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.”

[Illustration: EXTENSION PEDAL—AMERICAN WALTHAM.]

[Illustration: AMERICAN WALTHAM PEDAL.]

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.”

[Illustration: STRAUS REMOVABLE PEDAL RUBBERS.]

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.

[Illustration: THE RAMSEY PEDAL.]

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.

[Illustration: “CLOCK” DIAGRAM—ORDINARY PEDAL.]

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.

[Illustration: “CLOCK” DIAGRAM—RAMSEY PEDAL.]

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.

[Illustration: 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.

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.

[Illustration: GARD CRANK AND DIVIDED AXLE.]

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.

[Illustration]

The Modern Bicycle and Its Accessories · 第 10 / 17 章