The Goodyear & Tire Rubber Company

Thierry Koeune

Bernard Croissant

Romain Kunsch

Edouard Michel

Ren&eacute; Bormann

The invention relates to methods for improving vehicle steering performance and robustness of that performance through control of non-uniformities in the vehicle's tires, wheels and tire/wheel assemblies as a way to overcome the tendency of many vehicle types to undergo &ldquo;steering performance loss.&rdquo; While minimizing lateral force variations (e.g., couple imbalance), a controlled amount of radial and/or tangential force variation is induced in one or more tire/wheel assemblies by means of mass non-uniformity, dimensional non-uniformity, and/or stiffness non-uniformity. For mass non-uniformity, the preferred method includes imparting a controlled amount of excess mass to tires, especially in the tread region, by means, for example, of a heavy splice, an extra fabric piece, or a sector of a tire component having excess mass. The excess mass is meridionally symmetric so as to induce static but not couple imbalance, thereby imparting a &ldquo;residual static imbalance&rdquo; (RSI) to the tire. Beneficial tangential and/or radial force variations will result in the use of such a tire, even if the tire/wheel assembly is balanced by weights added to the wheel. A method of determining steering performance robustness for a vehicle/wheel/tire construction combination comprises conducting a series of steering performance tests of the vehicle, wherein at least one of the tire/wheel assemblies has its balance condition changed for each test through a progression of values from values favorable to steering performance (e.g., RSI), through neutral values (balanced), to values unfavorable to steering performance (e.g., couple imbalance).

Method of improving steering performance robustness utilizing mass non-uniformity in tire/wheel

Methods for improving vehicle steering performance and robustness of that performance include control of non-uniformities in the vehicle's tires, wheels and tire/wheel assemblies as a way to overcome the tendency of the steering systems in certain vehicle types to undergo &ldquo;steering performance loss.&rdquo; While minimizing lateral force variations (e.g., couple imbalance), a controlled amount of radial and/or tangential force variation is induced in one or more tire/wheel assemblies by means of mass non-uniformity, dimensional non-uniformity, and/or stiffness non-uniformity. For dimensional non-uniformity, the preferred method is to impart a controlled amount of dimensional non-uniformity (preferably radial runout) to the tire and/or the wheel in at least one of the tire/wheel assemblies, followed by statically and dynamically balancing all of the vehicle's tire/wheel assemblies. Preferably, all imparted tire non-uniformities are distributed meridionally symmetrically about the equatorial plane of the tire/wheel assembly.

Method of improving steering performance robustness utilizing dimensional non-uniformity in tire/wheel

Methods for improving vehicle steering performance and robustness through control of non-uniformities in the vehicle's tires, wheels and tire/wheel assemblies. While minimizing lateral force variations (e.g., couple imbalance), a controlled amount of radial and/or tangential force variation is induced in one or more tire/wheel assemblies by imparting mass non-uniformnity, dimensional non-uniformity, and/or stiffness non-uniformity. The tire non-uniformities are preferably distributed meridionally symmetrically about the equatorial plane of the tire, so as to induce tangential and/or radial force variations but not lateral force variations. Beneficial tangential and/or radial force variations will result from the operation of such a tire, even if the tire/wheel assembly is balanced by weights added to the wheel. The stiffness non-uniformity is preferably imparted in the tire by one or more heavy splices, and/or extra pieces of fabric applied to the carcass or tread, and/or sectors of tire components having different stiffness.

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Fauvillers, Belgium

Thierry Koeune