The Washington times., 1915-12-11
Weight and Distribution Are
Chief Among Many Other
Factors.
PRESSURE GAUGE NECESSARY
Storage Deterioration May Be
Avoided by Excluding Light
and Heat.

Tire usace, with suggestions for re-
ducing expense, is the theme OF tnis
series of eight articles hy j. J. lfaas,
manager OF the Washington branch of
the Firestone Tire and Rubber Sora-
psny.
iris il the fourth In the series. Sue
cessive articles will appear in tho auto
mobile section Of The Times each Sat-
urday.
No. 4--Inflation and Storage.
BY J. J. HAAS.
inf ATION-The atyle of car con-
struction. power. speed. road conditions.
the exoert or careless driver and es-
pecially the weight and it's distribution
play an impor tnnt Fart with tho strains
10 which the tires will be subiectetl-
consequently. e fixed rule for imitation
would in view of these things. produce
different results.
Ordinarily. tho tires OH front wheels
should be inflated between fifteen and
eighteen pounds per inch of tire Sec
tion and tho rear tires fifteen to twenty
pounds per inch OF tire section.
Ressn1y ~ fs. e the tire. !, nrGmsry
fly. but Is largely influenced by the In
fation and weight carried. Naturally a
four-inch tire inflated to seventy rounds
air sur d. ard ssIryps s3 pounds
size OF tire with the same imitation and
carry TO pounds weight. The heavier
weight causes more detection Of the
tires on the ground and increases the
to the comfort of the ride. Increasing
tho detection or 1attcning of tires.
either by extra weight or reducing the
ton to be absorbed Gy the tires rather
than by the springs Of The car.
Effect of Flatteuing.
When soft. the tire runs AGAINST a
wave in tho tread rubber which will
from excessive stretching and heatinG.
pull away and separate from carcass or
body. The heat from increased ac-
tion in the side walls Of under inflated
hcsivencss between the fabric layers-de-
vulcaniZation takes place. 20 some cx-
gree. Too much detection OF tire also
means an irregular tension Of one layer
pull apart. chafe. and later. when
striking a stone. rough place or rut. .
blowout may occur.
There seems to be an impression Of
danger from blowouts due to expansion.
especially during the hot weather.
There Is some expansion. but. as q mat
ter Of fact. It is not in proportion to the
increase in temperature. for examDle!
II the temperature Of the air In tire
increases from sixty to eighty degrees,
1t does not follow that the air pressure
per square inch increases from sixty to
eighty pounds. 1t actually means an
increase Of three pounds pressure Der
square inch: that is. the pressure In
New tires stretch slightly after in
service Q while, and inner tubes, when
heated to certain degrea, are slightly
pcrmeable to nitrogen and occasional
teriora ting effects of stale air can be
avoided by filing the tires with q fresh
supply Of air. at least two or three
times a year.
Use Pressure Guage.
The tires should not be inflated with
the exhaust from the engine. as oil and
Ger tain gases are destructive to rubber
this docs not have reference to pumps
operated by power from the engine.
Dent make the mistake of guessing at
the imitation from appearances or by
striking the tires with q hammer: use
a pressure gauge at least every week:
tires sometimes appear to round pretty
well. but. when tested with a gauge it
may be found that the pressure Is en-
We believe the most satisfactory infia-
ton method Is to pump up the tires In
accordance with formula. Then. il
necessary, reduce the pressure slightly
tion to the car and traction slippage of
the rear wheels. Make a record Of the
pounds pressure at this point. and, il
always maintained. the greatest cf-
hcency, from tires and car will be en-
joyed.
Deterioration, contrary to the general
impression, Is not necessarily a result
Of age. but is largely Influenced by the
conditions under which tires are held
in stock
Effect of Light.
When exposed to the light and sun,
especially to the hot summer sun, the
rubber will dry out, harden, and the
efficiency and life OF the tire will be i'm
paired AS q protection from light,