Omaha daily bee., 1916-06-04
TAB ON SPEED And DISTANCE
Proper Adjustment of 0dometer
Essential to Following
Route Matter.
SIZE OF TIRES THE SECRET

The regular equipment on all cars
commonly known as the "speedometer
equipment" includes mechanism for
indicating both speed and distance.
The odometer part Of the instrument
is the only part which is Of any use
in following route guides.
In following route matter one has
to deal only with what is commonly
called the trip mileage. The total or
gross mileage is seldom used in fol-
lowing route matter, but is necessary
to give a permanent record OF the
total miles travelled by the car. This
trip mileage for the greatest conven-
fence of the tourist who wishes 10
keep accurate check in following data
over strange roads should embody
such features for convenience and ae-
curacy as follows:
/. Legibility-That is, figures
should be large and so placed that
they may be read easily from either
the drivers seat or the seat beside
him.
2. The reset device should be made
that this trip mileage can be turned
to correspond with any mileage in the
route matter at any time at the will
Of the motorist, or 10 zero with the
fcwest possible turns Of the reset de-
vice. This is advisable in order that
the motorist can set his instrument
to check up with any piece OF route
matter at an intermediate point-that
is, a point other than zero
When ii comes 10 inaceuracy OF
readings the fault 900 per cent Of the
time lies with the csspowser, and with
a small amount OF care and foresight
greater accuracy and convenience can
be easily obtained.
In the design and manufacture OF
the instrument the engineer must
naturally work in certain given con-
ditions which are more or less ideal.
lie must take for his standard, the
circumference Of given tire--say
"a by tire.
Tire Size Important.
In figuring the number Of times
that this tire must turn over TO indi-
cate mile he naturally considers a
more or less level, even road surface,
such as is encountered on our boule-
wards or other highly improved roads.
In other words, the design Of all
parts Of the equipment is figured out
in standard conditions. whereas in the
working conditions OF most instru-
ments they come far from complying
with any Of them.
Although there are many features
which will affect the accuracy Of the
reading, the three most important are
enumerated below, which can be af-
fected by the care and attention OF
the owner.
|. Oversize tires are placed on
car without changing the gearing Of
the speedometer equipment.
z. Various non-skid types of tires
are used without recognizing that the
increased circumference caused by the
thicker tread gives decreased mile
age, as the wheel makes fewer revolu-
tions 10 mile.
$. Little or no attention is taken to
keep the tire initiation uniform and up
to the recommended pressure OF the
tire manufacturer, which is necessary
70 give the tire its full circumference.
II the tire is down low il will turn
over more times a mile than il was in
tended TO for its given size.
Most manufacturers to date have ar
ranged various gear ratios, so that il
is necessary to change only one gear
and II is the work OF only a few mo.
ments TO change this to gear having
a less number of teeth, which would
be necessary in this particular in
stance.
Wh-re nonskid tires are used, on
any OF the wheels from which the
speedometer readings are taken il is
almost impossible SO 10 correct the
speedometer equipment that the read
ings will stay uniform and accurate
When such tires are new, the cir
Where tires of such a type are used
on the wheels from which speedome-
ter readings are taken it is simply a
case of having inaccurate readings
part OF the time. Another thing. YOU
might have one old nonskid tire on
and then change to a brand new one
and the readings will change instantly
Of course, 50 that II would be impos.
sible in such conditions 10 have any
equipment that would be accurate.
In the matter OF the initiation. il not
only means increased accuracy to keep