The Washington times., 1923-09-01
BALLOON TIRES
ARE REACHING !.
PERFECTION
Chassis Engineers Working on
Changes to Prevent "Gal-
Ioping" With New Type.

Returning from the periodic trip
TO the free-air station. how often
we remark upon the disagreeable
shaking.up we receive as the car
runbles along on tires inflated to
the high pressures recommended IN
the instruction book.
This unsatisfactory demonstration
frequently ends In our ignoring the
tire-maker's advice, partially deflnl''
ing the tires and taking our chance
with the puncture, blowout, ana
cracked side-wall hazards.
New Type Developed.
Easy riding must be had at my
cost, The tire engineers, In recog-
milton Of this common practice, are
developing and perfecting q new
type OF tire that will make riding
on loW.pressure air practical. These
tires are called variously, balloon.
iow.pressure, super.cushion, and
doughnut tires. Engineers speak
OF them az air-cushion tires; another
DESIGNATION Ii a large-section thin
wall low.pressure tires, and, though
somewhat involved, this title Ii
most descriptive one
One Of the pioneer experinentats
with this new tire, James f., Hale,
Of the Firestone engineering staff,
read O very comprehensive paper
on the subject before the re2sHt
summer meeting Of the Society OF
Automotive Engineers. Other prorni.
nent tire. authorities also contribute
their opinions The pertinent points
brought out In the paper and meet.
ing are presented herewith for the
citation of all, motorists who crave.
joltleSs transportation.
II we are to have greater cushion
ing for. comfort and protection
against viberations of the car, The
combination of low air-pressure and
o large area OF contact must be
provided. and by employing such
tire constructions that the tire
durability viii not be impaired ;.
Low Pressure Possible.
The "doughnut" tire Is designed
30 that pressures ranging from
twenty to thirty-five pounds per
square inch can be employed In
SEXUAL practice. The section and
side-wall Of. the tire must be
specially designed and proportioned
to Withstand the greater reflections
and bending Of the carcass due TO
the lowered resistance Of the air.
pressure. Otherwise, the tires are
likely to fail because tread and ply
separation might be excessive; also,
the flex4ng Iocalizes halfway up the
sidewalk and may cause fabric
failures on the inside plies. The
destructive effect of this ticking
will be much more pronounced
In q thick-walled than in a thin
walled tire. But, IL we use low
pressure air, the bursting stressts
on the carcass are low enough so
that only a few plies are necessary.
TO an extraordinary degree. bricks
and read irregularities are absorbed
by the low-preseure tires. The
road irregularities. are Touchdown"
and In most cases. obliterated. The
ups-and-d downs In the road are still
there and the car rolls with them.
but everything il cushioned so that
there are no sharp shocks or Jolts.
The driver does not need to pick
out all the good places in a rough
road and q substantially higher
turally the cushioning effect pre-
vents the car from developing rat
ties and creaks. and. lessons me-
chanical depreciation.
Easy On Car.
For instance when dropping into
a chuck hole, the air-cushion tires,
because OF their greater DETECTION
in falling through the distance.
bring the car to rest more gradual
ly; in fact, the effect is more OF q
rolling action.
Many logical questions regarding
the practicability of low-pressure
tires present themselves for investi~
CATION. Will the gasoline consump-
ton be increased? 1T Is claimed by
Mr.. Hale that, in general, these tires
cause neither more nor less fuel to
be consumed than do the high pres
sure pneumatics: Six taxicabs ran
20, 900 miles and averaged 1875 miles
per gallon. One can detect a slight
difference in turning the wheel. In
ordinary driving this effect cannot he
considered serious.
However, whan the car is in close
quarters, such as being parked at
the curb, it Is more difficult to move
the wheels. Perfection Of steering
gears Ia already going forward 70
offset this handicap. There is an in
creased tendency for the front wheels
of the car to shimmy when low-prcs.
sure tires are used. This Is one of
the problems that must be overcome
before the tires can be considered
ready for the general public. The
chassis engineer must cooperate jr1
It's solution by providing more stable
steering connections and eliminating
axle and steering layout faults that
set up this disagreeable oscillation.
Large Area of Contact.
The large area of contact OF the
air-cushion tire, with the greatly in
creased linear total of non-skid edges
having a squeegee effect, seems 70
reduce materially the tendency to
skid on smooth pavement. Air-cnsh-
ion tires hold much better on rough
pavements than do the high pressure
pneumatics.
Their area IS so large and the
carcas so flexible that II folds and
rolls over the rips and hollows in the
road surface so as to maintain
uniformly large area Of contact at all
times. On snow and ice, the control
of the car on air-rusfion tires is
noticeably better. This lesser ten
dency to skid naturally improves the
braking ability.