Nissan Patrol Wheel Studs

I am not sure about GU patrols but having wheels come off is more common occurrence than you would think with larger diameter wheels. I have had a 4x4 trailer wheel come off - with snapped studs. I was the last person to do them up so no-one to blame.

As for tightening - tyre shops all have changed their practice of 10 years ago of smashing rims on with air ratchet drivers. They will run the nuts off and on with the air guns but the final tighten is with a hand wrench. This is for two reasons - firstly not to overtighten the nut and secondly so as to not damage the stud. There where lots of incidents where customers could not undo their wheel nuts and other incidents where the studs were sheered off from being too tight.

Steel rims have the advantage of the counter sunk nut holes that are also spring loaded in that where the nuts go on is elevated off the hub by millimetres so when tightened it is spring loaded. Alloy rims have the advantage of running truer, looking better and not rusting. Unfortunately the wheel nuts need to be of a different configuration relying on tensile force of the studs to create the spring load. The later cars are upsizing their wheel studs to allow for this force.

I would like to add I am no expert and this is only my opinion from street learning.

Cheers

Serendipity

I have a 2010 ST that has nut indicators on it. If the wheel nuts are not seated properly and undertentioned you may lose a wheel. Nissan are aware of this problem that's why the nut indicators are a genuine Nissan part.

Cheers

Nissan have certainly had the bad press but seen it happen commonly on 6 stud toyotas too. All the tyre dealers I've dealt with in recent years use torque wrenches to tension the nuts. I also think the 12mm studs are too small - my wife's VW uses 14mm nuts as do the more recent Landcruisers.

I carry a torque wrench and check the nut tension before I leave and every few days when I'm away. Also retension the nuts a few hundred kms after the wheels have been taken off for any reason.

It also helps if your wheels are hub centric - the centre of the wheel is a tight fit on the hub. Most factory wheels are good in this respect - many aftermarket wheels are not - not sure about Patrol mags.

Wheels fall off 4WDs all the time - it's not a 'Nissan' or a 'Toyota' or a 'D-Max' thing. It is not part of a 'wider problem'. Something went wrong with your vehicle, in your situation. But it's not fun, is it?!?

A loose steel wheel will fall off just like a loose alloy wheel - however some alloy wheels (partcularkly aftermarket) tend to have studs come loose more often as there is no 'spring' or 'give' in teh alloy, plus they may lack the steel insert the nuts' taper should bear against

Did the studs break? or come loose?

As mentioned by others, over-torquing of the wheel studs is often the culprit but that could have happened at *any* time during the vehicle's life with the fatigue factor only cathcing up with it now

As mentioned by others, Nissan became aware of this problem and now make available the wheel nut indicators. It is essential that the nuts are done up to the correct torque with alloy wheels, else they will come off.

It's not common for any wheel to fall and I have only ever heard of a few occasions when 4x4 rims have come adrift....... except the Nissan Patrol wheel nut issue/recall.

Most wheel issues can be traced back to poor installation and people not tightening wheel nuts correctly and to the right torque.

In most cases there is a big difference in torque between an alloy and a steel rim..... up to 50 foot pounds.

When we do wheels in the workshop we use a rattle gun to take them off and to put them back on we use a rattle gun with a torque tube that is ratted 20% less then the final torque setting...... the final stage is with the torque wrench and a white marker pen.

Some steel rims like the ones on our 200 series has a torque setting of just over 150 foot pounds, my wife struggles to do them up so for out on the road we use a 1/2 inch drive breaker bar that's 700mm long to get the leverage.

Back when we still lived down on the Diamantina River Road, had a phone call about 4.30am, to assist a bloke heading back to Winton. He had a mob of roos on board his GU ute, and had lost the rear passenger side wheel.

Found some old HJ45 studs & nuts in the store, and took them up to him. They fitted perfectly, and he was on his way in under an hour. The brake line had been damaged, so he blanked that off, and was in Winton(about 220 kms away) before the 'roos started to go "off".

Had a wheel come off a borrowd horse float once......never ever found the wheel.

Bob.

All Classic Range Rovers ,Discovery1 , and up to current Defender have 16MM 5 stud wheels with 6.5 inch PCD.
I have never ever seen a wheel come off any of these models or a stud break.

Except maybe mine when a specialist who shall remain nameless left the nuts hand tight. I was alerted by the clunking.

It appears that the Japs etc just under specify these things.
I haven't heard of a Range rover 38A D2 or D3 losing wheels or breaking studs either.
Maybe it's the difference between a dedicated 4WD manufacturer and one which makes 4WDs as well as all sorts of other cars.

Regards Philip A

Wheel studs are either Grade 8 (SAE) or Grade 10.9 (the metric equivalent of Grade 8 in SAE). Fasteners manufactured to Grade 8 or Grade 10.9 are made from low alloy medium carbon steel (commonly Nickel/Chrome/Molybdenum alloy), and they are heat treated to increase their strength and toughness.

Grade 8 and Grade 10.9 are classed as high grade fasteners, substantially stronger than regular "high tensile" Grade 5 (SAE) or Grade 8.8 (metric) - with the tensile strength of Grade 8/10.9 fasteners, up around 150,000 psi or 1034 Mpa.

When torqueing Grade 8/10.9 fasteners, the amount of torque applied is critical. The torque figures given, are usually for dry threads. If you lube the threads in any manner (anti-seize or oil or grease), then you need to reduce the torque figure by at least 10%.

A Grade 8/10.9 fastener is designed to be placed under tension that actually stretches the fastener a little, when proper torque is applied. This is known by engineers as "plastic deformation" - and the slight stretching of the fastener shank is what assists in keeping the tension on the item being retained.

If a Grade 8/10.9 bolt or stud is overtightened, this over-tightening seriously stretches the bolt/stud shank, until it can no longer apply tension under the plastic deformation principle. The shank actually becomes slightly thinner, if this happens.

You can pick this damage up by placing the jaws of a vernier caliper along the bolt /stud shank, in-line with the shank, and check to see if you can see daylight between the tops of any of the threads, and the vernier caliper jaws.
If you find that one or more threads isn't touching the caliper jaws, then the bolt/stud has been over-tensioned, and has been seriously damaged - and should be replaced immediately.

An over-tensioned Grade 8/10.9 fastener will invariably fail when an extreme load is applied. Quite often, if one wheel stud has been over-tensioned, all the studs on that wheel have been over-tensioned.

Alll wheels and hubs should be wire-brushed on the mating areas before re-installation. Dirt, rust and debris caught between the mating surfaces will crush when the wheel is in use, and this will release the tension on the wheel studs.

Hi Unners

It is incorrect (under or over) tensioning normally and using a torque wrench is way to go , and then re-checking a bit later.

I use both steel and factory alloys and factory alloys are more critical.

There is a little bit of wrong info above - the normal late model factory alloys use a chamferred nut which goes straight onto alloy surface of wheel.

This is unlike some aftermarket ones which use a flat surface and steel insert.

You can use the same wheel nuts for both factory alloy and steel wheels.

The amount of alloy thickness in the wheel nut hole is not as much as the steel wheel considering the different material strengths and it is simply easier to crush it.

Thanks everyone for all the comments. I don't think I'll ever really know what happenned although I now think that the two that sheared were most likely over tightened.

From now on whenever I have any work done I'll be getting my torque wrench out myself to check.