Tire Pressures & Wheel
Alignment (Cont.)
If the center temperature is higher than the inside
and outside temperatures, the tire is probably over
inflated. Try reducing pressure in 2-psi (14 kPa)
increments and recheck. If the middle temperature
is lower than the inside and outside temperatures,
the tire is probably under inflated. Try increas-
ing pressure in 2-psi (14 kPa) increments and
recheck.
Wheel Alignment
Temperatures can be used to determine condition
of alignment before tread wear is evident. Before
attempting to trouble shoot wheel alignment using
tire temperature readings, ensure tires are properly
inflated to manufacturer's specifications. On many
vehicles, front and rear suspension alignment can
be adjusted. See appropriate service information
to verify if vehicle is equipped with front and rear
alignment adjustments.
Fig. 9: Identifying Toe
The following are alignment conditions that can be
diagnosed using tire temperatures.
n Toe-In - This is when the distance between the
front (1) centerline of the tires is shorter than
the distance between the rear (2) centerline of
the tires. See Fig. 9.
n Toe-Out - This is when the distance between
the rear (2) centerline of the tires is shorter
than the distance between the front (1) center-
line of the tires. See Fig. 9.
n Negative Camber - This is when the top of the
tire leans in toward the vehicle (1). See Fig. 10.
n Positive Camber - This is when the top of the
tire leans away from the vehicle (2). See Fig. 10.
n Caster – Caster will not cause tire tread wear
or increase tire temperatures. Caster can cause
a pull.
To obtain an accurate temperature reading, test
drive vehicle in a low-traffic area, preferably on a
straight, level section of roadway. Operate vehicle
at a safe speed and bring to a complete stop. Try
to avoid any sharp turns or movements during test
drive. Stop vehicle, place in Park (auto trans) or
neutral (manual trans) and set parking brake.
Using the IR thermometer, measure temperature
at inside, center and outside of tire tread surface
on all tires. See Fig. 8.
Fig. 10: Identifying Camber
(Positive Camber Shown)
If tire temperatures are higher on the inside of
both tires, check for the following:
n Excessive toe-out condition.
n Excessive negative camber at both wheels.
n Ride height too low
(causing excessive negative camber).
n Excessive play in steering or suspension
components (tie-rod ends, ball joints,
bushings, etc.).