes, disappeared from the crank long ago. Right here we might say—without stopping to consider the topic at my length, because it is not at present in agitation—that two-speed or three-speed gear and variable pedal stroke, while a tempting subject for inventors, are not and never can be really practical in the complete sense. To exchange power for speed or vice versa at will, so that one may vary his “gear ratio” to suit surface and circumstances, is indeed desirable; it is not in question that if one could drive the driving-wheel as fifty or as 120 or as anything between at pleasure it would be a consummation devoutly to be wished—but this cannot be done. If lever-driving is used, which is the most manageable mode for this particular object, a variable leverage can be obtained; but the offsetting disadvantages, which are not small, must be accepted too. As for shifting gears, they allow only two speeds, and it is not wholly easy to decide in advance what two are on the whole best; when the choice has been made one is sure to want more than two and almost sure to be as little satisfied as before. Moreover, the weight, complication, wear and cost of these devices are obstacles which must ever bar them out.

CRANK DROP AND CRANK THROW.

There seems to be some disposition to substitute “what is the drop” for the recent question “what does it weigh?” It is not certain that most people understand that “drop” means anything more than a lowering of the crank-hanger and a relatively slight lowering of centre of gravity; it does in fact mean more. The drop is the lowering of the crank axle below a line drawn between the two wheel axles. This line is fourteen inches from the ground. If one will stop to consider that from this must be taken, in use, the drop of axle, the crank throw, the dip of pedal below its own pivot, and the further dip of the toe-clip which no strictly up-to-date scorcher can omit without endangering his caste, he will see that to combine (as some wish and propose to do) a 3-inch drop with a 7-inch crank is to invite disaster. Not more than a single inch of clearance from the ground remains. This inch is as good as a yard while it lasts, but can anybody carry it in his pocket and thus make sure of always having it? There is the inclination on curves, and ruts and stones may be encountered, even if riding is confined strictly to the asphalt.

The length of crank throw is periodically discussed, and there is a disposition to jump to the conclusion that excessively high gear ratios may be made easy by increasing throw to 7 or 8 or even to 8½ inches. We do not think it worth while to go into this discussion at present, but will state five propositions: 1. The customary crank throw, like the size of wheel and some other factors, has not been obtained arbitrarily, but as a compromise between opposing considerations. 2. The labor of high gears is not thus easily disposed of, because the increased leverage involves a longer circle of travel, a change in the position of seat relative to pedal, and different angles in the muscular action. 3. The throw is closely related to the length of argument set up by some that proper crank upper and lower leg and the length of foot is fanciful rather than sound. 4. The question of crank throw, like that of vertical or forward thrust, must be counted among individual matters and is not to be disposed of by the dictum of any one person set up against the rest of mankind. 5. A long crank is, however, positively wrong for use by women, because it increases the high rise of the knee which, for them, is so ungraceful and is both mechanically and hygienically wrong.

GEAR RATIO.

This is a proper place to explain gear ratio or “gear,” which is a phrase not generally well understood, although in constant use; for instance, women have been known to ask dealers for a wheel with low gear, because they liked to be seated near the ground. The term gear, which is an adaptation from the old high wheel, expresses the ratio of forward travel of the bicycle for each pedal revolution, and yet this has nothing to do with either the height of the rider or the length of his leg, or the length of the crank. It depends—with a given size of wheel—solely on the relative size of the two sprockets, as measured by the number of their teeth. For example, if the front sprocket has 20 teeth and the rear has 8, it is plain that each tooth of the former will pull a tooth of the latter; so when the former has made one turn it has pulled 20 teeth on the latter, thus causing the rear sprocket and wheel to make two and a half revolutions; as two and a half times 28 are 70, we say that a bicycle with such sprockets has a 70 gear, meaning that one revolution of the pedal drives it as far as one pedal revolution would drive a wheel actually 70 inches in diameter.

Computation of this ratio is by the rule of three. Thus as the number of teeth in the small sprocket is to the number in the large one, so is the actual to the equivalent or running diameter of the wheel. Multiply the wheel diameter in inches by the number of teeth in the large sprocket, and divide the product by the number in the small one. Or, for each size of rear sprocket, multiply the number of teeth in the front one by a certain number (which is a constant factor) and the result is the gear. Thus, if the rear sprocket has 7 teeth, multiply by four; if it has 8 multiply by three and a half; if it has 9 multiply by three and one-ninth; if it has 10, multiply by two and four-fifths; if it has 11, multiply by two and six-elevenths; if it has 12, multiply by two and one-third. This is for a twenty-eight-inch wheel; other sizes require slightly different factors.

For a bevel-gear chainless the method is to multiply the number of teeth in the crank-shaft gear by the number in the rear pinion on the shaft and multiply this product by the number of inches of diameter of the rear wheel; then divide this product by the product of multiplying the number on the wheel hub by the number on the forward pinion on the shaft.

SHAPES OF CRANK AND SPROCKET.

