Tire-Rim Mismatch Explosions: Human Factors Analyses of Case Studies Data

Data from 13 accidents involving mismatches of 16 inch tires and 16.5 inch rims were analyzed. These mismatches resulted in tire bead failures during inflation that caused the assembly to explode leading to serious injuries and deaths. The data indicated a number of consistent findings. In ten of the accidents an “entrapment” situation existed in which the person inflating the tire and subsequently injured was not the person who selected the components and placed the tire on the rim. While there was great variance in training, experience and knowledge of tire busters, virtually all were unaware of this mismatch hazard. Tire busters typically did not look for size information on rims, and such information was either not displayed or displayed poorly. Regarding task feedback, because the outer flange diameter of the 16 inch and 16.5 inch rims are virtually the same, placing the tire on the 16.5 inch rim did not provide feedback that something was wrong due to greater task difficulty. Also, the fact that the tire did not properly seat was not attributed to a size mismatch but rather to other more common seating problems. Efforts to warn about the mismatch hazard on the products have not met warnings design criteria and generally have not been effective.