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Tire Balancing

Precision Tire Balancing

Smooth-rolling tires and wheels can be the difference between having a vibration-free driving experience or a shaky one. If the tire 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.

Tires 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 tire mounted on an alloy wheel weighs about 40 pounds, it's amazing that the total amount of imbalance is typically no more than three to four ounces, or about one-half of one percent. So, if the tire and wheel combination isn't balanced with add-on weights, being off even an ounce or two can cause vibration at highway speeds.

Recommended Interval

Infiniti does not have a recommended interval.  Our expedience has shown that  most vehicles will benefit from tire balance one a year.

Tire Balancing at Advanced Level > Road Force Measurement

Road Force Measurement is new to the automotive service industry. This new measurement uses a load roller to perform 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.



Beshoff uses a state of the art Hunter GSP9700 precision balance machine which 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 provided to you in a print out.

All tires have some non-uniformity in the sidewall and/or footprint due to variables in the manufacturing process. Unlike balancing, there is often a small amount of RFV remaining in the tire/wheel assembly after ForceMatching and this is generally acceptable.





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