GSP 9700 Vibration Control System
At Sullivan Tire we believe in using state-of-the-art equipment and trained operators to service your vehicle. The Hunter GSP 9700 in one such machine that our shops are equipped with.
The GSP 9700 extends far beyond the traditional functions of a wheel balancer and "road tests" the wheel before it's on the vehicle to eliminate vibration problems. Hunter's exclusive Road Force Measurement™ System utilizes a "road roller" to measure uniformity of the wheel and tire, simulating a road force test and verifying if the assembly is "round when rolling."
The GSP 9700 will automatically diagnose any vibration problems. With this machine, we can locate and eliminate virtually every cause of vibration relating to the tire and rim and offer our customers 100% quality control.
What is Road Force Measurement?
couresy of Hunter Engineering
Road Force MeasurementRoad Force Measurement? is new to the automotive service industry. This new measurement identifies tire and wheel uniformity, which has been measured for years in assembly plants and manufacturing facilities. Road Force can be used to solve uniformity related tire and wheel vibrations. Tire/wheel assembly uniformity can only be measured under load.
The load roller on the GSP9700 performs a computer simulated "road test". It measures the tire/wheel assembly to determine how "round" the assembly is when rolling under a load. If a tire were not exposed to the road surface, then balance would be more than sufficient. However, not all tires roll round under a load. For example, an egg-shaped tire/wheel assembly can be balanced about its axis, but an egg-shaped tire-wheel loaded against a surface would not give a smooth ride.
To understand the effects of radial force variation on vibration, a model of a tire can be used. The sidewall and footprint can be understood as a collection of springs between the rim and the tire contact patch. If the "springs" are not of uniform stiffness, a varied force is exerted on the axle and causes it to move up and down as the tire rotates and flexes. This movement creates a vibration in the vehicle unrelated to balance.
The GSP9700 load roller applies a force of up to 1400 pounds against the rotating tire/wheel assembly as it performs the Road Force Measurement?. The GSP9700 measures loaded radial runout of the tire/wheel assembly within 0.002". It plots data points as the component is rotated and calculates the radial first harmonic of the tire/wheel assembly and the first harmonic of wheel runout. The peak-to-peak value (Total Indicated Runout) and second, third and fourth harmonics of Road Force are also calculated and used for diagnostics. These measurements are all displayed on other screens.
The measurements of loaded radial runout are converted to Road Force Measurement in pounds, kilograms or Newtons using the following equation:
(Loaded Radial Runout) x (Tire Spring Rate) = Road Force Measurement