The Washington times., 1914-01-03
TIRE INITIATION RULE
HARD OF DEWS|NG
Firestone Man Tells Of Many
Conditions Governing Usage
and Wear.

There are so many different factors
having an influence on the usage OF
tires that no rule for imitation can be
adopted which win be exactly suitable
to all conditions said L. Grenwald, of
the Firestone Tire and Rubber Com
pany.
THE style Of car construction, the
weight and its distribution, power, road
conditions, speed, the expert or care
less driver, the effects OF climate and
numerous other things all have impor-
tant connections with the strains to
which the tires will be subjected" con-
tinued Greenwald. Consequently, a
fxed rule for the imitation would, in
view Of these things, produce different
rrsults
THE schedules of imitation recon-
mended by the tire companies provide a
basis from which to work Ordinarily,
the tires on front wheels should be in
fiated from fifteen to eighteen pounds
per inch Of tire section, and the rear
tires from fifteen to twenty pounds per
inch Of tire section. For example: Four
inch tires on front wheels, from sixty
TO seventy-two pounds, and the rear
from sixty to eighty pounds. The varia-
ton in these pressures naturally de-
pends upon the things before men,
toned, principally the weight OF car.
For instance, tires on a car weighing
I 800 puonds Do not require as much air
pressure as the tires on q car weigh
ing $500 pounds. The tires ride hard
when pumped Up to q high pressure
and used on light cars, but with the
same pressure ride comfortably on a
heavy car. Z
TN determining the correct size Of
tire and the proper imitation, it Is inn
portant to know the weight Of the car
and its distribution on the front and
rear wheels Run the front half of
the car on platform scales and make
note OF the weight. Then place only
the rear half Of the car on the scales,
recording this weight also. The weight
carried by each tire will be one-half
of either of the respective amounts.
Use a Gauge Weekly.
''Resiliency is primarily governed by
the construction and quality Of the
tires, but is largely influenced by the
imitation and the weight carried. A
four-inch tire inflated to seventy pounds
pressure and carrying a weight Of 500
pounds will naturally ride easier than
the same size tire with the same infia-
ton carrying a weight OF 700 pounds.
The heavier weight causes some defec-
ton of the tire on the ground and in
creases the action adding to the comfort
OF tne rae as Lne de1eCtlOn OF HaII6n-
ing Of the tire Is increased either by
weight or reducing the air pressure,
most of the vibration Is absorbed by
the tires and not by the springs of the
car. The danger is in going to an ex-
treme. and a great many car owners in
this way sacrifice tire efficiency and
maximum mileage.
'If you flnd the tires ride hard when
inflated to eighty pounds pressure 1t
Is safe 10 reduce the pressure to seven
ty-five pounds or seventy pounds, pro-
viding this does not permit the tires to
bulge or fiatten under the weight of
the car.
Don't make the mistake OF. guessing
At the imitation from appearances; use
tire pressure gauge at least once every
week. The tires sometimes appear to
round up pretty well. but when tested
with the gauge you may find that the
pressure Is entirely too low to secure /
he best results"