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Tire and Wheel Rotational Speed Calculation

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

A size P235/75R15 tire rotates ONE complete revolution per second (RPS), or 1 Hz, at a vehicle speed of 8 km/h (5 mph). This means that at 16 km/h (10 mph), the same tire will make TWO complete revolutions in one second, 2 Hz, and so on.

Tire Rotational Speed at 8 km/h (5 mph)

Tire Size Tread Revs/Sec (Hertz)
at 8 km/h (5 mph)
P215/70R16 AL2 1.03
P235/65R16 AL2 1.03
Tread Code
AL2 All Season Touring
  1. Determine the rotational speed of the tires in revolutions per second (RPS), or Hertz (Hz), at 8 km/h (5 mph), based on the size of the tires. Refer to the Tire Rotational Speed table.

    For example: According to the Tire Rotational Speed table, a P235/65R16 tire makes 1.03 revolutions per second (Hz) at a vehicle speed of 8 km/h (5 mph). This means that for every increment of 8 km/h (5 mph) in vehicle speed, the tire's rotation increases by 1.03 revolutions per second, or Hz.

  2. Determine the number of increments of 8 km/h (5 mph) that are present, based on the vehicle speed in km/h (mph) at which the disturbance occurs.

    For example: Assume that a disturbance occurs at a vehicle speed of 96 km/h (60 mph). A speed of 96 km/h (60 mph) has 12 INCREMENTS of 8 km/h (5 mph):

    96 km/h (60 mph) divided by 8 km/h (5 mph) = 12 increments

  3. Determine the rotational speed of the tires in revolutions per second, or Hz, at the specific vehicle speed in km/h (mph) at which the disturbance occurs.

    For example: To determine the tire rotational speed at 96 km/h (60 mph), multiply the number of increments of 8 km/h (5 mph) by the revolutions per second, or Hz, for one increment:

    12 increments X 1.03 Hz = 12.36 Hz, rounded to 12 Hz

    4. IMPORTANT: If the J 38792-A  is not available, compare the calculated rotational speed to the frequency range associated with the symptoms of the vibration concern. See Special Tools . Refer to Symptoms - Vibration Diagnosis and Correction .
  4. Compare the rotational speed of the tires at the specific vehicle speed at which the disturbance occurs, to the dominant frequency recorded on the J 38792-A  during testing. See Special Tools . If the frequencies match, then a first-order disturbance related to the rotation of the tire/wheel assemblies is present.

    If the frequencies do not match, then the disturbance may be related to a higher order of tire/wheel assembly rotation.

  5. To compute higher order tire/wheel assembly rotation related disturbances, multiply the rotational speed of the tires at the specific vehicle speed at which the disturbance occurs, by the order number:

    12 Hz X 2, for second order = 24 Hz second-order tire/wheel assembly rotation related

    12 Hz X 3, for third order = 36 Hz third-order tire/wheel assembly rotation related

    If any of these computations match the frequency of the disturbance, a disturbance of that particular order, relating to the rotation of the tire/wheel assemblies and/or driveline components, also rotating at the same speed, is present.

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