Great Falls tribune. [volume] (Great Falls, Mont.) 1921-current, 1922-07-23
Barney d16ead says:
TIRE MILEAGE

There are many readers Of this
paper who can remember the time
when tires gave 400 miles of service
were considered fairly satisfactory. We
had to pay for those tires as much AS
we now pay for some that give US an
average of 10000 miles. The cost per
mile of tires has dropped consider
ably in the last eight years all because
Of the introduction of the cord tire
and the perfection Of processes for
making them. In the early days of
the cord, the price was prohibitive, so
car owners and factories stuck to fab
RIGS, but when every tire manufactur-
err started to make cords the prices
dropped so that now cord tires are
factory equipment on the majority OF
cars. In a few years the manufac-
ture of fabric tires will stop alto
gether lust as we have discontinued
making plain tread tires. While we
have jumped our conception OF tire life
from 1000 to 10000 we must learn to
care for tires so they will give the
maximum life and that maximum may
be 10000 miles depending on the car
on which the tires are used and the
conditions Of operation.
The part of an automobile tire that
does the real work is the carcass or
inside structure that is made of the
cord fabric. The outer part or tread
that you see simply takes the wear.
You could remove the tread n still
A.. AL1A ,~,1I h. ~o1I Fnn
many miles of service. SO long as
OF course the tread must be tough and
still resilient so that il will last a
long time, and not cut easily.
Black Treads Best
In this connection ! must mention
that black treads as a rule are bet
ter than white or red treads. The
colors are obtained by introducing into
the tread stock a pigment of some sort.
but in the case of good black treads
the pigment not only colors the rub
Der black but mades it tougher. The
black is a carbon black which is moth
ing more than a fine powder. but
that fine powder must not have any
larger particles in it. There are good
black compounds and cheap black ones
Dul IL Is lHipoSSlUlt ~ itll SIAIlply Any
looking at the tread if it is a good or
a poor black. Nearly any black tread
is better than a white one which is
made so by the use of zinc oxide.
Sometimes this oxide and a black are
used together and a gray tread is
formed. Sometimes only a little oxide
is used and this is supposed to pro-
duce a better tread stock than black
used alone.
The idea that red or green or blue
rubber is better than black is all
wrong. These colors are easily OBJ
tainable but they are mere colorings
and haven't the same effect as the
black. The carbon black distributes
itself through the rubber in the pro-
cess of compromising and acts as a
so-called colloid. The physical action
of the black makes the rubber harder
to cut, and it %toughens it s o that it
~resists wear to a greater extent than
white rubber or rubber of any other
color. All sorts Of blacks are obtain
able under such names as micronex
which happens to be one OF the best
eardes of black made.
Getting Maximum Life
But apart from the kind of a tire
you use there is much more to the sub
.ject Of obtaining maximum life. Agreed
that you use a good grade of cord tire
you must first Of all watch initiation.
Especially now that warm weather pre-
walls the tires should cary specified air
presures. Even in a cord tire that can
stand under initiation much better than
fabrics, it is necessary to protect the
carcass from excessive heat due to flex-
ing. Keep your pressure to that speci-
f;aI Gov Tho cirn ron, p ,Ininn yAh,1o
20 pounds per inch of cross-section is
the rule you can drop this to IS or
even 10 II you use oversize tires,
hence easier riding. If you do not use
oversize tires you should carry stan
dard pressures both front and rear. The
following table gives the standard sizes