Evening star. [volume] (Washington, D.C.) 1854-1972, 1913-10-26
PNEUMATIC TIRES
NEED PROPER CARE
Sufficient Initiation Is the Key
note of Its Success and
Durability.
AIR CUSHION, NOT FABRIC,
SUSTAINS WEIGHT OF CAR
Some Of the Many Abuses Pointed
Out by Experts-How to
Prevent Waste.

pneumatic tire consists i. of two
things. of which one is as important as
the other One of these is an air
cushion: the other is an envelope for
retaining air under pressure and MAX
ing this air cushion possible. This
envelope is spoken of by the trade as
the tire. and. as every motorist knows,
consists of a casing and an inner tube,
the casing to resist road wear and the
tube to furnish an alright Enclosure
for the air inside. The casing is made
of. rubber and fabric and the tube of
rubber. This mass Of rubber and fabric
construction will not sustain the
weight of any car; it's the air cushion
it retains that supports the cars
weight
Naturally a larger car will require
more of an air cushion than smaller.
and in the same way Il larger tire to-
carry this larger air cushion. A car of
given weight requires a tire of a
given size containing air under a
given pressure.
Let us consider the result when the
tire does not contain proper air pres
sure. 1t has already been pointed out
that the tire itself can't sustain weight,
but that this is the purpose of the air
cushion inside But when this air
cushion consists of air under insult
f1ent pressure the tire is forced to
sustain part of the weight itself. ex-
actly in proportion to the deficiency in
the air pressure. something 1t is not
built to do.
Flattens Tire Out.
The first result is that the weight
above. being no longer properly sus-
tanned. fiattens the tire out where
IL rests on the ground. Then when the
car is put in motion every part of the
tire on reaching the bottom must as
sumo this unnatural fiattened shape.
Each side must bend out and then back
again at every revolution.
The body OF the casing consists of
several plies of fabric united as
whole by the rubber which has been
vulcaniZed through and through And
when the side walls bend in and out
because of under-inaated condition
these fabric layers do not unite their
strength and act as a unit as they are
makes one layer pull against the one
next TO it, They fail TO reinforce one
another as they should
Continually pulling against each other,
these fabric layers in time pull apart,
separating one from the other. The same
conditions which caused them 10 pun
against each other now cause them 10
rub and chafe. This produces friction
and heat. The different layers soon
wear each other out, and SO soon as
some one place becomes too weak TO
sustain the inside air pressure, the tire
gives way with blow
Make Perfect Castings.
The tire manufacturer tries to make
perfect castings and tubes. A perfect
casing and tube is one of the factors
of good tire service. The other factor
is correct air pressure and this is up
to the motorist.
There are several kinds of tire abuse
but proper imitation is so vitality i'm
portant. insufficient imitation is more
damaging than anything else. The sta
tistics compiled by all the leading tire
manufacturers indicate that more than
% per cent of tires that have gone out
OF service prematurely did so because
of insufficient imitation.
There are several indications of under
imitation. The most common one is the
condition of the inside fabric Under
imitation separates the fabric layers, and
this separation shows itself by means OF
ridge or roll of fabric on the lower
part of the side wall on the inside of the
casing. This is before the tire is ready
to give way completely. After tire
with separated fabric is run a while and
then removed IL will be found that the
fabric at the place 1t was rolled up into
a ridge before Is now cracking and be
ginning to break. In this condition il il
soon ready 10 give way.
Loosens the Tread.
Another condition is the loosening al
the tread. determination produces a lit