17NA170

Bulletin No.:
Service Bulletin
Date:
17-NA-170
January, 2019
INFORMATION
Subject:
Information on Hunter Road Force Balancer
Brand:
Model:
All
GM
Passenger
Cars and
Trucks
(includes
Medium
Duty)
Model Year:
VIN:
from
to
2000
2019
Involved Region or Country
from
to
Engine:
Transmission:
North America and N.A. Export Regions
Information
Hunter Generation 3, 4 and 5 Balancers
Effective February 2017 (May 2017 for Canada), a
Generation 3, 4 or 5 Hunter Road Force Balancer is
designated as Essential Dealer Equipment. The Hunter
road Force Balancer is required to be utilized for all
repairs requiring balance and Road Force
measurement (see list of Labor Operations below). No
other wheel balancer will be considered an acceptable
substitute in GM Dealers. The Hunter Road Force
Balancer allows technicians to perform a static balance
and to check Road Force during a single measurement.
With the use of the Hunter Road Force balancer,
technicians can be sure that the tire/wheel assembly
meets or exceeds GM specifications prior to mounting
the assembly back onto the vehicle. This ensures that
problem(s) can be corrected early in the process. This
prevents repeat repairs and customer dissatisfaction in
ride quality.
The Hunter Road Force Balancer was developed over
17 years ago. Currently, the Generation 5 is the latest
version available. Any dealer having a Generation 3, 4
or 5 balancer meets the GM requirements. Generation
1 and 2 balancers are not capable of properly
measuring and correcting all GM assemblies.
GSP9722
(Generation 3)
4794706
Copyright 2019 General Motors LLC. All Rights Reserved.
Up to 8 Years Old
180 Match Mount process
available
Ability to Measure and Correct
up to 22” assemblies
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January, 2019
Road Force Touch
(Generation 4)
Bulletin No.: 17-NA-170
Up to 3 Years Old
Introduces Touch Screen
180 Match Mount process
available
Handles assemblies up to
175 lbs, 40 in tire/30 in rim
Launched February 2016
Touch Screen
180 Match Mount process
available
Handles assemblies up to
175 lbs, 40 in tire/30 in rim
Integrated Power Wheel lift –
prevents damage to mounting
shaft
SmartScan laser measuring
system - Eliminates
measurement arms
Built-in HD video tutorials
Weight placement laser and
work light
Color Printer with storage
BulllsEye dual-taper 10 collet
center kit
4794718
Road Force Elite Balancer
(Generation 5)
4794731
Why is the Hunter Road Force Balancer
Needed?
Today’s cars and trucks have many advanced braking
and stability systems. All of these help with better
braking and control of the vehicle. Additionally, stricter
fuel economy standards are driving many innovations
to meet these new standards including lower rolling
resistance tires with a decreased contact patch. To
meet these requirements, suspension systems and
tires are getting stiffer and many of todays tire/wheel
assemblies can weigh as much as 80 lbs (36 kg). We
are also seeing a customer trend for larger wheels in
sizes of 20” and 22.” Because of this, having properly
balanced wheel/tire assemblies and low Road Force
tires readings are essential to ride quality. Only by
using the Hunter Road Force Balancer will the
technician know that the tire/wheel assemblies meet
the GM specifications prior to mounting them back on
the vehicle.
What Produces Road Force?
To understand the effects of radial force variation,
imagine the tire as a collection of springs between the
rim and the tire tread. If the “springs” are not of uniform
stiffness, a varied force is exerted on the axle as the tire
rotates and flexes. This creates a vibration in the
vehicle. (Hunter Engineering)
Vibration Source From Radial Force Variation
What is Road Force?
Previously, tire/wheel assemblies were measured for
“static balance.” This allowed for weights to be placed
on the inside and outside of the wheel flange/rim
surface. While this is the first step, todays vehicles also
need the Road Force checked. Road Force is a
measurement of both sidewall stiffness and how much
the assembly is “Egg Shaped.”
