THE MODERN ROVER, OR REAR-DRIVING SAFETY.
As machines of this general type bid fair to engage the attention of
cyclists to a marked degree, it seems in place to give them more than
a passing notice in the general discussion. It is fair to presume that
more than one-half of all the machines sold in the immediate future
will be more or less after this general pattern.
The introduction of the Rover has afforded us one of the most amusing
incidents in cycling history. The writer of these pages happened to
be in Coventry during the summer of ’85, and he had a fortuitous
opportunity, fondly accepted, of inventing fun at the expense of the
“Crocodile” and of joining in the general laugh at the (alleged)
ridiculous attempt of a Coventry firm to “foist” (_sic_) this most
extraordinary freak of cycling inventive genius, under a new name, upon
the market.
In the fall of the same year a notable Washington agent, allured by the
attractive notices of a great prize for a hundred-mile race, imported
one of these self-same incongruous specimens into this country.
After a few weeks of hilarious humor, followed by a sullen contempt
for the thing, this Washingtonian shipped it to a great American
manufacturer, who made sport over it for a year or two before we all
began to scramble around and make ready to prove that each one of us
individually “saw it all the time.” It has been a hard pull, however,
and it is still uncertain on whom it did first begin to dawn that
somebody had been guilty of colossal stupidity.
One thing the Rover accomplishes, previously touched upon, is the
location of the rider as nearly over the work as he chooses to be;
which has been the end and aim of all our efforts in that direction.
Had this machine been offered to the public, in good shape, at the end
of the old bone-shaker _régime_, it is questionable if the Ordinary
would ever have acquired the prominence it did. In early times,
when learning to ride a tall machine was considered quite a feat of
gymnastic exercise, such as only the young and sprightly could ever
perform, many, who afterwards by force of circumstances did accomplish
the feat, would never have tried it if there had been anything else,
such as the present Safety, to learn upon. Every accident on the
Ordinary would have told heavily against it in the market, and every
severe casualty would have made a new Safety rider; as it was, however,
there was only one of three things to do,—take to a three-track
machine, stop riding, or try the old mount again. It is needless to say
that, almost to a man, the last condition was accepted, and the result
is that now we have a class of men who can handle an Ordinary with such
dexterity that many of them conscientiously aver that there can be
nothing safer. However, among those most devoted to it at the present
time there are few, if any, of the close observers who would have
stood sponsor for their favorite machine had the rear-driver made its
appearance in its present form prior to the advent of the Ordinary. To
say that the latter would ever have obtained a footing above the level
of a fad or a curiosity, would be equal to denying that the Safety will
now ever hold an enviable place among us.
In the minds of many the sprocket-wheels and chain stood much against
the introduction of the rear-driver; true, many good tricycles were
implanted firmly on the market with such devices for conveying power
to its necessary locality, but there was always such a vast chasm
lying between the single- and double-track machines that riders did
not care to get down to minute details of differences. To an Ordinary
rider the idea of sprocket-wheels was, and is yet, for that matter,
an abomination, only second to that of being dropped down from his
elevated position to the humble plane in which his fellow on the Safety
is wont to revel; but nothing in the way of change in the cycle art is
unbearable after we become accustomed to it.
No doubt the old Kangaroo, as bad a failure as it was, led us up
to endure more complacently the rear-driver in respect to the
sprocket-chain; yet in no type of machine could the subject have been
brought to our notice in a worse form. The tricycles using a single
chain did away with one of the great evils which appertain to this
system as found in the Kangaroo, in which we have two chains working
entirely independently. The evil of such an arrangement is easily seen:
no old Kangaroo rider, or rider of any other double-chain device, is
ignorant of the annoyance caused by reversing the slack in each at
every half-revolution of the pedal. Keep the chains ever so tight, this
slack will be felt as the pedal crosses the dead-centre line at the top
and the bottom. In spite of all this, some reputable makers persist in
constructing rear-drivers having the double chain, and as a matter of
course justly fail to meet with much approval from the riders thereof.
