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Goodyear and Michelin formed a joint venture in June of 2000 to develop run flat technology and accelerate the introduction of innovative tire systems. With the run flat segment of the tire market on the verge of rapid growth, potentially involving a number of varied technical approaches, the need for global standards was soon recognized. The joint venture has taken the lead in the effort to establish the standards. The paper gives background on run flat tires and contrasts the widely varying service requirements in different parts of the world. Both vehicle manufacturers and consumers will benefit from these new tire system standards.

The increased popularity of MPV's (multi-purpose vehicles such as light trucks, passenger vans, and utility vehicles) during the 1980's has created an expanding vehicle market segment. These vehicles operate under a wide range of inflation and loading conditions which require all-season and off-road performance. Through the use of high technology computer-aided engineering (CAE) tools and testing methods, unique MPT (multi-purpose tire) concepts have been developed which reduce trade-offs and optimize overall tire performance.

A tire contact pressure study has been conducted to determine how different truck tire types respond to load and inflation parameters. The combination of tire type/size, loading, and inflation pressure determines the shape of the vertical contact pressure profile and the maximum contact pressure. Radial-ply truck tire contact pressures were generally higher than the bias-ply truck tire. Tire loading influenced shoulder region contact pressures whereas inflation pressure influenced center region contact pressures. The maximum level of vertical contact pressure was found to be as high as twice the tire inflation pressure.

A computer-controlled image analyzer is being used to measure tire contact areas on hydroplaning photographs. The system uses the gray level of each point on the image to determine contact. This permits the complex shapes in the tire footprint to be precisely defined.

Just as the vibration modes of a beam are dependent on its end constraints or boundary conditions, vibration modes of a tire are dependent on its patch and spindle constraints. This dependence is key to understanding the dynamic properties of a tire and is apparent in various analytical and experimental investigations in the literature. Tire Finite Element(FE) Analysis and modal test results are presented here which demonstrate this dependence. Then, the influence of tire modes in tire highway-speed uniformity testing is discussed. Finally, the importance of tire dynamics in suspension dynamics is demonstrated. A comparison is given between modal analysis of a simple suspension with a tire modal model and the same suspension with simple spring rates for the tire.

The On-Board tire sound testing technique is a research tool characterized by a near field measurement and recording of tire sound generated at the rear of the tire footprint. The measuring microphone is located directly behind the tire within the envelope of the slip stream of air moving around the tire. The test allows the continuous coast-down through the complete operating speed range, excluding the Doppler effect characteristic of the coast-by test. By presenting the coast-down results in a three-dimensional (speed, frequency, sound level) graphical manner, the speed dependent tread sound and constant frequency resonant sound can be easily recognized.

A study of the differences between the tire noise generated on the road and on a lab wheel was made using the “On-Board” testing technique. An Anechoic Chassis Roll facility was used for the lab wheel, allowing the use of exactly the same vehicle and microphone position for both tests. The only significant differences were the surface curvature and texture, and the absence of wind noise on the indoor lab wheel. Thirteen different carved designs were tested. There were basically three design types - rib, block, and lug - with varying void volume. The results of the study indicate there is good correlation in the more aggressive block and lug designs, but the quieter smooth and rib designs exhibit significant differences.

Product and materials evaluation testing has been revolutionized to meet the unique requirements of steel belted tires. Many of the classical cord and tire tests have been found to be inadequate and others to require modification. The development of many new test methods has been required. This paper discusses the tests used to characterize and evaluate steel for tires. These tests can be broadly divided into two categories: 1. Tests evaluating the steel cord material such as tensile properties and mechanical properties. 2. Tests evaluating the steel-rubber composite behavior such as adhesion and fatigue. Test parameters, data accumulation and treatment, and significance of test results are discussed.

This paper describes in general terms the major improvements in materials used in the manufacture of conventional bias angle tires. Due to the broad scope of the subject matter, detailed technical explanations in chemical terms are omitted in favor of a more general review of the type, method, and history of materials improvement. In addition, many of the materials, their requirements, properties, and contribution to tire performance are related. Some of the probable future materials trends are also included.

Present and future changes in the trucking industry have, and will, place greater significance on adequate tire inflations to meet increasing service demands. Truck tire inflation monitoring devices over the years have offered promise as one method of insuring, controlling, and maintaining tire inflations. In this connection, both low inflation warning systems and constant inflation systems have been extensively tested and evaluated.

The development of the low profile passenger tire is described. This tire provides improved handling and stability, faster cornering, improved high speed performance, and longer tread life, with no loss in noise level or riding comfort. Tire characteristics described include improved tread design and tread rubber compounding, contour shoulder, and low profile carcass. The effect of cord angle on tire inflation shape and speed are also discussed.

The overall picture of Goodyear's testing facilities at their Texas proving grounds, with particular emphasis on earthmover tire tests is presented. Most of the information on tire heat tests and the equipment involved give a new approach to this important problem. Tests can now be programmed, which will duplicate a given haul proposal, so as to determine the maximum tire heat which would develop under these job conditions. The development of the optimum earthmover tire will continue to advance as new materials are proved through new testing techniques.

SPARE TIRE elimination is a problem that has defied tire engineers for years. Because the space it occupies is wanted for other purposes, increased efforts are being applied to the search for a solution. This paper describes one approach — the dual compartment tire. This is made up of two tires, one inside the other, both of which are inflated at all tiines. If the outer tire is punctured, the inner tire supports the car until it reaches a service station. According to the author, tests indicate that this solution holds promise of eliminating the spare — if the cost can be lowered.*