yo,
Have those tires/wheel/unsprung weight stuff (such as da brake drum or rotor) been checked for balance yet?
Here is a great site on Vibes
vibratesoftware.com
For tires/wheel, rotor they refer to the HUNTER GSP 9700 wheel balancer as the diagnostic tool so look for a "reputable" tire place that uses that or an upgraded version balancer; I know that a lot of Discount Tires stores use that model.
Here is an example of the detailed info by vibratesoftware.com
Theory and Information
Excessive tire and wheel runout can cause a noticeable vibration. As the vehicle is driven, the wheels and tires are exposed to great stresses and abuse. Wheels can bend and tires can separate, the result is a vibration. This test will help determine if the tire, the wheel, or both are responsible for the vibration.
T.I.R. (Total Indicated Reading) and Harmonics
Total indicated reading - the maximum dial indicator movement (peak-to-peak) during one revolution or cycle.
Harmonic – in a harmonic measurement, both the magnitude and the duration (length) of the measured segment are used.
T.I.R. (Total Indicated Reading)
There are two types of total indicated readings:
Loaded TIR of the tire is used since it is compressible and changes under force.
Unloaded TIR of the wheel is used since it is not compressible and changes little, if any, under force.
In the past, some vehicle manufacturers have published unloaded TIR specification for the tire/wheel assembly. Total indicated readings in the tire/wheel assembly alone do not account for the duration (area) of the occurrence (bump), and can not determine the magnitude of the force as displayed in a harmonic.
The illustration below shows the limitations of using TIR for vibration resolution in comparison to First Order Tire Speed related vibration harmonic (R1H) measurement. The TIR is .040” in both examples, but the durations are not the same and therefore the harmonics will have different effects and completely different values. The example below may have the same TIR but the T1 harmonic could be 80 pounds of R1H harmonic force on the left versus 5 pounds of R1H force on the right.
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So look thru all their Diagnosis Routines..print tem out and visit the places that used the Hunter... see if they understand some of the basic checks..if they look kinda x eyed or too busy to discuss it; move on to next place.
\Find out where the trucker's go for tires that use the Hunter... they usually know who does qual. work.
they also address many other sources; such as;
Propshaft speed related vibrations are generally caused by a component rotating the same speed as the propshaft
First order propshaft speed related vibrations cause one shake or disturbance for each revolution of the propshaft. On standard 4-wheel drive or all-wheel drive vehicles, don't forget that the front propshaft can also cause this same type of vibration. Shift the vehicle in and out of four-wheel drive in an attempt to verify and isolate the concern.
Note: Some vehicles equipped with an automatic transfer case can still have the front propeller shaft rotate in two-wheel drive; however, it will not rotate at the same speed as it normally would in four-wheel drive. Shift the vehicle into four-wheel drive during diagnosis to eliminate the this potential diagnostic problem.
The following diagnostics apply to front and rear propshafts.
IMPORTANT: Anything that is out of balance will only cause a first order vibration, never any higher order vibrations.
NOTICE: The following items should be checked in the order shown.
First order propshaft vibrations are usually caused by:
A component rotating the same speed as the propshaft that is out-of-round. - click here to diagnose.
A component rotating the same speed as the propshaft that is out-of-balance. - click here to diagnose.
Drive axle problems. - click here to diagnose.
propshaft should rotate on it's axis while the vehicle is moving. If there is runout in the propshaft or what the propshaft is connected to, the propshaft will orbit rather than rotate. This can cause a vibration which typically can be felt and heard. Propshaft runout should always be checked before attempting to balance the propshaft. Propshaft runout can be caused by a number of items including: transmission output shaft, transfer case output shaft, pinion ******, pinion gear, etc.
Spline Vertical Endplay Setup Procedure
Raise the vehicle on a suitable hoist allowing the wheels to spin freely
Attach a dial indicator with a magnetic base to the underbody close to where you will be measuring runout.
Spline Vertical Endplay Measurements
Check for excessive vertical play in the splines of the slip yoke, by pushing up and pulling down on the slip yoke while watching the dial indicator.
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and so on.
GL!
