Wheel nuts..

Jaahn · Guru

RE: Wheel nuts..

Eaglemax · Guru

erad wrote:
Manufacturers can use dry unlubricated threads for 2 reasons:
1 Their environment is clean and they are using new products, and
2 To use a lube on the threads could be messy and more expensive.

Tightening threads in the real world is a totally different matter. The only way you can get a reliable tension into a bolt is to physically measure the bolt extension (typically with a dial gauge). This then allows you to assess the actual tension in the shank of the bolt. That is impractical for all but critical bolt installations. The next best method is to use lubrication. Light machine oil is usually recommended although a thin smear of grease on wheel studs will do just about as well. Lubricating the threads reduces the variability of the friction component, and makes for a more reliable clamping. Tightening a dry thread the friction can vary enormously. Where manufacturers specify dry tightening, they have probably made allowances in the recommended torque that the tension in the bolt shank will not be excessive.

Interestingly, I have checked the workshop manual for my vehicles (both Mitsubishi) and they give a tightening torque but make no reference to lubricating the threads. Therefore I assume that they are talking about tightening the threads dry. The figures given were 110 Nm (81 ft-lb). Years ago I had a Triumph 2000 which the workshop manual specified torques for every bolt in the car. They said 60 ft-lbs for the wheel nuts, but lubricated threads. I tightened the bolts to this figure, and then went round and tightened them again by hand because to me this felt far too loose. However, the 60 ft lbs figure would probable give the same bolt tension as the 81 ft lbs of my Pajero, the Pajero having 6 bolts vs 4 of the Triumph.

Appreciated, much detail. Thanks

Tony

Eaglemax · Guru

-- Edited by Eaglemax on Monday 7th of June 2021 08:07:44 PM

Craig1 · Guru

Just had a look at my Toyota LC200 2017 manual. It says "do not use oil or grease". Also to recheck aluminium wheels at 1600km. No mention of torque values.

erad · Guru

Craig1: I am surprised that Toyota do not tell you what tension to use on the wheel lugs. but they do say to recheck the tension after 1500 km on aluminium wheels. This is because aluminium creeps under tension or compression, and when you put significant loading on the heel nuts, you are compressing the aluminium of the wheel hub as well. As this compresses, it is the same effect as the wheel nut loosening. After a few tightenings, things settle down and regular checks should not e required unless you disturb the wheel nuts eg changing wheels etc. Aluminium wheel nuts also often have a nylon washer between the face of the nut and the wheel hub. The nylon also tends to squish out a bit and re-tightening is required because of this. Sunrasia wheels also have a suggestion to re-tighten the wheel nuts after 1500 km, this time I suspect because the wheels are painted and the clamping surface is painted. after a while, the paint crumbles away, thereby leaving the wheel nuts loose.

If the wheel nuts are not tight enough, you can get regular load changes on the studs as you drive along. This cyclic loading can eventually cause fatigue in the bolt shank, normally right at the end of the thread cutting area. This is where there is some stress concentration due to the machining of the thread. If the initial bolt tension is enough to exceed the cyclic loading on the bolts, the studs will never feel the cyclic loading as the car drives along, and therefore the bolts will not be subjected to fatigue loading. The same theory apples to cylinder head bolts, or for that matter, any bolts which are subjected to cyclic loading - as long as the pre-load exceeds the in-service loads which are being applied to the bolts, they will not be subjected to the variable loads and the bolts will not fatigue in service. A few years ago, Nissan Patrols used to lose wheel quite often. I suspect that the wheel studs may have been too small in diameter, but people could also have been tightening the bolts too much, thereby taking the stud material to and beyond yield point. I haven't heard of any Patrols losing their wheels lately, so maybe they have cured the problem.

Craig1 · Guru

131nm for aluminium wheel, in another part of the 699 page manual. Also get it torque checked if changing a flat somewhere.

But no mention from dealer of checking at 1600km after a service which includes rotate,balance,wheel align. Perhaps their perfect torqued rattle guns dont need to be checked?

Whenarewethere · Guru

133Nm for my Land Rover.

Les Bishop · Member

I will probably get the same reaction I got on the oil thread , but here goes it doesnt matter weather a big caterpillar dozer or a kenworth primemovr or your four wheel drive all torque values are with lubrication unless other wise stated in the relevant workshop manual. Regards Les

Les Bishop · Member

I will probably get the same response I got in the lubricant thread . You can listen or not I dont care . It doesnt matter weather a large caterpillar dozer or a truck prime mover or your four wheel drive all torque values as stated are with lubrication un less stated in manufactures work shop manual . Regards Les

Gravy73 · Veteran Member

JackoFJR wrote:
https://www.youtube.com/watch?v=d7UDy7B0-m8

Well it comes down to, do you believe the fastener manufacturer or the fastener user? I think I prefer the first choice. For the sake of further controversy how many people apply grease to the mating surface of the wheel hub to prevent the wheel binding to the hub? This occurs reliably on my vehicle fitted with wheel bolts and not studs and nuts.

Aus-Kiwi · Guru

I have issues getting the bloody things undone !! Good luck getting some old rusted nuts off out in the bush !! I carry a torque multiplier now !! To tighten ? I go 30flb then 90* . The old TTY so all tightened the same ! 10 studs & nuts in my case !

