CEMB USA C88 (B) User Manual

Page 23

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4.8.2 - WHEEL ECCENTRICITY MEASUREMENTS

►

The external radial and lateral eccentricity measurements are automatically made at the end of the unbalance mea-
surement without having to perform particular procedures.

Remember to position the sonar sensors in front of the

surface to be measured before pressing the

button.

The much enlarged fi gures show the outer tyre surface and axis of wheel rotation.

Fig. A - shows measurement of the total Peak-to-Peak eccentricity defi ned as maximum radial deviation of the tyre
surface.

Fig. B - shows measurement of the eccentricity of the 1st
harmonic, i.e. the eccentricity of that circle which “recopies”
the tyre shape, by averaging the local deviations of the
tyre from the round shape.

Obviously the P.P. measurement is normally greater than
that of the 1st harmonic. Tyre manufacturers normally
supply two different tolerances for the two eccentrici-
ties.

The maximum limit of the fi rst harmonic can be set (

FIRST HARMONIC LIMIT

). When this limit is exceeded,

the wheel balancer displays the red symbol above the

button to indicate an eccentricity condition that

needs to be corrected.
To go to the eccentricity measurement management frame, press the button

from the unbalance measuring

frame:

The following buttons are enabled:

to go to rim eccentricity measurement (see the specifi c chapter)

to print the eccentricity values measured (option)

to display the graph of peak/peak values