Evening star., 1924-02-24
BALANCE REQUIRED
|NBALL0ON TIRES
Otherwise They Cause Car to
Shimmy BadIy-Tests
Determine Cause.

Ever since the bafloon TIRE mas dp-
peared there have been rumors Of
unseemly behavior at high speeds.
Not all the time, but just on oc-
casions, cars equipped with the big
tires showed a tendency to excess
sive vibration.
No one knew what caused II. It
was annoying to drivers, but as there
were SO many offsetting advantages.
and, as there did not seem to be any
help for it, it was merely accepted
as one of the inevitable accompani-
ments Of balloon tires.
Engineers called it the balloon
tire shimmy," and let it go at that.
But when balloon tires invaded
Marysville last year. and c. Harold
Wills discovered that under certain
big tires. even Wills Sainte Claire
cars induleed in the undignified
wiggle. he began to take the matter
seriously. and unhesitatingly de-
clared that either the shimmy or the
balloon tire must go.
Series Of Tests.
Then began probably the most in
teresting series OF tire tests that
has ever been undertaken.
One very prominent manufacturer
has declared that the results achieved
are the most important contribution
to tire development that have been
made in many years.
In order to study the matter scien-
tifically, Wills Sainte Claire engineers
selected a five-mile stretch of con-
crete and drove cars equipped with
balaloon tires back and forth over
1t under varying conditions of speed
and load. Accurate tabulations Of re-
suits were made.
1t was discovered that sometimes
driving down the road at fifty miles
an hour. quite an excessive vibration
was set up. while after turning the
speed was maintained without any
sign of vibration. Other times the
vibration would be quite moderate.
These varying tendencies indicated
quite clearly that the trouble was
in the tires themselves and not in
the car.
Tires Ont OF Balance.
Mr.. Wills studied the tabulated re-
cults in the light OF known theories
Of vibration and finally declared that
the secret lay in the fact that the
tires were out of balance.
1t is known fact, OF course, that
all tires are to some extent out Of
balance. The valve stem. the over
tapping flap that projects the inner
tube. the overlapping ends Of the
rulcanized. all tend to throw a little
more weight on one side Of the tire
than on the other
In the high-pressure tires Of
smaller sni diameter these, these factors have
In the large tires. however, operat-
cd under. low pressure. the effect was
very marked. When this idea was
first suggested. the tire makers and
their engineers were frankly skep-
AVN a n Ia
They wanted to be shown.
Experiment Succeeds,
In order to demonstrate the theory,
the front end of the car was lacked
up. the heaviest portion of the two
front tires naturally found its way to
the bottom, and in that position the
car ca. was started on its journey down
the road. No vibration resulted. The
car action was as smooth and pleas
ing aS any one could desire
Then the wheels were again lacked
up, the heavy portion of one tire
was placed at the bottom and Of
the other tire at the top.
Under this condition the vibration
was excessive. The radiator SHIN
med like Broadway fiapper.
Then a third test was made with
a heavy portion of one tire at the
bottom and Of the opposite tire half
way up. The vibration was notice.
able, but not excessive.
These tests were repeated and tabu-
lated until there could be no doubt
whatever as to the accuracy of the
conclusions.
The effect was very similar to that
produced in motor by an unbalanced
crankshaft
The problem was put up to the
tire manufacturers, and they heartily
agreed to cooperate with their en-
Sineering and manufacturing facil-
tiles to correct the difficulty.
Balloon tires of the better class
in the future are to be balanced tires.
The first production of these bal
anced tires equip the Wills Sainte
Claire cars exhibited at the show
there.
In operation these tires insure a
perfection OF equilibrium that will
forever ban the balloon tire shimmy
from Wills Sainte Clare cars.
This revolutionary development is
only one of the important improve
ments that have been made in balloon
tire equipment as a result of the ex-
baustive tests conducted during the
past several months at Marysville.
The balloon tires finally adopted
and approved by c. Harold Wills for
Wills Sainte Claire cars have not only
this feature of perfect balance, hut
will show an extreme toughness and
resistance to wear in excess Of any.
thing that has heretofore been
achieved in pneumatic tire develop.
ment.