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FAQ (Frequently Asked Questions)

How does the Nord-Lock wheel nut work?

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 which creates a wedge-locking effect (see illustration here). The Nord-Lock wheel nut maintains a high clamp force even under severe operating conditions. Any rotation of the wheel nut is blocked by the wedge effect of the cams.

How do I assemble Nord-Lock wheel nuts?

Place the rim over the wheel hub. Ensure that the wheel studs are not damaged. Then fit and tighten the nuts with a calibrated torque wrench at the recommended torque (see below) in a star pattern.

How much torque should be applied when tightening a Nord-Lock wheel nut?

The Nord-Lock wheel nut is designed to be tightened at the same torque as conventional wheel nuts. Tightening the Nord-Lock wheel nut with a torque of 600-650 Nm (450-500 ftlb) will result in a clamp load of approximately 200 kN (45000 lb).

Is the untightening torque different from the tightening torque?

Yes, when using the Nord-Lock wheel nut the untightening torque is generally lower than the tightening torque. During tightening, sliding occurs between the wheel nut and the serrated surface of the upper Nord-Lock washer. However, during untightening, sliding occurs between the cam faces of the washers, where friction is significantly lower. This is a valuable feature of Nord-Lock washers, as a low untightening torque facilitates maintenance and thereby reduces downtime. Because of this feature, the untightening torque cannot be used to indicate the maintained clamp load.

Can an impact or pulsating tool be used to tighten Nord-Lock wheel nuts?

Yes. However, please note that a calibrated torque wrench is a more accurate way of tightening fasteners.

Do I need to re-tighten the wheel nuts?

Yes. It is common practice to retighten wheel nuts. The Nord-Lock wheel nuts do not loose clamp load due to rotation. However, settlements occur in other parts of the wheel assembly during driving which may result in loss of clamp load. Nord-Lock therefore recommends that standard retightening procedures are maintained.

Do I need any special tools to tighten the Nord-Lock wheel nut?

No, Nord-Lock wheel nut is developed to fit standard equipment and tools.

Should the Nord-Lock wheel nuts be lubricated?

Nord-Lock wheel nuts are pre-lubricated to facilitate assembly. During reuse it is recommended to re-lubricate the threads as well as under the flange.

Do I need to change all wheel nuts to Nord-Lock wheel nuts?

Yes, in order to maintain the clamp load in the entire wheel assembly, Nord-Lock wheel nuts must be fitted to all wheel studs.

Can the Nord-Lock wheel nut be reused?

Yes. Before reuse inspect the nut and wheel studs to ensure that they are free from particles in the threads and are undamaged. Remember to re-lubricate the nuts before reuse.

Can the Nord-Lock wheel nut be used with aluminium rims?

No. Aluminium rims are thicker than steel rims. Wheel nuts that are specifically designed for aluminium rims therefore have a threaded extension. If wheel nuts designed for steel rims are used with aluminium rims, there is a risk of insufficient thread engagement.

Does the Nord-Lock wheel nut meet ELV and RoHS directives?

Yes, the Nord-Lock wheel nut fully complies with the EU directive 2000/53/EC on End of Life Vehicles (ELV) and EU directive 2002/95/EC on the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment (RoHS).

Will Nord-Lock wheel nut prevent deformation of wheel holes?

Yes. Deformation of wheel holes often occurs due to loss of clamp load in the joint. The subsequent consequence is movement between the rim and the hub. During braking and acceleration the stud makes contact with the edge of the hole which then deforms. Since the Nord-Lock wheel nut does not rotate loose and maintain a high clamp load in the joint, no movement between the rim and the hub is allowed and thereby deformation of the wheel hole is avoided.

Click here for the NORD-LOCK Bolt Securing System - Safety Washers Index page.

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