"TRICKING A TORQUE WRENCH"
When it comes to applying the proper force to installing wheels on highway trucks and trailers, the torque wrench has become a valuable tool. When I started working in the tire industry, the method of installing wheels was to tighten them with a 1" impact until they would not turn any more. That made them tight.
What we didn't know was that to get proper tightness, the bolt needs to stretch slightly but be able to relax when the pressure is removed.by loosening the wheel nuts.
A properly calibrated torque wrench set to the proper torque value will alert the technician installing the wheels, that the torque value has been reached.
There are many things that can "trick" a torque wrench.
1. Applying oil where the torque setting requires dry torque.
2. Not applying oil where the torque setting requires oil.
3. Using Anti-Seize material on any nut or bolt fastener.
4. Not properly cleaning the mating surfaces of oil, dirt, rust or other debris.
5. Applying additional force after the torque wrench has clicked.
6. Adding an extension bar or snipe to the end of the torque .wrench.
7. Using more than one extension on the end of the torque wrench.
Properly installing wheels on highway trucks and trailers requires trained people who will diligently follow proper practices and procedures.