Smooth-rolling tyres and wheels can be the difference between having a vibration-free
driving experience or a shaky one. If the tyre and wheel tolerances are not examined,
corrected, or are allowed to "stack up" rather than "cancel out" each other, the
possibility of a balance or road force induced ride vibration exists.
Tyres are made up of internal beads, body plies and belts that are encased in rubber,
assembled and cured. Alloy wheels are cast, cooled and machined. And even though
they both are built to tight tolerances, there is bound to be some unavoidable weight
imbalances during the manufacturing process.
When you consider that a typical passenger car tyre mounted on an alloy wheel weighs
about 18 kilograms, it's amazing that the total amount of imbalance is typically
no more than 80 to 100 grams, or about one-half of one percent. So, if the tyre
and wheel combination isn't balanced with add-on weights, being off even an ounce
or two can cause vibration at highway speeds. Heavier tyre and wheel combinations,
especially those used on light trucks, require more weights to maintain the same
low percentage of imbalance.
The GSP9700 Vibration Control System used by Audi Penfold Burwood’s service specialists
goes far beyond the traditional capabilities of a wheel balancer. In addition to
rectifying the inevitable wheel and tyre imbalance, the GSP9700 Vibration Control
System also "road tests" the mounted assembly to confirm virtually every aspect
of a tyre and wheel combination that might contribute to a vibration.
The GSP9700 Vibration Control System includes Hunter's exclusive Road Force Measurement
System to help detect potential tyre uniformity causes of vibration that are not
balance-related. This system utilizes a "road roller" which applies up to 635 kg
of force against the wheel and tyre assembly to measure their combined uniformity.
This simulated road force test helps verify if the assembly is "round" when rolling
under load.
The GSP9700 Vibration Control System can also measure lateral and radial rim runout
(out of roundness or side-to-side movement) to identify and separate wheel runout
from tyre runout. The system then calculates the contributions of the wheel and
the tyre to a potential vibration and presents the service specialist with easy-to-follow
instructions on the appropriate corrective actions.
If the wheel and tyre are at the edge of acceptable tolerances, Hunter's patented
Force Matching(TM) feature is used to align the high point of the tyre with the
low spot of the rim. This helps maximise ride quality by minimising the effects
of tyre force variation and rim runout. If a wheel or tyre is found to be out of
tolerance, it is then recommended that it be replaced with another wheel or tyre
that is within tolerance.
Once acceptable uniformity has been confirmed, or corrective actions have been completed,
the technician can continue with precision wheel balance.
Click on link to see video demonstration Hunter GSP 9700 Demonstration
How it works
The vehicle leaves with a 'New Car Ride'.
