This Data Item sets out, in non-mathematical terms, the reasoning that has led to the preparation of the latest set of Data Items, Technical Memoranda, and Technical Papers, which comprise the ESDU canon of publications that describe the motion of single pneumatic tyres on paved surfaces. The intention that underlies the modelling scheme developed is to produce an algebraically uncomplicated formulation for the performance of a single tyre in motion. The model sought is not for aid to tyre design.

Following modern thinking, it is supposed also, that there exists a layer of low-strength material at the interface between a hard surface and a bulk of rubber. This layer is perceived to be of molecular thickness and has mechanical properties different from, but related to, those of the “parent” rubber. It is also supposed that decelerating force consists of two independent components: adhesion and hysteresis. Furthermore, knowledge of the temperature of the surface on which a rubber compound moves is essential, not only to understanding the mechanisms involved in laying down the interfacial material, but to calculating decelerating forces.

The logic that underlies the canon is that it is founded on an algebraic, empirical, model for simple blocks of rubber just starting to slide on dry, plate glass. From that superficially uncomplicated base, a succession of arguments is used to progress to the complex case of a pneumatic tyre moving, partially braked, over a flooded runway. That runway may be finished with concrete, asphalt, or an epoxy-resin.