The sun. [volume] (New York [N.Y.]) 1833-1916, 1894-12-16
WHY PNEUMATIC TIRES GO FAST.
Interesting Experiments with Rubber-Tired
and Ordinary SteeI-Tircd wheels.

and Ordinary Steei-Tircd Wheels.
from The Hab.
The pneumatic tire is not a new thing. 1t was
made over forty-flvc years before there was such
a thing known as n bicycle. 1t was applied to q
carriage by q man named Thompson OF New
England. 1t was not until forty-fve years later
that the pneumatic tire was applied to bicycles.
In 1915, when Mr.. Thompson thought TO mako
q pneumatic tire for a carriage, II was consid-
cred ar absurdity too great to be mentioned.
1 will first consider the matter Of draught or
road friction. and give you the result OF some
tests which l have recently conducted. and
which are now made public for tho first time.
Two box buggies were employed, one having tho
usual steel-tired wheels. ~ and 4S inches In
diameter, and weighing 254 pounds; the other
having pneumatic-tired wheels, 10 and "a
inches in diameter. and the vehicle weighed 232
pounds. The cross diameter OF the tires was two
incnes. An amount Of weight equal to the diff
ference was placed In the lighter vehicle, and
care was taken to sec that the front wheels Of
the two vehicles bore exactly the same weight.
The surface upon which this first test was
made was a new, hard pine floor, and the wheels
were drawn l%engthwise OF the boards. The
amount OF power required to move these vehi-
Giles under the following conditions was care
fully noted 10y means OF a registering spring
balance. The vehicles empty. II was found
that the power required to start the pneumatic
tires from a standstill was four pounds. and the
power required to haul them at a slow walk was
three and a half to four pounds.
The power required to start steel tires was
found 10 average but three, pounds. and when
started, the power required 10 draw, them was
but one and a half to two pounds, showing an
average difference OF about nifty per cent. in
favor of the steel tires.
Next, an obstruction 5-l6 OF an inch high was
placed in front of and against the wheels of each
vehicle. To haul them over this obstruction
steel tires, IS pounds; with the rubber tires but
III pounds. Then they were drawn at a slow
walk oyer the 5.IS,inc hoo G1 Isn1 Ct on: a ana a. 1t r WAS
Der tires was 3 pounds, and the steel tires .
: Tie 5-l0-inch obstruction was then placed In
front OF the wheels, and the power required TO
haul over i was l3% pounds Tor tile rubber, and
Over the is-lnch obstruction the power re-
quired TO haul the two carriages was 30 pounds
THE two vehicles we're then taken ont OF doors
and placed on u fairly good gravel road;
vehicle, loaded. 400 pounds, averaged 20 pounds.
S x t 5S e eS1nds E&SWitGGr ne, Es9s s,rel. , IT. Sn ySeh SG,IHt
over the same road, the average was Al pounds.
and the extreme, 20, or three times the re-
10 haul these two carriages empty over a
moderately sandy road, the extreme power re.
ssi T : 5q Io. de- 5 on sray SH Win NJ P Sm aSefa .as 81 sp me-
The sttel-tired vehicle required an extreme Of
40 pounds and an average o. sf .,.., ,,r
quired an extreme OF 81, and an average Of 40;
and the rubber, an extreme or 81, and an aver
After these tests had been made over this par
ticular piece Of road, the rubber-tired vehicle
the hauling OF II six times over the road had so
improved it that instead of the extreme pull OF
20 pounds, and an average 81 10, the extreme
was but 10, with an average of s,
II We had a perfectly true surface Tor a road.
and perfectly true metal wheels, nothing better
could be desired; but the words - perfectly true
mean, In the case OF the roads, an impossibllity.
Even the surface OF the best race track Is made
I'M of small DDsITuctiOus.
We have in Waltham, Mass. a bicycle track
w S,snd a rs MADE Ioas al al cement s. r. ss. or s % bs DeIsect. 10
have thought that on a perfect surface a Pneu-
matte tire would be a disadvantage, 20 sug-
gested 70 a bicycle concern that a machine DO
made with solid tires; that is, a narrow wooden
rim and then a coating OF rubber an eighth OF
me, and when / tried IL | was perfectly thunder
struck to lind the track was howhere near per-
phalt We have on Broad street is mll Of little
obs,ructions when you come to run over II with
IL the meial-shod wheel meets a gravel stone
One-quaTter OF an inch in diameter, and that
stone is resting on a hard foundation. the wheel,
with its entire load, must he lifted bodily One-
8 faEs horse 81 an po owen H'B Bat 70 m RSsS U the n ruS Sba tire ire
meets the stone, the vehicle Is not raised percep-
rrnlbBcr' While moss Of tIh weight Is borne By
thai part OF the rubber which ts still resting on
i : only IhSt S q u p'Gds snt IA, TabStTr in one
compress the body OF air which II contains
There arc four reasons why a pneumAtlo trnt-
ting sulkY is faster than the old style; and every
One applies with more or less force TO an elastic
tire OF any kind for any vehicle:
First-It draws more easily.
S~eeond-OWing 10 the small diameter OF the
wheel the sulky Is much sitter eidewise, and the
soft tire stays on the ground and does not slew
in T~ouluing CurNes.
Third When a horse Is being crowded 70 his
utnlust limit. as all horses are supposed 10 be In
a race. his nerves ate under an Intense strain.
ANA he Is kept near the point where he will no
longer hold 10 line unnatural motion OF trOttinE
hut will adopt the run which comes perfectly
natural 10 all four footed animals, The noise
and jar Of any hhFd-tiTed vehicle when a. speed
has murA to do with Tie action OF aly horse.
Fourth The more securely and eomtortAbly
Rny driver T. seated. the better attention be can
gigr atfr t-1ttrr and a nervous driver tends
20 n 10 hFr-s-