Reprint from Hardware & Fastener Components Magazine, Vol. 44

Several days before Christmas of 2016, a truck driver was passing through Chicago on one of the primary expressways. All of a sudden he noticed a large obstruction in his path and swerved his truck to miss it. Unfortunately, in this maneuver he clipped an adjacent vehicle sending him out of control, flipping his truck on its side, breaking through the center concrete divider, and hitting an on- coming vehicle. Sadly, the truck driver lost his life in this tragic accident.

Accident scene investigators would later determine that this accident was triggered by a wheel that had separated off of another truck and was lying in wait on the roadway for an unfortunate victim. In answer to a spate of such incidents, in 1992 the United States National Transportation Safety Board (NTSB) sponsored a study to examine the cause and frequency of wheel separations from large Class 8 trucks. Shockingly the study determined that there are between 750 and 1050 such reported separations on U.S. roadways every year. That amounts to two to three every day. The study went on to find that the leading cause of such separations was improper nut and stud tightening during the installation or reinstallation after maintenance of large truck wheels.