The original crank or rectangular section has for some years been generally round, or of an elliptical section tapering to round at its slightest portion at the end; a few makers have used a bayonet section, or have chamfered out the inner side; fluted sections have also been used, and one or two have brought out a crank in the shape of an S, in the not well-founded notion that it is a good point to depart from rigidity in the driving, or perhaps imagining that a longer throw is thus obtained in the effective portion of the stroke. But there is now a decided reversion to the rectangular and even to the tapered square crank; cranks of bayonet or flattened diamond section are also quite in vogue, notably on the Fauber one-piece construction. There does not seem any considerable reason for choice between round and square, on the score of strength, but the round should hold nickel better, which always shows an inclination to peel on an edge. Still another shape may be mentioned, which has some novelty and neatness—a square or rectangular crank that smooths off into round a few inches from the axle.

Although not new this year, we may mention the peculiar Victor reversal of usual construction by putting the axle on the crank, so to speak, instead of the crank on the axle; the axle is hollow, and the crank stands through instead of over its end. The Spalding crank has on its end a lug or boss which fits a sort of heart-shaped end on the axle, the crank proper being very slightly outside the line of the axle instead of exactly across that.

The Racycle continues its well known peculiarity of putting the bearings of the crank axle within the crank ends, so as to increase the distance between the two ball rows and bring the line of chain pull between them. The Cleveland has a similar arrangement for the same purpose.

There is a disposition to return to the fixed front sprocket in a single piece, as was the construction before the central “spider” with a removable rim attached came into use. The spider itself has been strong enough, but the portions to which its arms were screwed and the rim itself have been rather slight of late, and the toothed rim has not always had support enough. There has therefore been a liability in the sprocket to spring under strain or even to take a “set” out of line, and the change is to be approved on the whole, especially as a very easy detachability in the front sprocket is rather a “talking point” than otherwise, since it is rare that any rider avails himself of it in order to make a change of gear ratio.

Hewitt Brothers, of Cumberland, Md., have a form of sprocket in which the central portion, which comprises the whole except a rim just large enough to have the teeth on it, remains fast and immovable on the crank bracket. This rim, being coned on its inside edge to match a coned recess on the outer edge of the fixed central portion, has a row of balls between and runs around on those balls, just as the intermediate spur gear wheel does on the Hildick chainless, already described and illustrated. For this sprocket device the usual claim is made that it so increases ease of movement that a gear of 120 with it requires no more power to drive than one of 70 without it.

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.

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.

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.

THE RAMSEY SWINGING PEDAL.

(See Pages 90 and 91.)

The usual pedal has its tread above the pivotal point; the Ramsey pedal reverses this and always has the tread below that point. Its great claim is that “it transmits automatically, in conformity with the arc of the circle described by the pedal, the applied power of the rider, thus maintaining the full leverage of the crank over a vastly increased arc of the circle; in other words, it converts the straight push into an improved and automatic ankle motion and renders possible a higher development of foot power than has hitherto been obtained.” The ingenious “clock” diagrams, the circle being cut into twelve divisions representing hours and of 30 degrees each, illustrate this. As the inventor is pleading his own cause it need not be counted against him that he unconsciously exaggerates the foot positions somewhat, and when he says that a continual pressure may be applied “from 11.30 to 8, or 8½ hours out of 12,” our comment is that we think it possible for a good rider who pays attention to doing it to apply pressure thus on the usual pedal. But the difference is that the Ramsey gives a better hold to the foot, thus applying mere pressure instead of merely “some” pressure, and makes the ankling semi-unconscious and automatic; this forms a substantial improvement, and, as the inventor puts it, “it gives ankle motion where there was none before, and those who ankled some now ankle more.”

Incidentally, the twitch which many riders give to the chain slack by incorrect pedalling is more easily avoided with this pedal, and, of course, there is less trouble about being “caught on the centre,” hence hill climbing and control in crowded places are favored; as one trouble with a high gear is in passing over the centre at slow speed, the Ramsey pedal has an advantage in control for this reason. The “pick-up,” either when mounting or when quickly spurting ahead, is also particularly good with it. Another peculiarity of this remarkable pedal is that its tread is as much below the pivot at the top as at the bottom, so that the leg reach is increased near the ground and decreased at the top. This will be valued in practice, according as the riders find it comfortable to drive (as does the writer) with a full leg reach, or not; yet it is plain that the Ramsey must be a very desirable pedal for women, because it decreases the objectionable rise of the knee.

The construction is clearly shown in the cut. A removable screw replaces the usual pedal shaft, and the pedal will fit any wheel, but it requires lowering the saddle or using a lower frame, and it therefore rather strikingly suits the present fad for reduced frame heights. Although a single row of balls has to be used, they are one-quarter inch, eighteen in number, and two-thirds are claimed to be always under pressure. As to durability, the inventor says that after some thousand miles’ use under average conditions, the nickel on the cones has been found intact; this must be explained by the large number and size of the balls, the large diameter of their track, the correct construction of the bearing (which is a four-point of right-angled V section), and the complete exclusion of dirt and retention of oil. In the last particular nothing could be more perfect.

After careful practical test, we think the inventor’s claims are well sustained. The Ramsey pedal is certainly fast, and distinctly good on hills. Other conditions being equal, it should beat the ordinary pedal in pace and endurance, and we regard it as one of the most practical contributions of the season.