New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1921-07-31
IN Hot Weather
Your Tires Need To
Be Watched Closely
Motor Car Expert Advises a
Slightly Reduced Pressure
TO Compensate for Road
and Atmospheric Heating
By II. Clifford Brokaw
Technical Director West Side Y. NJ
ilAL,Ia C.LI

Tech3ucQt Director W esq Stde \. M.
C. A. Automobile Schools
There are many hot weather all
vents to which the automobile is sus-
rantible; overheating lhe engine,
wbich | discussed in rec1nt article, is
"nlv one. Certain forms of tire
trouble sometimes come in the good
lid summertime which might not occur
IN cooler weather. If the tires are in
aated to too high a pressure the car
rides as though equipped with solid
r,bber, rather than pneumatic tires. In
addition to the discomfort to passen-
rers. there is excessive raStling of all
narts of the car, the heavy vibration
ioosening nuts and bolts aad tending to
shake the entire car to pieces. When
rounding q curve, if the road is some
what rough. the car has strong tend
ency toward going sidewise, like a
crab. ard there is additional danger of
skidding on smooth, wet pavements,
A lot of this sort of trouble can be
avoided by not keeping the tire pres
sure quite as high in hot weather as in
cold. Considerable heat is generated by
rolling tire over the ground. This
heat expands the.air in the tire and in
treases the pressure. In the winter
time this heat is absorbed to a large
extent by the cold atmosphere and the
cold, wet pavements; therefore the
pressure does not vary so much In
the summer the roads are very hot, the
atmospheric temperature is high and
the heat, generated by friction, is not
carried off to any appreciable extent.
On a recent trip l noticed the car
was riding harder than usual | tested
the tires and found they were above
normal in pressure. After letting out
some of the air the car rode easier.
Difference of Twelve Pounds
To find out just what the difference
in pressure would be | took the pres
sure OF each tire the next morning be-
fore leaving the garage. After rolling
about forty miles at an average speed
of twenty-five miles an hour | took the
pressure again. 1t had increased about
twelve pounds in each tire.
Manufacturers of fabric tires insist
that ther tres be kept inflated in ac-
cordance with their specifications. If
this be done, however, in hot weather
especially, the tires have very little re-
siliency; and discomfort and some
times even danger, due to the tendency
result. This, no doubt, in a large
measure, accounts for the popularity of
the cord tires, in which considerably
less pressure may be maintained with
out damage to the tire.
Of course it is generally known that
more fabric tires are damaged by un-
derinhation than by overinfiation. be-
cause the former breaks down the side
walls Of the tires through running fiat,
while overiniatlon usually causes a
blow out only when the tire is weak al
some point. This fact must be taken
into consideration, and for this reason
care must be exercised in whatever al
lowance is made in tire pressure on ac-
count of the summer heat 1t would be
good practice, however, in hot wealth
or to leave the garage with the tire
pressure about ten pounds less than
that usually specified as being normal
~ correct.
Try 1t Out Out for Yourself
1t would also be a good practice for
the driver to test out his tires after
running at a good clip on a hot day
to find out for himself just how his
particular tires react to the heat A
little of such experimenting will soon
indicate to him just about what allow
ance ne should make for hot weather
in the imitation of his own tires.
The question OF tire imitation may be
question OF sacrificing a little on the
life of tire in order to secure a
greater amount of comfort in riding
Practically every owner of a car would
be unwilling to use a substitute for
gasoline, even though the substitute
were cheaper or even though it gave a
greater number of miles per gallon, if
the result were going to be lack of
smoothness in the running of the en-
CINE. And while it cannot be taken
for granted that little less air in the
Flres makes them wear out much fas-
ter, if at all, even if this result were
sure to obtain the added comfort Sc
cured would doubtless be worth more
to the owner of the car than whatever
little extra cost there might be in
volved.
For all-around comfort it is logical
to conclude that slight decrease in
pressure in hot weather is desirable
Certainly this procedure cannot dam
age the tires to any considerable ex-
tent, because after few miles of driy-
ing in warm weather the pressure will
equal Shat recommended by the most
exacting manufacturer of tires, and any
overheating due to this cause would be
a matter of very short duration.
Use Common Sense
In fact, | have known Of some tire
statesmen who are quite insistent upon
a certain pressure being maintained in
the tires they sell, and yet who make
1t their invariabie practice to debate
their tires about ten pounds in hot
weather. These statesmen certainly
want the greatest possible tire mileage
1t is safe to follow their conception of
combination of mileage, safety and
comfort. This is simply using COM
mon sense methods in regard to tires in
the good old summertime.
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