COATS ProRide Wheel Balancer - Manual (Page 26)

22 • Important: Always read and follow instructions.
Match Balance (Optimization)
WARNING
Match Balance involves the loosening of
tire beads and the inflation of a tire. Training
is necessary in tire changer operation and
understanding the dangers involved dur-
ing bead seating and tire inflation before
attempting this stage of the Match Balance
procedure. Read the operators manual sup-
plied with the tire changer and consult a
supervisor.
Match Balance (Optimization)
The symbol is displayed automatically for static
out of balance exceeding 30 grams (1.1 oz.)
Use the Match Balance (Tire/Rim Weight Optimiza-
tion) program to determine the best mating of tire and
rim that will result in the least amount of total out of
balance of the assembly. It requires two spins and two
rotations of the tire on the rim. Match Balance may be
needed when:
• The customer complains of ride problems.
• The balancer calculates a high out of balance.
• The balancer calls for Total Static weights in excess
of 3 ounces (85 grams) on passenger car tires.
Having performed a balancing spin:
Press + and follow the on-screen
instructions.
Figure 23 - Optimization
Important: A high out of balance may indicate the
improper mounting of the assembly on the balancer, or
a rim that is out of round or misformed, or a tire with a
bubble or other problem. If the out of balance is exces-
sive, it may be prudent to replace the rim, the tire, or
both. If either is replaced, do not continue with Match
Balance. Balance the new tire and rim and evaluate the
readings.
If you choose to use Match Balance to correct for a
condition, such as a large static out of balance, then
follow the on-screen instructions for the MATCH BAL-
ANCE procedure as outlined in the following steps.
Note: Use this procedure only after the wheel has
spun and the corrective weight amount is displayed.
Note: Presetting of tolerance on the machine. There is
no general rule concerning acceptability of a Max True
Runout Limit (see Balancing Set-up) value. As a first
approximation we consider it correct to use a threshold
of 1 to 1.5 mm.
The much enlarged figures show the outer tire surface
and axis of wheel rotation.
Figure 24 - Runout Measurements
Fig. A - shows measurement of the total Peak-to-Peak
runout defined as maximum radial deviation of the tire
surface.
Fig. B - shows measurement of the runout of the
1st harmonic, i.e. the eccentricity of that circle which
“recopies” the tire shape, by averaging the local devia-
tions of the tire from the round shape.
Obviously the P.P. measurement is normally greater
than that of the 1st harmonic. Tire manufacturers nor-
mally supply two different tolerances for the two eccen-
tricities. The radial and lateral runout measurements
are automatically carried out after the out of balance
measurement without having to go into particular pro-
cedures. Remember to position the sonar sensors in
front of the surface to be measured before pressing the
button.
The maximum limit of the first harmonic can be
set (MAX. TRUE RUNOUT LIMIT). When this limit is
exceeded, the wheel balancer displays a warning and
diagnostic frame indicating an eccentricity condition
that needs to be corrected.
A B