Cycling art, energy, and locomotion : $b A series of remarks on the development of bicycles, tricycles, and man-motor carriagesScott, Robert P. (Robert Pittis)
History
Cycling art, energy, and locomotion : $b A series of remarks on the development of bicycles, tricycles, and man-motor carriages
Scott, Robert P. (Robert Pittis)
Bicycles; Cycling; Tricycles
This familiar phrase means simply that the number of revolutions made
by the drive-wheel in proportion to the number made by the cranks is
greater or less. Broadly, it varies the relative amount of motion of
the pedals, and consequently of the feet of the rider in travelling
over a given distance. In the simple crank device no change can be
made in this respect except in the length of the cranks, but in all of
the sprocket-chain devices it is also possible to change the amount of
motion in the pedals by altering the size of one or the other of the
sprocket-wheels. In lever machines and in those which have the sun and
planet connection, either with an oscillating lever or full revolving
crank, it is generally possible, by some alteration, to produce the
same effect as that of changing a sprocket-wheel as mentioned. The
variation in the length of crank produces an effect comparable to the
change of gearing in so far as the distance through which the feet
travel in covering a certain distance is concerned, but the difference
lies in this, that altering the crank means a given number of
revolutions in a circle of varying radius, while altering the gearing
means a variable number of revolutions in a circle of given radius, in
order to cover a given length of road.
In popular language, if a rider wishes more power, he must lengthen
the crank or decrease the size of the sprocket-wheel on the crank-axle;
_vice versa_, if he desires greater speed and less power, he must
shorten the crank or enlarge the sprocket-wheel connected therewith.
It is needless to say that enlarging the gear-wheel on the crank-axle
produces the same effect as decreasing the size of that on the
drive-wheel.
In a sprocket-crank machine the real question of gearing is whether
to change the length of crank or proportion of the sizes of the
gear-wheels; but you can’t by any combination get power and speed both
with the same amount of work done by the rider.
Simple as all this matter of gearing is, it is probable that there is
no feature in cycles so indefinitely understood, or, we might say, so
persistently distorted. The only trouble is that riders will not stop
to apply a most fundamental law of nature. If we gain speed, we lose
power; if we gain power, we must lose speed. To apply this particularly
to cycles, if you gear up for speed, you must push harder; if we gear
down, we need not push so hard, but must kick faster or go more slowly,
provided in each case the length of crank is the same. We cannot go
fast and push easy unless we increase the strength of the man. To
go over the same distance of given road, the same amount of work is
required, no matter how the machine is arranged through which it is
done.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account