Influence of Tire Core and Surface Temperature on Lateral Tire Characteristics

In investigation and development of road tires within passenger car development, temperature dependency of tire characteristics is often neglected. This research however explicitly focuses on investigation and identification of temperature dependency of tire characteristics and its interaction with other inner tire states. To this extent, a novel method using a thermographic camera for measurement of both tire core and surface temperature is used. On the basis of these measurements, the dependency of cornering stiffness, relaxation length and lateral coefficient of friction on either core or surface temperature is presented. Moreover, the effect of tire core temperature on inner pressure is investigated. By choice of appropriate operating conditions, the effects of temperature and inner pressure on tire characteristics is investigated separately. A mechanical-analytical analysis forms the basis for derivation of the relationship between material attributes and tire characteristics. Material measurements of a sample taken from the tire under investigation are performed utilizing a hydropulser test rig. The aim of this analysis is identification of rubber storage and loss moduli, i.e. material master curves. The relationship of these material attributes to tire behavior is then shown for the tire characteristics under investigation. Finally, the transferability of the presented findings regarding temperature dependency from a test rig environment to real road conditions is discussed and recommendations are made for tire and vehicle measurements.