CEMB USA C65 (G) - Manual (Page 19)

I 0559 - 19 GB
5.6 - Eccentricity measurement (optional)
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 eccentricities.
GRAPH 1 : represents the actual Peak-to-Peak eccentricity.
GRAPH 2 : represents the eccentricity of the 1st harmonic. For a wheel in optimum conditions, such graph
should approach a straight line.
When the wheel is moved, the cursor on the screen indicates the actual value, with the phase referred to the
eccentricity measurement sensor.
GRAPH 1 - (yellow)
GRAPH 2 - (red)
At the end of the balancing spin it is possible to automatically measure the eccentricity of the tyre through the
SONAR sensor installed on the guard. The sensor should be positioned by hand in front of the tyre tread.
V.p/p.:
V. 1h.:
V.actual: