Tire design and objective tire characterization vs manufacturing design and process

Pirelli is the 7th largest tire manufacturer in world, particularly devoted to high value tires where it is leader in prestige tires with more than 50% of market share in the Original Equipment channel, constantly engaged in the development of innovative products. This study is inserted in the research and development activity of the company and it is aimed at the experimental evaluation of the design/process leverages able to modify the tire performance. This thesis work in particular deals with effects of the cap strip layer in controlling 6 tire characteristics: high-speed behavior, final product dimensions and tolerances, tire stiffness in the 3 directions (radial, longitudinal and lateral), breaking energy, rolling resistance, contact patch dimension, shape and pressure distribution. The cap strip is currently used as a mean to contain the tire expansion in high-speed conditions where the centrifugal forces tend to deform the tire, the other five characteristics represent other possible influences on the finished product which might be influenced by the cap layer design leverages. The analysis is performed by evaluating the correlation between the cap layer characteristic and the experimental results obtained from a series of test on tire prototypes appositely created to this purpose. The takeout of the analysis is then evaluated in its statistical consistency, and in its coherence with the current knowledge, comparing the outcomes with other studies and/or proposing new explanations to the phenomena observed. Finally, the impact of each design and process leverage is assessed in feasibility and goodness in controlling each of the above-mentioned tire characteristics, providing a useful knowledge which might be used to counteract tire problems during the development phase and further improve the tire performances.