00-03-10-006I

File in Section:
Bulletin No.:
Service Bulletin
Date:
03 - Suspension
00-03-10-006I
February, 2013
INFORMATION
Subject:
Information on Tire Radial Force Variation (RFV)
Models:
2013 and Prior GM Passenger Cars and Light Duty Trucks
This bulletin is being revised to reinforce the importance of performing a wheel
centering check on wheel balancers so equipped. Please discard Corporate Bulletin
Number 00-03-10-006H (Section 03 – Suspension).
Important:
• Before measuring tires on GM approved tire force
variation measurement equipment, the vehicle
MUST be driven a minimum of 24 km (15 mi) to
ensure removal of any flat-spotting. Refer to the
latest version of Corporate Bulletin
Number 03-03-10-007: Tire/Wheel Characteristics
of GM Original Equipment Tires.
• GM approved tire force variation measurement
equipment MUST be calibrated prior to measuring
tire/wheel assemblies for each vehicle.
Note: If the equipment being used is capable of
performing a centering check, the centering check must
be completed before taking measurements of balance
or RFV.
The purpose of this bulletin is to provide guidance to
GM dealers when using GM approved tire force
variation measurement equipment. This type of
equipment can be a valuable tool in diagnosing vehicle
ride concerns. The most common ride concern
involving tire radial force variation is highway speed
(105-115 km/h (65-70 mph) shake on smooth roads.
Tire related smooth road highway speed shake can be
caused by three conditions: imbalance, out of round
and tire force variation. These three conditions are not
necessarily related. All three conditions must be
addressed.
Imbalance is normally addressed first, because it is the
simpler of the three to correct. Off-vehicle, two plane
dynamic wheel balancers are readily available and can
accurately correct imbalance. Balancer calibration and
maintenance, proper attachment of the wheel to the
balancer, and proper balance weights, are all factors
required for a quality balance. However, a perfectly
balanced tire/wheel assembly can still be “oval shaped”
and cause a vibration.
Before balancing, perform the following procedures.
Copyright 2013 General Motors LLC. All Rights Reserved.
Tire and Wheel Diagnosis
1. Set the tire pressure to the placard values.
2. With the vehicle raised, ensure the wheels are
centered on the hub by loosening all wheel nuts
and hand-tightening all nuts first by hand while
shaking the wheel, then torque to specifications
using a torque wrench, NOT a torque stick.
3. Visually inspect the tires and the wheels. Inspect
for evidence of the following conditions and correct
as necessary:
• Missing balance weights
• Bent rim flange
• Irregular tire wear
• Incomplete bead seating
• Tire irregularities (including pressure settings)
• Mud/ice build-up in wheel
• Stones in the tire tread
• Remove any aftermarket wheels and/or tires
and restore vehicle to original condition prior to
diagnosing a smooth road shake condition.
4. Road test the vehicle using the Electronic Vibration
Analyzer (EVA) essential tool. Drive within posted
speed limits at 105-115 km/h (65-70 mph) for a
sufficient distance on a known, smooth road
surface to duplicate the condition. Determine if the
vehicle is sensitive to brake apply. If the brakes are
applied lightly and the pulsation felt in the steering
wheel increases, refer to the Brakes section of the
service manual that deals with brake-induced
pulsation. If you can start to hear the vibration as a
low boom noise (in addition to feeling it), but
cannot see it, the vehicle likely has a first order
(one pulse per propshaft revolution) driveline
vibration. Driveline first order vibrations are high
enough in frequency that most humans can start to
hear them at highway speeds, but are too high to
be able to be easily seen. These issues can be
caused by driveline imbalance or misalignment. If
Page 2
February, 2013
the vehicle exhibits this low boom and the booming
pulses in-and-out on a regular basis (like a
throbbing), chances are good that the vehicle
could have driveline vibration. This type of
vibration is normally felt more in the “seat of the
pants” than the steering wheel.
5. Next, record the Hertz (Hz) reading as displayed
by the EVA onto the tire data worksheet found at
the end of this bulletin. This should be done after a
tire break-in period of at least 24 km (15 mi) at
72 km/h (45 mph) or greater, in order to eliminate
any possible tire flat-spotting. This reading
confirms what the vehicle vibration frequency is
prior to vehicle service and documents the amount
of improvement occurring as the result of the
various steps taken to repair. Completing the
Steering Wheel Shake Worksheet below is
required. A copy of the completed worksheet must
be saved with the R.O. and a copy included with
any parts returned to the Warranty Parts Center for
analysis. A reading of 35 to 50 Hz typically
indicates a first order propshaft vibration. If this is
the situation, refer to the latest version of
Corporate Bulletin Number 08-07-30-044.
Generally, a reading between 10 and 20 Hz
indicates a tire/wheel vibration and if this is the
reading obtained, continue using this bulletin.
If the tire 1st order vibration goes away and stays
away during this evaluation, the cause is likely tire
flat-spotting. Tire flat-spotting vibration may come
and go at any speed over 72 km/h (45 mph) during
the first 10 minutes of operation, if vibration
continues after 10 minutes of driving at speeds
greater than 72 km/h (45 mph), tire flat-spotting can
be ruled out as the cause for vibration.