4794771
The Hunter Road Force Balancer has the ability to
measure this variation. By measuring, correcting and
validating the Tire/Wheel Assembly is in spec for both
Bulletin No.: 17-NA-170
January, 2019
static and Road Force, the Technician can be assured
that the tire/wheel assembly is correct prior to mounting
it back on the vehicle. Excessive Road Force can also
be produced by incorrect tire mounting or improper
bead seating to the rim. Both of these will provide a low
and/or high spot in that area. This can occur on either
the inside or outside flange. By measuring the Road
Force, the Hunter is able to identify a problem before
the tire/wheel assembly is mounted back on the
vehicle.
Hunter Road Force Balancer for Correcting
Customer Complaints
Many of todays GM vehicles have a new design wheel.
These new wheels have removed the machined flange
that previously would have allowed for the traditional
“bang-on” weights. This was removed for aesthetic
reasons but has also driven the need for changes in
balancers. Modern balancers need to account for this
by allowing wheel weights to be placed on the inside of
the wheel. Additionally, the previous method of
“vectoring” or “Match Mounting” a tire cannot be utilized
since the starting point is to measure the wheel runout
using measurement arms. To address this concern,
Hunter has developed the “180-Match Mount” process
( https://www.youtube.com/watch?v=_RdmL4-uHh0).
This process allows a more precise measurement and
correction to the Tire/Wheel Assembly by using the
Road Force measurements to determine proper
alignment of the tire to the wheel which produces the
lowest Road Force. See the section below titled “180
Matching with Flangeless Wheels (Hunter machine)” for
more information.
Centering Check
Centering Check is an inspection and verification of the
wheel’s mounting to the balancer. It is used to identify
possible centering errors. These errors can occur with
debris or wheel mating surface damage. Both of these
can affect the measurement process. The Centering
Check procedure identifies these problems prior to
performing the balance and Road Force measurement.
If an error occurs during the procedure, an error popup
will appear with text explaining the error. The Centering
Check must be performed on all assemblies to prevent
inducing errors in the process.
Page 3
Measuring Wheel Runout and Assembly Radial
Force Variation/180 Matching Procedure
(Hunter)
Important: The completed worksheet must be
attached to the hard copy of the repair order.
To access the Vibration Diagnostic Worksheet, Go
to > Global Connect > Service Forms > General
Information > Vibration Diagnostic Worksheet.
• Measure radial force variation and radial runout.
• Record the radial force variation (RFV) on the
worksheet. It may be of benefit to have the lowest
RFV assembly to the front left corner.
• Flangeless wheels are commonly used today and
the runout cannot be measured accurately with
the tire on the wheel. There is no machined
surface on the outside of the wheel like on the
flanged wheel so for an accurate runout
measurement, the wheel should be dismounted
and a reading should be taken on the inner bead
seat area of the wheel or the (Hunter) 180
Matching procedure can be used (see below). The
runout spec is the same as a flanged wheel.
Page 4
January, 2019
Bulletin No.: 17-NA-170
4540628
Legend
(1)
Flangeless Rim
180 Matching with Flangeless Wheels (Hunter
machine)
On flangeless wheels, the 180 Matching procedure can
be used when using a Hunter 3rd, 4th or 5th generation
machine. This can be used with the tire still on the
wheel.
(2)
Flanged Rim
Hunter 180 Matching Procedure (this information can
also be found in the Hunter manual for your machine):
Bulletin No.: 17-NA-170
January, 2019
Page 5
4540494
•
180 Matching will minimize Road Force® in the
tire and wheel assembly. It requires a tire changer,
as the tire will be repositioned about the wheel
during the procedure. The 180 Matching
procedure can be launched by touching the Road
Force® button, then Procedure and then 180
Matching buttons.
4540495
Page 6
January, 2019
There is a progress bar at the top of the screen to show
how far along the procedure has progressed.
1. Mount the assembly on the balancer.
2. Set the tire pressure to the vehicle manufacturer’s
specification.
3. Lower the hood to start the Road Force®
measurement.
4. Position the valve stem at 12:00 and touch “Enter
Valve Stem.”
5. Mark the tire with a piece of chalk or a marker with
a “V” opposite the valve stem as indicated. Touch
“OK” or tap the foot pedal when completed.
6. Use a tire changer and rotate the rim 180 degrees
relative to the tire, aligning the “V” mark with the
valve stem. Mount the assembly on the balancer.
