From: Eric L. Johnson [dandejohn@aol.com]
Sent: Tuesday, August 22, 2000 8:30 AM
To: 928
Subject: [928] Re: Vibration at hwy speeds

Stephen,
Locate a facility that uses the Hunter GSP9700 Vibration Control System.
Prior to spin balancing the assembly, a roller applies 700#'s of force to
the tire and checks for any inconsistancies such as low or high spots. If
a problem is noted, the machine prompts you to check the external lateral
and radial runout using the data arms on the machine. Afterword, it will
determine if the wheel, tire, or both are the problem and if the vibration
can be brought within spec. by rotating the tire on the wheel. If it
can't, it will tell you which one to replace. This machine can sense up to
4 vibrations per revolution.

I use this machine often in the course of my work. You wouldn't believe
how many brand new tires fail this test. Once it picks out a good set, the
customers are always happy.

Good luck,
Eric Johnson
1987 928S4