6. If flat-spotting is the cause, provide the explanation
that this has occurred due to the vehicle being
parked for long periods of time and that the
nature of the tire is to take a set. Refer to the
latest version of Corporate Bulletin
Number 03-03-10-007: Information on Tire/Wheel
Characteristics (Vibration, Balance, Shake, Flat
Spotting) of GM Original Equipment Tires.
7. If the road test indicates a shake/vibration exists,
check the imbalance of each tire/wheel assembly
on a known, calibrated, off-car dynamic balancer.
Make sure the mounting surface of the wheel
and the surface of the balancer are absolutely
clean and free of debris. Be sure to choose the
proper cone/collet for the wheel, and always
use the pilot bore for centering. Never center
the wheel using the hub-cap bore since it is not
a precision machined surface. Perform the
centering check if the equipment is capable of a
centering check. If any assembly calls for more
than ¼ ounce on either rim flange, remove all
balance weights and rebalance to as close to zero
as possible. If you can see the vibration (along with
feeling it) in the steering wheel (driving straight
without your hands on the wheel), it is very likely to
Bulletin No.: 00-03-10-006I
be a tire/wheel first order (one pulse per revolution)
disturbance. First order disturbances can be
caused by imbalance as well as non-uniformities in
tires, wheels or hubs. This first order frequency is
too low for a human to hear, but if the amplitude is
high enough, it can be seen.
If a vibration or shake still exists after balancing, any
out of round conditions, of the wheel, and force
variation conditions of the tire, must be addressed. GM
approved tire force variation measurement equipment
can address both (it is also a wheel balancer).
Tire radial force vibration (RFV) can be defined as the
amount of stiffness variation the tire will produce in one
revolution under a constant load. Radial force variation
is what the vehicle feels because the load (weight) of
the vehicle is always on the tires. Although free runout
of tires (not under load) is not always a good indicator
of a smooth ride, it is critical that total tire/wheel
assembly runout be within specification.
Tire force variation measurement equipment loads the
tire, similar to on the vehicle, and measures radial force
variation of the tire/wheel assembly. Note that the
wheel is affecting the tire's RFV measurement at this
point. To isolate the wheel, its runout must be
measured. This can be easily done on GM approved
tire force variation measurement equipment, without
the need to set up dial indicators. If the wheel meets the
runout specification, the tire's RFV can then be
addressed.
After measuring the tire/wheel assembly under load,
and the wheel alone, the machine then calculates
(predicts) the radial force variation of the tire. However,
because this is a prediction that can include mounting
inaccuracies, and the load wheel is much smaller in
diameter than used in tire production, this type of
service equipment should NOT be used to audit new
tires. Rather, it should be used as a service diagnostic
tool to minimize radial force variation of the tire/wheel
assembly.
GM approved tire force variation measurement
equipment does an excellent job of measuring wheel
runout, and of finding the low point of the wheel (for
runout) and the high point of the tire (for radial force
variation). This allows the tire to be matched mounted
to the wheel for lowest tire/wheel assembly force
variation.
The machine will simplify this process into easy steps.
The following assembly radial force variation numbers
should be used as a guide:
P-Metric tires of
passenger cars
18 lbs (8 kg) or less
P-Metric tires on light trucks
24 lbs (11 kg) or less
LT-tires on light trucks
35 lbs (16 kg) or less
When measuring RFV and match mounting tires
perform the following steps.
Bulletin No.: 00-03-10-006I
February, 2013
Measuring Wheel Runout and Assembly Radial
Force Variation
Important: The completed worksheet at the end of this
bulletin must be attached to the hard copy of the repair
order.
•
•
Measure radial force variation and radial runout.
If a road force/balancing machine is used, record
the radial force variation (RFV) on the worksheet
at the end of this bulletin. It may be of benefit to
have the lowest RFV assembly to the front left
corner . If the machine is not available and the
EVA data suggests there is an issue, swap the tire
and wheel assemblies from the front to the back.
Re-check on the EVA and if the problem still
exists, test another vehicle to find assemblies that
do not exhibit the same frequency. If the subject
vehicle exhibits vibration in the seat, then swap
only the rear assemblies and see if the problem
continues. If the subject vehicle exhibits vibration
in the steering wheel, swap only the front
assemblies and see if the problem continues. If
the subject vehicle continues to vibrate after
swapping two assemblies then swap all four. If the
vibration still exists, continue below.
• If a runout/balancing machine is used, record the
radial runout of the tire/wheel assemblies on the
worksheet at the end of this bulletin. If one or more
of the tire/wheel assemblies are more than
0.040 in (1.02 mm), match mount the tire to the
wheel to get below 0.040 in (1.02 mm). For
sensitive customers, readings of 0.030 inch
(0.76 mm) or less are preferable, it may also be of
benefit to have the lowest runout assembly to the
front left corner. If the machine is not available and
the EVA data suggests there is an issue, swap the
tire and wheel assemblies from the front to the
back. Re-check on the EVA and if the problem still
exists, test another vehicle to find tires that do not
exhibit the same frequency and swap those tires
onto the subject vehicle.
