CEMB USA C68SE (B) - Manual (Page 21)

I 0201 GB- 21
5.7 - DISPENSER
When the dispenser is enabled (see Section ENABLING OF THE DISPENSER), at the end of a spin,
it is possible to have adhesive counterweights of the exact weight measured by the machine (even if
displayed in steps of 5 grams or 1/4 oz).
For this purpose:
1. Press 5 to have the adhesive weight for the outside.
2. Press 3 to have the adhesive weight regarding the inside.
3. If the SPLIT function has been selected, it is also possible to dispense the adhesive weight for values
regarding the split on the two spokes: the dispenser distributes the adhesive weight according to the
positioned spoke. Distribution is disabled for weights less than 5 grams.
5.8 - WHEN AND WHY MATCHING
The C68 software associated with eccentricity measurement is a powerful tool for determining the need
to perform relative rotation between the rim and tyre in order to reduce the eccentricity of the wheel
down to acceptable limits. The principle adopted is based on the consideration that a rim with acceptable
tolerance, mounted with an acceptable tyre, can statistically generate a total eccentricity which is not
acceptable but can be improved by matching.
Generally speaking, rim measurement is not necessary, accurate or useful because:
· To measure the rim it is necessary to remove the tyre. There can by coarse errors on the outside
(e.g.
aluminium wheels!)
· The two rim sides can be eccentric in a very different way. Therefore to which one to make reference?
What is the effect on the tyre mounted?
· To improve the eccentricity of a wheel, the rim should be eccentric, to compensate the tyre. And
viceversa.
· If after a rotation by 180° of a wheel, the value is still out-of-tolerance, either the tyre or rim are too
eccentric: One of the two must be replaced!
SOLUTION:
Rotate the tyre on the rim by 180° RESULT:
wheel
eccentricity 0.3 - 0.4 mm (in tolerance)
wheel
rim
tyre
rotation axle
Ideal wheel
Example 1
Rim + 0.8 mm
Tyre + 0.6 mm
Wheel + 1.3 mm
Eccentricity of the wheel is exces-
sive, due to an acceptable rim or
type but randomly placed in an
“unfortunate” relative position”.