Paper Number 4.2
UNIFORMITY: A Crucial Attribute
Of Tire / Wheel Assemblies
Marion G. Pottinger
Owner, M’gineering, LLC
Voice: (330) 666-8587
Email: mpottinger@roadrunner.com
Good ride, acceptable comfort for passengers,
is a required attribute for all road vehicles particularly automobiles and
light trucks. The tire / wheel assembly is a critical component in
providing good ride. Indeed, obtaining good ride was the crucial factor
that drove the invention of and rapid popularization of the pneumatic
tire. Today, the ride effect of tires is often thought of in two
ways. The first is in terms of the transmission of vibration produced by
the interaction of the tire with road surface irregularities, harshness.
The second is in terms of tire structural irregularity generated energy
transmitted during operation on a smooth road, uniformity. Both types of
energy share the dynamic properties of the tire structure though they differ in
source. This paper concentrates primarily on uniformity induced vibration
particularly at the frequency of tire rotation, but does touch on harshness to
a small degree, when the sharing of structural dynamics makes it appropriate.
This review of the subject of force uniformity includes the effect of wheels,
as wheels contribute to the vibration that reaches the vehicle spindle.
Balance is touched on only as it affects force uniformity in well-balanced
assemblies. This is not a treatise on balancing. A suggestion is
made, which should, if practical, improve the installed uniformity of
tire/wheel assemblies.