• After match mounting, the tire/wheel assembly
must be rebalanced.
If match mounting tires to in-spec wheels produces
assembly values higher than these, tire replacement
may be necessary. Replacing tires at lower values will
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probably mean good tires are being condemned.
Because tires can sometimes become temporarily
flat-spotted, which will affect force variation, it is
important that the vehicle be driven at least 24 km
(15 mi) prior to measuring. Tire pressure must also be
adjusted to the usage pressure on the vehicle's tire
placard prior to measuring.
Most GM vehicles will tolerate radial force variation up
to these levels. However, some vehicles are more
sensitive, and may require lower levels. Also, there are
other tire parameters that GM approved tire force
variation measurement equipment cannot measure that
may be a factor. In such cases, TAC should be
contacted for further instructions.
Important:
• When mounting a GM wheel to a wheel balancer/
force variation machine, always use the wheel's
center pilot hole. This is the primary centering
mechanism on all GM wheels; the bolt holes are
secondary. Usually a back cone method to the
machine should be used. For added accuracy and
repeatability, a flange plate should be used to
clamp the wheel onto the cone and machine. This
system is offered by all balancer manufacturers in
GM's dealer program.
• Any type of service equipment that removes tread
rubber by grinding, buffing or truing is NOT
recommended, and may void the tire warranty.
However, tires may have been ground by the tire
company as part of their tire manufacturing
process. This is a legitimate procedure.
• If the equipment being used is capable of
performing a centering check, the centering check
must be completed before taking measurements
of balance or RFV.
Steering Wheel Shake Worksheet
When diagnosing vibration concerns, use the following
worksheet in conjunction with the appropriate Vibration
Analysis-Road testing procedure in the Vibration
Correction sub-section in SI.
Refer to the appropriate section of SI for specifications
and repair procedures that are related to the vibration
concern.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.
WE SUPPORT VOLUNTARY
TECHNICIAN
CERTIFICATION
Page 4
February, 2013
Bulletin No.: 00-03-10-006I
Steering Wheel Shake Worksheet
To:
Dealer:
Fax Number:
VIN__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
Procedure Performed By:
Date:
Model:
Year:
Odometer:
VIN __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
TAC Case #, if applicable:
Conditions During Road Test Procedures
As condition occurs: Engine RPM_____________
Vehicle Speed__________________
Vibration/Noise detected during the following road test procedures:
Engine RPM_______________ Vehicle Speed_______________
Slow Acceleration Test: Yes__________ No__________
Neutral Coast-Down Test: Yes__________ No__________
Downshift Test: Yes__________ No__________
Neutral Run-Up Test: Yes__________ No__________
Steering Input Test: Yes__________ No__________
When using the EVA, always take a snapshot. This will help determine which vibration shows up the most.
Important: Vibrate software can also be used to assist in vibration diagnosis. Refer to Vibrate Software Description and
Operation in SI.
EVA Readings
Refer to Electronic Vibration Analyzer (EVA) Description and Operation in SI for more detailed information.
Important: As a reminder, place the EVA sensor where the vibration is mostly felt. Ensure the word “UP” on the sensor is
physically facing up. The typical areas are the seat track, the steering column or the instrument panel. Locating the EVA sensor
on additional area (i.e. the right fender, left fender, right quarter panel, left quarter panel, rear seat track, etc.) may also assist in
determining the component causing the vibration/noise. The key is to look for the same Hz reading with the greatest amplitude
G readings.
Bulletin No.: 00-03-10-006I
February, 2013
Steering Wheel Shake Worksheet
FILL OUT ONLY THE APPLICABLE PORTION OF THE WORKSHEET THAT APPLIES TO THE VIBRATION/NOISE:
Sensor at Steering Column:
1st Line MPH/KPH:__________ HZ:__________ Gs:__________
2nd Line MPH/KPH:__________ HZ:__________ Gs:__________
Sensor at Roof:
1st Line MPH/KPH:__________ HZ:__________ Gs:__________
2nd Line MPH/KPH:__________ HZ:__________ Gs:__________
Sensor at Passenger Seat Rail:
1st Line MPH/KPH:__________ HZ:__________ Gs:__________
2nd Line MPH/KPH:__________ HZ:__________ Gs:__________
Tire Size and Brand:_____________________________________
Wheel/Tire Runouts on vehicle (max. 0.050 in (1.27 mm))
Refer to the latest version of Corporate Bulletin Number 00-03-10-006 for tire radial force variation.
Right rear: Inner lateral:__________ Center radial:__________
Left rear: Inner lateral:__________ Center radial:__________
Right front: Inner lateral:__________ Center radial:__________
Left front: Inner lateral:__________ Center radial:__________
Mounting surface runouts (max. 0.005 in (0.127 mm))
Flange, right rear:__________ Hub, right front:__________
Flange, left rear:__________ Hub, left front:__________
Wheel stud runouts (max. 0.008 in (0.203 mm))
Flange, right rear:__________ Hub, right front:__________
Flange, left rear:__________ Hub, left front:__________
List Additional Repairs, If Applicable
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