This article defines the key parameters describing the static properties of tires and the methods for determining selected parameters among them—static radius and deflection, vertical stiffness of the tire, as well as the area and length of the tire contact patch. A literature review examined existing mathematical models for predicting tire stiffness and contact patch size. The authors then present the methodology and results of their own investigations on the aforementioned tire parameters for three sizes (165/80R14; 195/65R15; 205/55R16) under varying inflation pressures (0.1 to 0.3 MPa) and static loads (1 to 5 kN). The research yielded characteristics of changes in tire vertical stiffness, contact patch area and length, and static deflection as functions of pressure and load. The article also analyzes a catalog of tire tread footprints to understand changes in contact pressure with varying inflation pressure and vertical load. Based on the research results and analysis of modeling methods, the authors propose models to estimate the investigated characteristics and assess their accuracy. The presented results have a twofold value. They provide source data on the tested tires and propose models with sufficient capability to estimate the variability of measured parameters describing the static properties of tires as a function of inflation pressure, vertical load, and geometric dimensions.