What is Road Force Measurement™?
GSP9720JLR
Road Force Measurement
™ (a roller turning against the tire under
high loads) will most accurately locate and quantify the conditions in the wheel/tire
that cause non-balancer related vibration and radial tire-pull complaints. The
combined effects of geometric (eccentricity) and constructional (hidden internal)
related issues can only be measured if a load is placed against the tire. It is the most
effective way to quantify the effect of all items in a tire and wheel contributing to non-
uniformity of the assembly. Loaded (force) measurement has been the accepted
industrial standard used by tire and vehicle manufacturers for over 30 years.
FORCE VARIATION
Tire Related Forces Are Revealed Only When Testing Under Load
Road Force Measurement is displayed in pound force (Lbs.), kilogram force (Kg.) or
Newton (N). There are two major components analyzed during Road Force
Measurement that contribute to the total non-uniformity of a tire and wheel assembly:
(1) Loaded Runout Measurement and (2) Tire Stiffness Measurement.
Road Force Measurement uniquely combines loaded runout (eccentricity)
measurement of the tire-wheel with the effects of the tire’s overall stiffness.
Eccentricity when stated in terms of runout alone does not quantify the actual force
because the force is dependent on the stiffness of the tire being measured. Runout
does not necessarily create the same force from tire to tire. For example, two tires
with the same runout will differ in their ability to create vibration when a stiff tire
sidewall is compared to a similar tire with soft sidewall. The stiffness of the tire will
reduce or increase the eccentricity of the assembly when rolling under load.
Runout Measurement
is a distance measurement not a force. Runout is traditionally
measured in thousandths of inches (0.000”) or hundredths of millimeters (0.00mm).
Runout can be measured in an unloaded/free state or loaded “road test” condition.
Runout measurement of a tire is a compromise compared to calculating forces and is
not as effective when diagnosing vibration problems. Runout measurement in a
loaded “road test” condition is faster than unloaded runout measurement, however it
is not as effective as calculating the Road Force since the stiffness effect of the tire
are not taken into consideration.
OUT-OF-ROUND
TIRE
OUT-OF-ROUND
RIM
Runout (Eccentricity) is the Only Part of the Vibration Measurement Needed
GSP9720JLR Wheel Balancer Operation Instructions
Theory of Operation
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Summary of Contents for GSP9700 Series
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