GMC chervolet camaro 1999 Service Manual page 55

0-52 Vibration Diagnosis and Correction General Information
Calculating Tire Rotation
TIRE/WHEEL AND PROPSHAFT ROTATION
Vehicle Information
km/h
Complaint Speed: _ _ _ _ _ _ _ _ _ _ _ _ (mph)
Symptom:
Frequency:
Engine Speed:
_ _ _ _ _ _ _ _ _ _ _ _ rpm
Gear:
Tire/Wheel Speed
Vibration
Occurs at:
km/h
t-
8(krn/h)
mph+ 5(mph)
Year: _ _ _ _ _ M o d e l : - - - - -
~N: _ _ _ _ _ _ _ _ _ _ _
~
Engine: _ _ _ _ Trans: _ _ _ _ _
Tire Size: _ _ _ _ Axle Ratio: _ _ _ _
TPC Spec: _ _ _ _ _ _ _ _ _ _ _
D
Increments
of
a km/h
(5mph)
x
tireRPs·
at8km/h
(5mph)
(from chart)
I
TireM'heel Speed,
RPS (Hz)
1st
order
1st
order
1st
order
Propeller
Shaft
Speed
1st order
tire
1st order
propshatt
x2
x3
x
(axle ratio)
x2
'RPS- rewlutlon& per second; equates to cycles per second (Hz).
Determine the rotational speed of the tires in
revolutions per second, or Hertz (Hz), based on the
vehicle speed at which the vibration occurs. In order to
determine the rotational speed, use the following
procedure:
1. Determine the speed at which the vibration
occurs.
2. Determine the number of 8 km/h (5 mph)
increments:
• Divide the complaint speed by eight when
using kilometers.
• Divide the complaint speed by five when
using miles.
I
2nd order
3rd order
Propeller Shaft Speed
1st
order
2nd order
3. Determine the vehicle tire size.
4. Locate on the table below, the Hertz value at
8 km/h (5 mph) for that tire size.
6509
5. Multiply the Hertz value by the number·of 8 km/h
(5 mph) increments.
6. The result is the rotational speed of the tires in
Hertz at the complaint speed. If this figure
matches the vibration frequency, a first-order
vibration is present in the tire and wheel assembly.
I
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