Traditionally commercial and industrial vehicle wheel nuts are tightened in two stages - first (for speed) they are 'run up' with an impact wrench and then revisited with a torque wrench to check they are correctly tightened. This method is notorious for torque inaccuracy, ask yourself -

1. How can I be sure that the air pressure settings are correct and not delivering inadequate or excessive torque, resulting in under-tightened or over stressed wheel studs?
2. Does the fitter use a torque wrench - and is it calibrated
3. Does the contract fitter have length dependency awareness regarding torque wrench use?
4. Is the tightening sequence correct?
5. Are the wheel nuts already tighter than the torque wrench setting?

As the vehicles re-enter service and clock up road miles these already over-strained or under-tightened studs are further subjected to road stresses - heavy breaking, cornering, curbing, potholes and other surface irregularities. The ultimate combination of forces is enough to cause the studs to yield or shear resulting in catastrophic detachment.

According to the Department for Transport "Careless torque costs lives" (1997), its report, prepared in 2006, found that thousands of loose or missing wheel nuts, and hundreds of wheel detachments, are caused by inappropriate process, incorrect sequence, insufficient wheel stud maintenance, contract fitter ignorance, and tooling inaccuracy.

Are you worried about the integrity of your vehicle wheels, the safety of your drivers and other road users?

Download our free information sheet and contact W. Christie to discuss a demonstration that will show you how to solve the problem.