The Real Cost of Inaccurate Torque Output
How transportation maintenance, repair, and operations facilities can help prevent wheel runoff crashes with precision torquing.
As far back as 1992, the National Transportation Safety Board conducted an investigation into a string of fatal truck-wheel runoff accidents. “In the 3-week period alone, between October 14 and November 4, 1991, three fatal heavy truck-wheel separation accidents occurred, including an accident in which the front left wheel broke off of a two-axle cargo van truck and careened into the path of an oncoming school bus carrying 46 fourth-graders and their chaperones. The 365-pound wheel slammed through the bus windshield, killing two children and a chaperone,” stated the official document. Inaccurate bolt tightening was listed as one of the major causes of these horrific accidents. “Wheel failures involving broken studs, lugs, or loose nuts most frequently result from the improper tightening of the nuts or failure to re-tighten the nuts after the initial seating of the fasteners,” wrote the report’s authors. This problem is not new, but practical solutions are just starting to emerge.