A word in regard to the nature of sprocket-wheels and chain. It is
perhaps not generally understood how important it is that they should
be well made, with especial view to resist stretching and alteration
of pitch, any tightening device, no matter how deftly made, being
an inconsistency in mechanics. To be sure, the spreading of the
wheel-centres cannot do much harm, and it saves some annoyance, but it
does not cure the real evil, nor is it any better to take a link out;
it is the length of each and every link that is wrong, and it can only
be cured by either changing each link or by altering the sizes of the
sprocket wheels.
Two gear-wheels cannot run properly together unless they are
proportional in size to the number of teeth. Now, the stretching of
a sprocket-chain alters the pitch in a manner similar to that of
retaining the same number of teeth in each of two intermeshing wheels,
and then altering the size of one. A sprocket-chain acts substantially
as an idle wheel; when it stretches we have, as it were, this idle
wheel made larger while the size of the others and the number of teeth
in each remain the same. Increasing the distance between the centres
does not affect the size of the wheels, and when a sprocket-chain
stretches or becomes longer by wear the wheels should either be larger
or else the number of teeth diminished. It is a general idea among
mechanics that chain gearing is about the most undesirable of all means
of transmitting power we have. This is perhaps an exaggeration, and
I think the cycle art has proved it to be so; but the idea no doubt
is fostered by this constant tendency of the chain to stretch, and
when this stretch takes place a very considerable amount of friction
must result. There is another annoyance felt by patrons of the small
wheel: the chains being low down and well oiled, as they should be,
especially if once they become stretched, have a superlative capacity
for accumulating and holding dirt, causing a grinding second only to
that of a finely-set quartz-crusher. This feature is not so much to be
deplored if the dirt can be kept out of the chain-link bearings, since
it is not the wear of the link against the tooth of the wheel, but that
within the link, which makes it longer, alters the pitch, and causes
great friction.
We shall, however, have to accept this chain arrangement for the
present in Safeties, as it cannot be helped. Some ingenious inventor
will no doubt ere long come to our assistance; but until then we can
tolerate it with a good grace, since it is a necessary concomitant of
so valuable an acquisition to our assortment of mounts.
There is apparently little difference in the construction of the crank
Rover Safeties, yet there is more than a cursory glance would lead us
to suspect. To begin with, there is quite a variation in the slant of
the neck or front fork, many makers giving a considerable curve to
the fork, thus throwing the neck much straighter up. Then we have the
telescope head, where the front fork revolves inside the tubular front
extension of the main frame; and lastly, the swing-joint or Stanley
head.
No very startling difference in the durability of these two heads has
as yet developed itself. The telescope is often hung in balls, which
makes it work as freely as the Stanley, if not more so; it has also a
little advantage in appearance; still, a large majority of the makers
have adopted the Stanley, probably because it is a little cheaper and
quite as efficient. There seems to be less disadvantage in the slant
of the front fork than might have been expected. According to an old
theory in the Ordinary, the more nearly vertical the head, the less
“sensitive” the steering; but experience demonstrates that by practice
all machines are so easily steered that the point is really not so
vital.
The original Rover machine as put upon the market has everything
combined to give it a full slant in the neck; that is to say, it has a
large thirty-six-inch front wheel and no curve to the fork, while in
other machines of the same general pattern a thirty-inch front wheel
is used with considerable curve to the fork, which taken together make
the neck almost vertical; riders, however, are equally satisfied with
either style.
It will be well to notice here that though I speak of the curve of the
fork in relation to steering, it really has necessarily nothing to do
with it, since a perfectly straight fork could have a more vertical
head bearing than one much curved.
The slant of the pivotal line is the important feature, and this may
be varied in either by bending the fork or, in the Stanley, by setting
back the lower bearing.
The four drawings below show necks of equal slant and considerable
variation in the curve or shape of the forks.
[Illustration: Rear-driver front forks.
Fig. 1
Fig. 2
Fig. 3
Fig. 4]
Any of the four patterns above work exactly the same in the hands of
the rider.
So much for the manner of obtaining slant of the head or pivotal
connection, as we shall call it; but as to the amount of this slant it
is desirable to obtain much more can be said.
The great system of castering, so knowingly discussed by some
expounders of cycling faith, has in it really something of substantial
importance. It is asserted that if the machine is so constructed that
the line of pivotal connection strikes the ground in front of the point
of contact of the wheel (see Fig. 1), a castering element comes into
play which will cause the machine to retain its forward course, and
enables the rider to go “hands off.” Note that the line _a b_ strikes
at _c_ in front of _d_.
