Sidewall

A sidewall is the vertical or lateral surface of an object or structure that runs along its side from top to bottom. The term is most commonly used in two contexts: the sidewall of a tire and the side wall of a building or similar structure. In each case, the sidewall serves to enclose or protect interior components, contribute to rigidity, and bear loads or weather exposure.

In tires, the sidewall lies between the tread and the bead and forms a key part of the tire’s structure. It provides lateral stiffness, absorbs impacts, and helps maintain the tire’s shape under pressure. The sidewall carries important markings that identify the tire’s size, type, and performance characteristics, such as width, aspect ratio, construction type (radial or bias), diameter, load index, and speed rating. It may also display the maximum load and inflation pressure, the DOT code, and age information. Some tires feature reinforced or “run-flat” sidewalls, which allow a vehicle to continue to be driven after a puncture under certain conditions. Damaged sidewalls, including bulges or deep cuts, can compromise safety and typically require professional inspection or replacement.

In architecture and construction, the sidewall refers to exterior or interior walls that rise along the side of a building or structure. Exterior sidewalls form the building’s outer envelope, providing weatherproofing, insulation, and structural support, and they may be made of brick, concrete, stone, or framed materials with cladding. In masonry or cavity-wall systems, the sidewalls work with other elements to manage moisture and thermal performance. Sidewalls can also appear in other contexts, such as the vertical walls of trenches, silos, or ducts, where they delimit space and bear loads.

Overall, the concept of a sidewall centers on a vertical boundary that supports, protects, and defines the sides of a component.