Understanding the correct use of sleeved wheel nuts for selected axles and wheels can maintain clamp loads to retain the wheel to the axle. The safety alert illustrates the difference between the standard ISO wheel nut, and the ISO wheel nut with threaded sleeve as well as single wheel assembly mounting.

The incident or issue:

A recent case has identified that incorrect wheel nuts can easily be used to re-attach supplied aluminium wheel assemblies to steer axles on trucks. A standard ISO nut was fitted where a sleeved wheel nut should have been used. This issue can happen to anyone including experienced operators. As a result, the standard ISO nut fitted had a very limited amount of thread engagement and would not comply with the manufacturer’s recommendation nor been able to maintain clamp loads to retain the wheel axle.

Solution:

Fit the correct wheel nuts to suit both the axle and wheel assembly, tension the wheel nuts appropriately and check them after about 100 kilometres of driving from its initial installation.

Follow up actions:

• Inspect the wheel end for the correct nut. If it is unclear, remove a wheel nut to inspect. Then use the correct procedure to re-tension all nuts from loose.
• When ugrading from steel to aluminium rims, ensure the studs have adequate length to allow the stud to protrude past the end of the nut or use sleeve nuts.