Position valve stem at 12:00 and press “Enter
Valve Stem.”
7. Lower the hood to start the Road Force®
measurement.
8. After the final spin is completed, make marks on
the tire and rim as shown on screen and
ForceMatch® the assembly.
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
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) at 89 km (55 mph) or more prior to measuring.
Tire pressure must also be adjusted to the usage
pressure on the vehicle's tire placard prior to
measuring.
Bulletin No.: 17-NA-170
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 trueing 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.
Bulletin No.: 17-NA-170
January, 2019
Page 7
Road Force Data and Plots
4794816
The Hunter Road Force Balancer allows technicians to
review the Road Force Data and Plots that were
measured. This allows technicians to determine the
high and low spots on the tire. These should be used
for a visual inspection when looking for defects or signs
of road hazard damage.
To Access the Video Player:
Documentation Requirements
The labor times for balancing have been updated to
allow additional time for performing the 180 Match
Mount process on any assembly/assemblies that do not
meet the GM Specification. The additional time must be
substantiated. For any assembly requiring additional
time to perform the Hunter 180 Match Mount, a printout
showing the out of specification assembly, must be
attached to the Repair Order.
While the above information provides a summary of the
Hunter Road Force tool, all users should review the
Hunter Road Force User Manual for complete
instructions on using the machine. Additionally, the
Hunter Road Force Balancer has been integrated into
the GM Training curriculum.
Hunter Help
Hunter has also included built in videos for many of the
bulletin processes. The Video Player feature provides
tips and procedures for using the Road Force® Elite
GSP9700.
4794860
From the main balance screen, touch the “Help” button
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January, 2019
Bulletin No.: 17-NA-170
4794846
Touch the “Launch Video Player” button.
4794883
The main video menu screen is displayed.
Select a topic from the menu to view the video.
Bulletin No.: 17-NA-170
January, 2019
Page 9
4794935
The selected video will begin playing.
Labor Operations Requiring the Use of
the Hunter Road Force Balancer When
Addressing Tire Issues
Labor Operation
Description
Labor Time
8080108*
Perform Road Force Measurement
Refer to the latest version of
PI1354
8060272
Tire and Wheel Balancing - Four
8060212
Tire and Wheel Balancing - One
8060292
Tire and Wheel Balancing - Six
8060213
Tire and Wheel Balancing – Two
8069939
Tires and Wheels - Customer Concern Not Duplicated (CCND)
8060400
Wheel Replacement
8060650
JK Tyre/American Cargo Tire Replacement
8060540
Bridgestone/Firestone Tire Replacement
8060460
Continental/General Tire Replacement
8060440
Goodyear/Dunlop Tire Replacement
8060600
Hankook Tire Replacement
8060580
Kumho Tire Replacement
8060640
Maxxis Tire Replacement
8060480
Michelin/Uniroyal/B F Goodrich Tire Replacement
8060620
Pirelli Tire Replacement
8060420
Tire Replacement
Use Published Labor
Operation Time
Page 10
January, 2019
Bulletin No.: 17-NA-170
Labor Operation
Description
Labor Time
8060680
Tire Valve Stem Replacement
8050190
Tire Pressure Indicator Sensor Replacement
8059949
Tire Pressure Monitoring System - Customer Concern Not
Duplicated (CCND)
0040272
Tire Promotion
0522150
Accessory Tire Replacement
0520130
Spare Tire Replacement
0520140
Tire Air Compressor Replacement
0512152
Accessory Tire Package Installation
0510132
Spare Tire Kit Installation
0510142
Tire Air Compressor Installation
*This is a unique Labor Operation for Bulletin use only.
Notice: To access the Vibration
Diagnostic Worksheet, Go to > Global
Connect > Service Forms > General
Information > Vibration Diagnostic
Worksheet.
Version
5
Modified
July 31, 2017 – Updated Information section to add Canada effective date.
May 29, 2018 – Added the 2019 Model Year, updated Information and added a Labor
Operation table.
October 3, 2018 – Added Labor Time information for Labor Operation 8080108 Perform
Road Force Measurement.
January 23, 2019 – Removed the Vibration Diagnostic Worksheet tables and included
instructions to access the Vibration Diagnostic Worksheet.
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.
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