A TIGHT HOLD Loss of clamp load leads to movement between the clamped parts in the joint, causing rotation and loosening of the wheel nut
Industrial products provider BMG’s comprehensive portfolio of Nord-Lock bolt securing products, includes robust wheel nuts, designed to safely secure wheel joints on both on-road and heavy-duty vehicles – even under severe conditions.
“Safe wheel assemblies rely on a high clamp load. Loss of clamp load leads to movement between the clamped parts in the joint, causing rotation and loosening of the wheel nut. This results in unbalanced wheels and wheel detachments, which are dangerous and costly,” says BMG fasteners business unit manager Maryna Werner.
She adds that, conventional wheel nuts lack a locking function and can therefore rotate loose – especially on poor road conditions and also as a result of high vehicle speed. “Wheel detachment is also caused by inadequate tightening techniques and joint relaxation, as well as thermal expansion and contraction of wheel bolts.”
The Nord-Lock wheel nut, which uses tension instead of friction to secure bolted joints, offers a reliable solution to wheel nut loosening. This system does not rotate loose and safely secures the wheel joints on roads and in harsh off-road operating conditions.
“This reliable system not only prevents accidents, personal injury and property damage, but also avoids unnecessary costs that result from unbalanced wheels, increased tyre wear and spare parts replacement,” Werner adds.
The Nord-Lock wheel nut is based on the same principle as the Nord-Lock bolt securing system, maintaining a high clamping force, even under extreme conditions. Each nut incorporates a pair of captivated washers with cam faces on one side, where a cam angle ‘α’ is greater than the thread pitch ‘β’.
On the opposite side are radial teeth. When the wheel nut is tightened, the teeth of the Nord-Lock washers grip and lock the mating surfaces, allowing movement only across the cam faces. Any rotation of the wheel nut is blocked by the wedge effect of the cams.
Nord-Lock wheel nuts are designed for use on flat-faced steel and aluminium rims. Sliding always occurs between the nut and the upper washer during tightening and between the cam faces during untightening. In this way, clear impression marks are created, without scoring the contact surface. On reuse, the serrations find their way back into the previously created impressions.
Nord-Lock wheel nuts are reusable, but before reuse, BMG recommends that nuts and wheel studs are inspected to ensure that the threads are free from particles and are undamaged.
This system, which is manufactured from high-quality steel, is prelubricated to ensure uniform friction and accurate preload during tightening. Lubrication also prevents corrosion and therefore extends the service life of wheel studs.
Nord-Lock wedge-locking technology has been used in diverse applications for over 30 years, to ensure the structural security of bolted applications exposed to strong vibrations and high dynamic loads.
BMG’s extensive range of quality branded fasteners also includes bolts and nuts, rivets, screw products and socket screws, washers, threaded rods, anchors and Super-Bolt lock bolts.