Wheel nuts and bolts

There are a number of fundamentals when it comes to your overlanding vehicle’s wheel nuts and bolts, says Mic van Zyl.

Over the years I have been very fortunate when it comes to tyre punctures. I haven’t had that many but my most recent one was a rather disastrous affair in the Tankwa Karoo National Park. Fully aware of the fact that I did not have the correct tyres fitted for the terrain, I paid the price next to a very hot and dusty road – twice on the same road.

This experience was exacerbated by my inability to get two of the wheel nuts undone. I eventually managed but I was quite upset with the

fitment centre for overtightening the wheel nuts and more so with myself for not practising better DIY vehicle maintenance in this area. I am now the proud owner of a very decent torque wrench and I always re-torque my wheel nuts after a visit to the tyre store.

DURING THE LOCKDOWN, I have come across a plethora of interesting information on the internet, covering a number of very diverse topics. I’ve taught myself to play the drums, and I have become much better at taking and editing photos thanks to Photoshop and other photography tutorials.

I have also come across much information on DIY vehicle maintenance which has become very relevant with our vehicles being laid up for weeks at a time. One particular piece of information struck a chord with me as it had to do with wheel nuts and DIY maintenance to prevent a Tankwa disaster.

The video in question was produced by someone with a master’s degree in automotive engineering. He says there are fundamentals when it comes to wheel nuts and bolts and I have taken the following for my own ‘toolbox’ of knowledge. First and foremost, wheel nuts or wheel bolts must always be torqued to the correct vehicle or wheel manufacturers specifications. The tightening sequence is also very important.

Vehicles that are not in constant use (dedicated overlanding vehicles, caravans, trailers and camper trailers) can develop inter-metal corrosion between the wheel nuts and wheel studs, or in some cases between the wheel bolts and the wheel hub into which they screw as well as the metal of the actual wheel. This corrosion will in most cases increase the torque required to undo the wheel.

One’s attempt to overcome this increased torque requirement can quite easily snap off the stud or wheel bolt. Should you encounter a stuck fastener, a squirt of penetrating lubricant is a good start. Then, quick sharp blows with a rubber mallet onto your wheel spanner is advised over a constant increased force. The quick, sharp blows will ‘crack’ the corrosion and prevent over-torque which is what snaps those studs.

IT IS ALWAYS a good idea to administer some preventative DIY to those wheel nuts and bolts. A slight bit of Copper Slip lubricating grease on the threaded surface of the wheel studs as well as the mounting surface between wheel nut and the actual wheel will prevent the corrosion.

It is also critical to ensure that the correct wheel nuts or bolts are used with the new wheels, especially when you have aftermarket mag wheels fitted. The mounting surface between wheel nut or bolt and the steel or mag wheel has a specific angle to allow the surface to marry perfectly. Any deviation from this will prevent correct tightening torque which could also lead to disaster.

Finally, when using Copper Slip on the wheel bolt threads, you must decrease the tightening torque accordingly. The recommendation by manufacturers is up to a 30% reduction in the fastening torque of a greased fastener.

So, according to this automotive engineer, apply a minimal amount of Copper Slip to the wheel nut or stud threads as well as the nut or bolt to wheel mounting surface and drop your wheel fastener torque from 110 Nm down to 80 Nm. Your wheels will not come undone and you will prevent any additional drama when changing a punctured tyre.