[Illustration: Fig. 1 Supposed caster.]
[Illustration: Fig. 2 Real caster.]
I have observed many rear-drivers, and cannot see that this makes much
difference; the various kinds seem to be equally well ridden, with
respect to easy steering, if only the riders happen to be thorough
experts; of course all sorts of theories in regard to the action of the
steering have been advanced.
I take it that there is only one truly tenable theory of castering;
this when applied will obviate “sensitiveness” completely and under
all circumstances; it is as follows: The pivotal connection must be
such that the line _a b_ strikes in front of the point of support, as
before spoken of, and it must also be so constructed and placed in such
a position that no motion of the handle-bar will cause the machine
to lower its centre of gravity. If by turning the handles any weight
is lowered, you can depend upon it that the force of gravity, always
tending to lower this weight, will inversely cause the handle-bar to
turn. It will be noticed that when the machine stands upright the
steering apparatus is not in a state of stable equilibrium; that is to
say, the weight of the machine tends to shift the wheel, and it can
hardly keep straight by means of such castering element as results
simply from the line of the pivotal connection striking in front of the
point of contact.
The necessary conditions are as follows (see Fig. 2): The pivotal line
_a b_ must strike at _c_ in front of _d_, and the line _a b c_ must be
vertical in order that no motion on its axis can lower any weight when
the machine stands upright. Now, it follows from these conditions that
the head must be vertical and no part of the pivotal line in the rear
of a vertical through the centre of the wheel.[6]
The automatic steering devices do not work as successfully on a
bicycle as on the leading wheel of a tricycle. There are two principal
plans which have been in use; in one of which a spring forces the
steering-bar into a position for running straight ahead; the other
plan for the same purpose consists in a V slot and pin. In the latter
the weight of the rider keeps the wheel straight by forcing the pin
into the bottom of the V slot, and it will rest there until forced
out by the action of the handle-bar. Either of the above devices
is objectionable in a bicycle, because the constant working of the
steering-bar for the purpose of balancing is so continuous, as compared
with that of steering pure and simple, that any force tending to hold
it in any one position will soon tire the arms and make riding more
laborious.
A new form of the rear-driving Safety was shown in the season of 1887,
invented by a German. I give herewith a cut of the same, citing what he
claims.
[Illustration: The “Rothigiesser” principle.]
“Can be ridden any distance and on any road without using the
handle-bar. The new principle—pedals on the rear wheel and saddle
on the front wheel—is just the reverse of the construction of the
ordinary bicycle, and is the only true principle for a Safety; the
fault of the common rear-driving Safeties being that both saddle
and pedals are fixed on the rear wheel, so that the front wheel
must be controlled by the arms of the rider.”
I have tried the principle, but could not get much out of it. If there
is anything in it at all it would be quite valuable; but I am inclined
to the opinion that the inventor relied rather too much on his theory
and not enough on actual practice. Notice that the handle-bar, trunk of
the body, arms, and saddle are all within one system, there being no
power to steer except in the action between the trunk and feet, instead
of between the arms and trunk, as in other machines.
A new machine has been favorably noticed of late which strikes me as a
modification of the German’s principle, or rather as a combination of
that with the old plan of steering. In this device there is some motion
between the saddle and the handles, as of old, and in addition thereto
we find a motion between the saddle and the pedals, which is intended
possibly to combine all of the good elements. The cut explains itself.
[Illustration: The “Rothigiesser” modification.]
But to return to our mutton. The important features which
have compelled us to recognize with favor this most homely and
awkward-looking machine—the modern rear-driving Safety—are, first, the
safety element, and, secondly, the advantage of being more nearly over
the work, these two features including many minor characteristics. Then
there are a number of independent peculiarities which can hardly be
said to necessarily belong to this type of machine, but which are still
adopted in it, such, for instance, as gearing up and down, foot-rests
for coasting, etc. Until recently there did not seem to be any great
fault in the machine except its looks, but a controversy has arisen
which is not only extremely important but is so far unsettled; I refer
to the discussion of the _side-slip_, which, in showing the number of
explanations that different observers will give for the same set of
facts, has been not unmixed with an element of the humorous.
[6] Since the subject of a patent.