New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1917-08-26
Tire Expansion
InHot Weather
Again a Topic
Automobile School Man
Offers Proof for
His Side

A small controversy appears to nave
been stirred up regarding proper infia-
ton of tires in hot weather. Ilr:
makers appear emphatic that the rec
commended imitation should be given, re-
gardess Of the heat of the day. II.
c. Brokaw, an automobile school man.
is insistent that hot weather makes a
difference that should be taken into &C
count. Here is his say:
Should the pressure of tires be de-
creased in hot weather? Is II true. as
! some tire manufacturers claim. that
tires heat more on lower imitation than
when run at the full pressure given
by them? Are tires injured by slight
decrease in the pressure to take into
account the increase due TO friction
and hot pavemcnts?
There have been some criticisms
since MY relation of an experience with
tires while on a tour, in which 1T was
stated that there was twelve-pound
increase in pressure after going forty
miles, so | have been checking up and
testing conditions in city driving.
Recently, 10 determine what effect
the hot weather has on tires in the
city. drove a 3,2OO-pound Model l.
Locomoble, equipped all around with
81 by Al inch tires. through the park
and on Riverside Drive for fifteen miles
at ordinary city traffic speed. which
always is under twenty miles an hour.
The thermometer registered Sc degrees
and the day was partly overcast. so
that the full effect of the sun on the
pavements was not obtained. The t'res
were inflated TO full rinety pounds,
It n n 70
many manufacturers.
AT the end of the run one tire regis
tered 10l pounds, two were 10G and one
vas 90 pounds. The conditions were
not excessive in any way. and the
weather was not abnormal. the road
was smooth. except for very short
stretches. the speed was low and the
tires were of ample size for the weight
of car and load.
"After this test gauge was maze 70
test the fattening effect on the tires
I from a lowered pressure. with the car
/ loaded il was necessary 70 decrease the
pressure in the tires to 60 pounds 70
| have l-l6 inch bulge of the side OF
the tire. At 20 pounds pressure there
was no perceptible fattening.
II believe that more tires are dam
aged by underinhation than by overin-
/ fation, also that new tires will stand
more than 20 per cent overinfatlon
without damage to them. But 1t Is
reasonable to believe that if tire
/ has become weakened from any cause
| il will blow out quicker under IN
! creased pressure. II is also fact that
a tire inflated 10 the pressure recon-
: mended by many manufacturers has
very little resiliency, and the riding
| qualities OF the car are very greatly
! impaired. and when the pressure rises
! slightly higher the tire loses its chief
/ function, that Of absorbing small road
| shocks. Any one who has had the ex-
perience of riding on hard tires knows
/ the discomfort of IL; one might about
as we'll ride on solid tires.
"But all of this comes back to the
question: What is underinfation? A
tire with ten pounds less pressure than
recommended possibly will heat more
than when carrying a full pressure;
but it will very quickly come up to
I the required pressure when in use.
| "As the pressure recommended by
many manufacturers is the extreme so
/ far a. comfort in riding is concerned,
| the car owner must take his choice be-
! tween comfort and tire mileage, assum-
/ inC that slightly less pressure does
| decrease the life Of the tire. | presume
/ the average owner would rather have
! comfortable riding. even at the eX-
I pense of tire mileage, and I am not pre-
/ pared TO admit that decreased mileage
! would be an inevitable result with ten
pounds less pressure. | do not think
! the average man would use a substitute
| for gasolene which gave him all sorts
/ of discomfort because il did not run
I the engine smoothly. even if Il gave
: slightly greater mileage to the gallon.
I Zone manufacturer of fabric tires
/ recommends fifty-six pounds pressure
/ for a 4-inch tire and guarantees 5000
miles. and makes the claim that this
| pressure makes riding much more com
| Portable. Another well known manu-
! facturer advises initiating the tire only
4 to the point where there is no bulge or
/ fattening. and another type of pneu-
matte tire has become very popular be-
cause il requires still less pressure and
makes riding much more comfortable.
where tires are hard and roads are
rough. the machine jumps around so
that it is more likely 70 jump off the
road, so that there is an element of
safety as we'll as comfor- involved.
or hi around comfort, consistent WIN
good tire mileage. have concluded
that a 10-pound decrease in pressure
in hot summer weather is desirable.
The tire cannot be damaged because
after a very few minutes on really hot
pavements the pressure will equal that
recommended BY the most exacting
manufacturer and any overheating due
to this cause would be a matter OF very
short duration.
"As said in a previous article. the
wise owner will test out his car and
tires and find out just the proper
amount Of decrease the tires will stand.
IA a matter of fact. ] have done con-
siderable riding with tire salesman.
ono OF the fellows who is quite in
sistent upon certain pressure. and
it was his invariable practice to de-
fate his tires ten pounds in hot wealth.
or. notwithstanding the fact that. he
/ was after tire mileage.
al OF which poes 10 show that some
people do not always take the advice
,h.s they rive -