As part of their ambitious tire test development program, NHTSA used the proposed tire endurance road wheel test, which is a stepped-up load test, to study different tire aging protocols.
One important document entered into the Tire Aging Docket by the NHTSA Applied Research group was a file consisting of photographs of individual tires that had exhibited different failure modes as observed upon road wheel testing of used tires taken out of service, new tires of these same models, and variously new and aged tires of different brands.
In order to increase awareness, we have summarized the road wheel removal codes established by NHTSA to categorize different failure modes.