Evening star. [volume] (Washington, D.C.) 1854-1972, 1932-12-18
ADJUST NEW CARS
To TIRE EFFECTS
Engineers Find Remedy for
"Shimmy" and "Wander'
Laid to Balloons.
Special Dispatch to The Star.

| Special Dispatch to The Star.
DETROIT, December 17.--Tire pc
culiarities that engineering skill has had
to cope with in producing the new mo-
tor cars for 1888 have been q topic Of
discussion this week.
At Cleveland the Society Of Automo-
| tive Engineers devoted q session to this
subject and progressive steps that have
| resulted in the production and use OF
new super-balloonS Of the "air-wheeP'
types were analysed. They were sur
veyed as the result of research conduct
ed by tire company and an automobile
factory staff.
DR.. B. j. Lemon of the United States
Rubber Co. talked from the tire-makers
side and Tore Franzen, experimental
engineer Of the Chrysler forces, trans
mitted findings from the chassis ana
spring suspension angle. Facts MI.
Franzen revealed embodied the com
posite findings of road testing conduct
ed over q period Of months, which were
reported by Fred NJ Zeder, vice presi-
dent in charge Of Chrysler engineering
work.
Effects on Car Studied.
The findings made clear differences
In car reactions to tire contact with the
roadway, recurring since the flrst bal
loon types came into use.
Tire wander" for example. gives
car the motion of a fish swimming. It's
chief cause Is under imitation OF tires,
and loW-preSsure tires generally are
prone to it. A remedy for it has been
found by altering the angle OF the KING
pins in the front axle. More reversible
steering gears have helped. together
with Increased freedom OF steering
Joints and bearings.
Then there Is "tramping," which
comes from lack OF balance W.,
at one point by the addition OF the tire
valve and stem has been known to cause
this. Wheel balancing machines nave
been developed to correct 1t.
Tire Skinny" Traced.
Tire "shimmy" Is allied to "tramping
and also may be traced to steering syS-
TENS. In most cars now. the XIX
shackle in the spring suspension eilml-
mates it or q cross-steerlng arrange
ment is reStorted to. ,o--
Mr.. Franzen's paper goes on TO con-
cede that parking with low plesSu:,
tires is more difficult than II Is VIII
conventional tire equipment. 10 mee'
the new conditions set up by the SUP
balloons. increases have been mace IN
the steering gear efficiency In prefer
ence to increasing gear ratios. Ihls Is
to avoid unpleasant high-speed conol-
tions common to high-gear ratios.
Riding quality, it is pointed out, as
vet is highly abstract subject ana
dependent on many functions other
than those Of tires. Up to date. there
is no measuring stick available lor
riding quality and it is necessary 10
be satisfied with opinions.
The consensus, in Mr.. Franzens view,
is that the super-balloons WIN tneiI
lower pressure give increased comloit.
Some of this comfort comes from Tue
elimination of high frequency oscllia-
lions which ordinarily manifest tnem-
selves as body noises and rattles.
Fuel Use Increase Small.
"Step by STEP" he said. lit was found
out how to apply the new tires so tnat
today a tire life very similar to that OF
the standard balloon tire may be an
ticipated" :.
Answering a question whether
takes more gasoline to run car with
low pressure tire than with the con.
ventional kind. Mr.. Franzen cited test
findings showing the differences are in
significant.
Two cars identical in every respect
we're equipped with 17x5.25 (the balloon
size) and lex6 tires, respectively. For
a cross-country run Of 1000 miles, the
fuel consumption of the car with the
17x5.25 tires were 161 miles per gallon.
while that Of the car with the l6xo
tires was 1876 miles per gallon.
Summing up the recommendations
for the use of super-balloons. Mr.. Fran
zen enumerated better traction. better
starts. better stops, less body vibration,
longer body life. better ride and better
appearance in their favor.
(Copyright. 1892 by the North American
Newspaper Alliance, 1nc)