Whenarewethere · Guru

Milwaukee 1 inch battery impact wrench. 2033Nm on, 2440Nm off. Should be no argument!

https://www.milwaukeetool.com.au/power-tools/impacts-and-fastening/impact-wrenches/M18ONEFHIWF1-0.html

Dicko1 · Senior Member

Gravy73 wrote:
JackoFJR wrote:
https://www.youtube.com/watch?v=d7UDy7B0-m8
Well it comes down to, do you believe the fastener manufacturer or the fastener user? I think I prefer the first choice. For the sake of further controversy how many people apply grease to the mating surface of the wheel hub to prevent the wheel binding to the hub? This occurs reliably on my vehicle fitted with wheel bolts and not studs and nuts.

I did it all the time on my trailer. Didnt need to on my car as the surfaces were flatter and wheels alloy. Trailer was steel to steel and not 100% flat. Coating of grease or anti seize saw the surfaces rust free and easy to take off.

bomurra · Veteran Member

I think we need to take some advice from the manufacturers of bolts, studs and nuts, they have undertaken all of the scientific research necessary on this topic.

Here in Australia we have a manufacturer Ajax Fasteners who produce an excellent Technical Reference Manual on all types of fasteners.

It is available from their website and covers in detail, tightening of all kinds of bolted joints, with all kinds of fasteners. It provides information on torque settings for fasteners with different surface conditions, including dry, and heavy greased fasteners including anti seize.

The manual has all of the scientific and engineering tech data you could ask for.

It states - "Because friction is the major unknown variable affecting the relationship between torque applied and tension induced, the presence of light oil lubrication is the minimum standard recommended for consistency in controlled tightening of fasteners. Most plain finish fasteners are supplied with sufficient oil residue from their processing plant, but plated finishes will generally require oiling, or adjustment to the torque recommended in the Ajax Fasteners' Technical Data. For bolts with surface finishes or assembled with anti-seize or heavily greased, the torque induced preload relationship is likely to be altered and the recommendations to require modification." Remember they are referring to initial tightening here.

It then has a table showing various fasteners (bolt/stud etc.) with differing surface finishes, with a factor that the recommended standard torque value should be adjusted by, for each. With "heavy greased" showing as 70% of the standard torque setting.

The Ajax Manual also states that "dry bolt" joints are subject to the greatest variation in clamping force, owing to variations in fastener friction. Dry fasteners (tightened to the same torque), can show a variation of up to 20% in clamping force, with repeated use, which with adequate lubrication" can be reduced to a variation of 10%.

So, they don't say not to use grease, they say if you lubricate fasteners with proper adjustment to your tightening torque setting, the clamping force you obtain will be more reliable and reproducible.

To repeat, lubricated fasteners will provide a more reliable and reproducible clamping force, but strict attention must to be paid to the tightening torque, so you don't exceed the design parameters of the fastener.

One wonders what happens at the tyre shop or dealership when you take your van/car for service with greased studs, and the rattle gun is used, at greater than the specified tightening torque.

Craig1 · Guru

And for a variation,
Most aluminium/alloy wheels have a nut with a sealed end, so how does that affect the whole thing, and would anyone check inside said nut for moisture, dirt, or lubricant?

iana · Guru

Well Aussie-Paul, you started this ! was the Jesus nut on your gyro-copter lubricated ?

oldbloke · Guru

JackoFJR wrote:
https://www.youtube.com/watch?v=d7UDy7B0-m8

Lol. He talks a lot.

Almost any oil or greas will do the job. But just a tad. Even diesel, being a light oil would help if you have nothing else.

Dicko1 · Senior Member

erad wrote:
JackoFJR's link is very good, Normally, this guy has the same effect on me as laxettes, and indeed it was the same this time, but everything he said is spot on. I thoroughly endorse what he has said about bolt tightening.

Same here. Of course some of the "gurus" on here will disagree but in my experience with many klm,s of remote area travel with 4 wd,s, 6wd trucks and trailers in all sorts of conditions has proven to me that sensible lubrication of the wheel studs has huge benefits when a problem arises with your wheels. Not only wheel studs but many other bolts on a vehicle as well. So much easier when changing flat tyres.

-- Edited by Dicko1 on Thursday 10th of June 2021 10:48:28 AM

Mike Harding · Guru

Interesting thread.

Being an electronics engineer I'll not venture an opinion but I do wonder about all the nuts and bolts which spend their entire life in an oil bath environment - big-end bolts come to mind - I imagine oil will, eventually, seep into their threads?

Mike196 · Senior Member

When he speaks about corrosion, it was interesting to see some corrosion on the lip of the hub where the wheel locates and a light coat of surface rust on the thread of the stud. This on a relatively new car, it's no wonder people have problems down the road once time has had an effect on the fastener joints.

KJB · Guru

Mike196 wrote:
When he speaks about corrosion, it was interesting to see some corrosion on the lip of the hub where the wheel locates and a light coat of surface rust on the thread of the stud. This on a relatively new car, it's no wonder people have problems down the road once time has had an effect on the fastener joints.

