The DISC-LOCK principle was developed by Scotsman, Alistair McKinlay, in response to the growing problem of wheel loss from moving trucks, buses and trailers. Its revolutionary design has resulted in a safer and more reliable wheel nut than ever before and has been heralded as the most innovative development in wheel nut design since the 1930s.

2. Where are DISC-LOCK Safety Wheel Nuts manufactured?

DISC-LOCK Safety Wheel Nuts are manufactured under license in Taiwan and Detroit, Michigan, U.S.A.

3. How does the DISC-LOCK Safety Wheel Nut work?

The DISC-LOCK Safety Wheel Nut is split into two sections, both of which have interlocking rising cams, which are joined together to form one assembly. When subject to vibration or road shock the interlocking cams of the wheel nut attempt to rise against each other. As the angle of the cams is greater than the pitch angle of the thread on the stud the DISC-LOCK Safety Wheel Nut locks and will not come loose.

4. What are the chances of losing a wheel if DISC-LOCK Safety Wheel Nuts are fitted?

The chances of ever losing a wheel from a moving commercial vehicle when fitted with DISC-LOCK Safety Wheel Nuts, assuming the nuts have been fitted correctly and are in working order, are significantly reduced.

5. Can we fit half of the studs with DISC-LOCK Safety Wheel Nuts and half with conventional wheel nuts?

No, to ensure that the wheel remains secure DISC-LOCK Safety Wheel Nuts must be used in full sets.

6. Which systems can be fitted with DISC-LOCK Safety Wheel Nuts?

All hub-piloted systems can be fitted with DISC-LOCK Safety Wheel Nuts. In fact the DISC-LOCK Safety Wheel Nut fits 90% of all commercial vehicles, trailers and buses, as well as most agricultural vehicles.

7. What about conical wheel systems?

The DISC-LOCK Safety Wheel Nut cannot be used on conical wheel systems or the DIN spherical system.

8. Can the DISC-LOCK Safety Wheel Nut be re-used

Yes, the DISC-LOCK Safety Wheel Nut can be re-used, but before refitting it should be inspected in the same way as one would inspect any wheel nut before reuse.

9. Does the DISC-LOCK Safety Wheel Nut require a different torquing to conventional wheel nuts?

The DISC-LOCK Safety Wheel Nut should be torque to axle manufacturer’s instructions for torque settings. However, DISC-LOCK recommends its nuts are torqued to 500-550 Ft. Lbs. on M22 and 7/8" nuts in order to achieve optimum clamping force.

10. Does the DISC-LOCK Safety Wheel Nut maintain a 'torque tension' relationship?

Yes, because of the special locking feature of the DISC-LOCK Safety Wheel Nut it always maintains a 'torque tension' relationship.

11. What material is the DISC-LOCK Safety Wheel Nut made from?

The DISC-LOCK Safety Wheel Nut is manufactured from 1045 steel, heat treated to Rockwell C 28-32 and coated with Geomet.

12. Does the DISC-LOCK Safety Wheel Nut have a special coating

Yes, the DISC-LOCK Safety Wheel Nut is coated with an anti-corrosion coating - Geomet which has passed a 720 hours salt spray test.

13. Is the DISC-LOCK Safety Wheel Nut corrosion resistant?

Yes, the DISC-LOCK Safety Wheel Nut exceeds industry standards for corrosion resistance.

14. How is the DISC-LOCK Safety Wheel Nut fitted?

An M22 DISC-LOCK Safety Wheel Nut (most common size) is fitted with a six point M38 socket which must be placed over the entire wheel nut when fitting or removing. An instruction leaflet is provided with each order of DISC-LOCK Safety Wheel Nuts or can be obtained from the DISC-LOCK office free of charge (email info@DISC-LOCK.com).

15. Do you need to re-torque the DISC-LOCK Safety Wheel Nuts after installation?

Yes. This is very important. All wheel nuts require re-torquing after approximately 80km/50 miles or 30 minutes standing time to ensure the torque tension relationship is maintained.

16. Do you need a torque wrench when fitting DISC-LOCK Safety Wheel Nuts?

Yes, when fitting any wheel nut a torque wrench should be used to check that the axle manufacturer's recommended torque settings are achieved (or DISC-LOCK’s recommended torque of 500-550 Ft. Lbs.).

17. Can an air-gun be used when fitting DISC-LOCK Safety Wheel Nuts?

Yes, however, should an air-gun be used: "Final tightening (of wheel nuts) must be with a calibrated torque wrench set to the vehicle manufacturers' torque value. Air impact tools and extensions to wheel braces should not be used for final tightening."

18. Can an air-gun be used when removing DISC-LOCK Safety Wheel Nuts?

Yes, an air-gun can be used when removing the DISC-LOCK Safety Wheel Nut. In addition, it is important to remember to place the air-gun socket over both hexes of the wheel nut.

19. Should the wheel stud be lubricated with oil before fitting the DISC-LOCK Safety Wheel nut?

Yes, two drops of oil should always be added to the wheel stud before fitting the DISC-LOCK Safety Wheel Nut. This not only prolongs the life of the threads, but also helps to achieve the proper torque tension relationship.

20. Is the DISC-LOCK Safety Wheel Nut acceptable for use on aluminum wheels?

Yes, experience in the U.S. and Canada indicates no problem with galvanic corrosion between the DISC-LOCK Safety Wheel Nut and alloy wheels. The DISC-LOCK Safety Wheel Nut is fully approved in all sizes for use with alloy wheels providing the wheel nuts have been fitted correctly and the recommended torque has been applied.

21. Is the DISC-LOCK Safety Wheel Nut patented world-wide?

Yes, the DISC-LOCK Safety Wheel Nut is patented world-wide.