Hunter GSP 9700 analyzer

[carl]

Anyone run their tires on this at a local tire shop? Its some kind of tire/wheel vibration analysis/balancer under simulated load. I had mine ran recently and they said my tires were completely off (haha what else would they say to support the claims???). ..funny, I noticed no tire issues before. I had them done for the maintenance, based on the road conditions around here. Anyway, when I left they had one neat small weight on the outside of each tire. If you dont buy tires or something this can cost up to $19 per tire for the yanking... I mean priviledge. Look for the $9.99 coupons at somewhere like CassidyTire/Suburban Tire if you have one around, its probably their standard balancer for new tire mounts at most places that have it.

[Archon]

This is GM's TSB regarding it.

INFORMATION

Bulletin No.: 00-03-10-006D

Date: November 26, 2008
Subject:
Information on Tire Radial Force Variation (RFV)

Models:
2009 and Prior GM Passenger Cars and Light Duty Trucks
2009 and Prior HUMMER H2, H3
2009 and Prior Saab 9-7X
2000-2005 Saturn L Series
2003-2007 Saturn ION

Supercede:

This bulletin is being revised to add the 2009 model year. Please discard Corporate Bulletin Number 00-03-10-006C (Section 03 - Suspension).
Important:
^ Before measuring tires on equipment such as the Hunter GSP9700, the vehicle MUST be driven a minimum of 16 km (10 mi) to ensure removal of any flatspotting. Refer to Corporate Bulletin Number 03-03-10-007C or newer - Tire Characteristics of GM Original Equipment Tires (SI Document ID #1414757).

^ Equipment such as the Hunter GSP9700 MUST be calibrated prior to measuring tire/wheel assemblies for each vehicle.

The purpose of this bulletin is to provide guidance to GM dealers when using tire force variation measurement equipment, such as the Hunter GSP9700. 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 shake on smooth roads.

Tire related smooth road highway speed shake can be caused by three things: 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 any 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.

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. Equipment such as the Hunter GSP9700 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.

Equipment such as the Hunter GSP9700 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 the Hunter, 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.

Equipment such as the Hunter GSP9700 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.

[carl]

Nice. I noticed that several dealers also have these units also. It appears to have some capabilities, but I don't know that they are utilized by local tire shops looking to make a buck on a balance job at 9.99 /tire.

[its840]

pretty sure thats the one we use at sears.. they charge like 9$ for a one time or 12$ for a one yr balance.. thats for a 15 or 16 in tire.. and goes up to like 24.99 for one time (all you can get) for anything over 22"

[dirtracr95]

I used a Road Force Balancer once when I was helping out at one of the other Just Tires. I almost broke my hand I also wasnt using the runout measuring thing right. Most shops wont use them because they are too time consuming and time is money.