by Doug Paschall, Adel Halasa and Brendan Rodgers, Akron Polymer Solutions
The sidewall typically extends from the exterior of the bead area to the shoulder of the tire. This component in a tire has three functions;
Protect the side of the tire from damage due to curbs or other foreign objects.
Due to flexing as the tire passes through its loaded footprint, it must also demonstrate fatigue and aging resistance and protect the tire casing
Via lettering on the sidewall, provide structural information (plies, belts, load carrying capacity) and other regulatory information such as place and date of manufacture, and if needed, white strips (white sidewall), raised white letters, the tire brand or model and name of the manufacturer.
Damage resistance is provided by two means, including a high tear strength compound containing natural rubber and other compounding materials to meet the performance and design requirement; and, if needed, a scuff rib which is a rubber strip extending outwards around in the circumference in the center region of the sidewall. Wear markers can also be molded into the scuff rib, thereby enabling the vehicle operator to know when the tire may need replaced due to sidewall abrasion. Such sidewall scuff ribs can be found on city bus tires which can experience significant curb abrasion and potential damage.