In December 2004 the Disc-Lock Safety Wheel Nut underwent a severe performance test at the Motor Industrial Research Association (MIRA) Proving Ground in Nuneaton, Warwickshire, UK.


A fully-laden semi-trailer/tractor-unit combination (weight 35 ton) was fitted with Disc-Lock Safety Wheel Nuts on the nearside and standard two-piece wheel nuts on the offside.

Over a two-day period the vehicle was driven around a figure-of-eight track to apply lateral bending movements to the wheels. In addition, repeated forward and rearward emergency braking was undertaken to induce torsonial slipping forces to the wheels. At the completion of each cycle of thirty minutes a torque check was done.  

These checks revealed no loss of torque on any of the Disc-Lock Safety Wheel Nuts at any stage.

The same could be said of the standard two-piece wheel nuts, a staggering 50% of which had come loose by the end of the test. 

To obtain a detailed copy of this MIRA Test report e-mail Disc-Lock Australasia at info@disc-lock.com.au.



Disc-Lock Safety Wheel Nuts are tested on a Junker Vibration Test machine which is named after its German designer Gerhard Junker.

Junker's theories are based in part on the so-called "long-form torque equation" relating the torque applied to a fastener to the frictional and elastic reactions to that torque.

The Junker Test machine works as follows: an eccentric cam generates a controllable amount of transverse displacement on the joint under test.  A load cell measures the actual transverse forces exerted on the joint.

One can determine the relationship between residual preload in the fastener under test and external vibratory forces created by the test machine as a function of time. 

disc-lock-independant results graph

When tested against a standard two-piece wheel nut on a Junker Test machine the Disc-Lock Safety Wheel Nut remains secure under the most severe vibration conditions while the standard two-piece wheel nut comes completely loose.