And that is where a smear of Coppercoat does its job ...and makes life easier "further down the track...."

Mike196 · Senior Member

Have just been out & checked mine, (Pajero) dry as! It's just been in for a wheel align check and first tyre rotation. Good thing my wheel brace is larger than the normal ones, the nuts on the spare wheel had been done up so tight the washers took the powdercoat off the alloy undoing them! Have done all the studs and torqued all to 90Nm. Will see what happens now.

-- Edited by Mike196 on Thursday 10th of June 2021 01:39:51 PM

erad · Guru

Mike Harding wrote "Being an electronics engineer I'll not venture an opinion but I do wonder about all the nuts and bolts which spend their entire life in an oil bath environment - big-end bolts come to mind - I imagine oil will, eventually, seep into their threads?"

Big end bolts are typically tightened to a pre-determined tension. For a start, they are usually well machined and normally are dry. They are tightened up to give a pre=load on the bolt which exceeds the tensile load of pulling the piston down. As long as the pre-load is greater than the applied tensile forces, the bolts will not suffer any fatigue loading and therefore will not fail that way, Older big-end bolts used to have tab washers on them to ensure that the nuts didn't come undone. But if the pre-load in the bolts was not enough to over the cyclic tensile loading, the bolts could still fail in fatigue.

Jaahn · Guru

Mike Harding wrote:
Interesting thread.
Being an electronics engineer I'll not venture an opinion but I do wonder about all the nuts and bolts which spend their entire life in an oil bath environment - big-end bolts come to mind - I imagine oil will, eventually, seep into their threads?

Hi smile

To get a bit technical and not applicable to wheel studs (for obvious reasons I hope ) the car manufacturers in particular but all industrial applications, now have developed tightening to yield, TTY, to be the most reliable form of tightening any fastener. It is almost immune to thread lubrication variation. Anyone who has done an engine recondition in the last decade(or two) will be surprised, annoyed, etc by the fact you usually need new studs bolts etc in critical places. Heads are a classical application hmm of TTY.

The theory is that the yield point of a steel is easily controlled at manufacture, very repeatable at near constant force(stress) as is the amount of the yield and behaviour. The manufacturer selects the wanted diameter for the necessary force required. So you tighten the fasteners up to a medium clamp force by torque to settle the joint, then the fasteners are turned a certain angle which will extend the shank by a set amount determined by the pitch. This can be done several times on head studs in order, till all the bolts are stretched into the yield region. This means all the fasteners have the same clamping force to a very close %. Much closer than torquing them under uncertain conditions of lube on the threads or faces. biggrin Indeed ideal for machine assembly, just count the turns.

Just for information the yield is very extensive on the steel used and the bolts can be reused at least once (and probably several times). I have reused head bolts on some engines working O/S with no problems. Usually an inspection and a measurement is specified, but the trade here does not agree and insist on new ones, which are now easier and cheaper to get. aww

Jaahn

-- Edited by Jaahn on Thursday 10th of June 2021 06:15:47 PM

Aus-Kiwi · Guru

Big end bolts when done PROPERLY is done by stretch . Head studs manufacturers like ARP SUPPLY lube so ALL bolts or studs are tightened the same !! Now days mainly using torque to yield method !

swamp · Senior Member

HI
Different applications require different thought .
Not all car makers have the same attitude towards lubed wheel nuts .
Makers that donot recommend lube adjust the tensions the same is tru for those that recommend lube .
Take driving miss daisey ,probably never need lube regular yearly service .
TAke miss daisey that never has wheels removed 1x every 5 years ,this needs lube .
Take offroad bob that drowns his 4x4 every weekend lube required .
Take old school mags that bind on nuts .lube needed .

Take poor quality nuts and studs that bind on threads from stretching ,lube slows the process.

Some makers use dry lube in factory.

Yup engineers design, mechanics maintain and regularly fix engineering flaws

Aus-Kiwi · Guru

Then some bright engineer fits left hand threads !! Dont get me started !!

Whenarewethere · Guru

My dad in amongst his too many tools had a pile of rusty left hand drill bits.

He said "thousands" of years ago changing speed in drill presses was done in both directions, for half the speeds each direction. So you had a set of right & left hand brill bits.

So every step up in speed you would have to swap the drill bit.

Aus-Kiwi · Guru

Yea left handed screwdriver too !

Jaahn · Guru

Aus-Kiwi wrote:
Then some bright engineer fits left hand threads !! Don't get me started !!

Well smile

It was found very early in automotive history that left hand threads on the left hand side and right hand threads on the right hand side resulted in more secure wheel nuts and axle nuts etc. This is because the tendency to undo is countered by the relative rotation. That is a well known fact and most heavy vehicles use that system. It was not imposed by a rogue engineer on the drawing board. hmm

As for the machine with every second gear being reversed. I have had to repair a high force testing machine 100T that was equipped with one of those bl**dy gearboxes. After the second disaster when an operator got it wrong and destroyed something by switching the motor the wrong direction, I made a mechanical lockout plate so the correct motor rotation could only be selected if in the right gear. How stupid was that design ! furious

Jaahn