Copper grease - or not?

[witko999]

Pica-Pica said:

Equus said:

Never used it: just clean, dry threads.

Agree.
OP, ask yourself ‘do they use it in production?’.
The answer is a most definite no.
Should you use it in service?
The answer is a definite no.
Using grease and applying the same torque, will give an increased tension to the wheel bolt.

Mass production has many competing factors other than just doing 'what is best'. Cost being a very major one of them.

[Megaflow]

witko999 said:

Pica-Pica said:

Equus said:

Never used it: just clean, dry threads.

Agree.
OP, ask yourself ‘do they use it in production?’.
The answer is a most definite no.
Should you use it in service?
The answer is a definite no.
Using grease and applying the same torque, will give an increased tension to the wheel bolt.

Mass production has many competing factors other than just doing 'what is best'. Cost being a very major one of them.

Indeed. Also, during production, the OEM will have a strict standard for what coating and protection is on any critical fastener and then the torque will be set around that coating and surface protection.

What an OEM will *not* do, is torque any bolt that is 100% dry, because that is likely to lead an under torqued bolt due to binding.

[Matt_E_Mulsion]

I use a small amount on car wheel studs/bolts and I also put a smear between the face of the wheel and the hub to save the wheel getting stuck.

I started my career 25 years ago and that is what our mechanics did back then and I have done ever since, never had a problem.

[Mave]

steveo3002 said:

thebraketester said:

I always use aluminium anti sieze on my wheel bolts and mating faces.

and have they ever fell off?

id say someone keen enough to use something is also wise enough to tighten the wheel nuts properly

You can tighten the wheel nuts to the spec torque, but if you lubricate the joint faces then the joint isnt loaded in the way it was intended. Those mating surfaces are intended to take ~90% of the torque. If you lubricate them, the bolts end up taking the torque in bending instead. Personally I make sure the threads and joint surfaces are clean and take the wheels off twice a year for servicing.

[Ivan stewart]

Matt_E_Mulsion said:

I use a small amount on car wheel studs/bolts and I also put a smear between the face of the wheel and the hub to save the wheel getting stuck.

I started my career 25 years ago and that is what our mechanics did back then and I have done ever since, never had a problem.

This and if you want accurate torque you won’t get a consistent value if the threads aren’t perfectly clean with a drop of oil on them Oil is the safest especially in our damp and salty environment,
The thing that’s most likely to result in wheels coming lose is rust or corrosion on mating surfaces !!,
So scrape it off and use a smear of grease then do the nuts up evenly by hand if possible Not a rattle gun !!then a torque wrench or by feel .

[thebraketester]

Both bolts cleaner with brake cleaner and a wire brush.

One bolt dry and one bolt lathered with aluminium anti seize.

Bolt bolts threaded on and finger tightened with a socket.

Both marked TDC. Checked again for finger tightness repeatability.

Both torqued to 120nm.

Which one spun the greater angle?


/100% valid scientific experiment

[Mave]

thebraketester said:

Both bolts cleaner with brake cleaner and a wire brush.

One bolt dry and one bolt lathered with aluminium anti seize.

Bolt bolts threaded on and finger tightened with a socket.

Both marked TDC. Checked again for finger tightness repeatability.

Both torqued to 120nm.

Which one spun the greater angle?


/100% valid scientific experiment

I'm guessing the one with the anti seize but looking forward to the answer.

[Matt_E_Mulsion]

I'll go with hardly any noticeable difference.

[E-bmw]

The difference would be much more if the mating surfaces were greased than just the threads.

[Smint]

The non lubed thread is clean and corrosion free, because of that i too doubt there's much difference, but there would have been if the taper seats had been lubed.

[witko999]

Mave said:

steveo3002 said:

thebraketester said:

I always use aluminium anti sieze on my wheel bolts and mating faces.

and have they ever fell off?

id say someone keen enough to use something is also wise enough to tighten the wheel nuts properly

You can tighten the wheel nuts to the spec torque, but if you lubricate the joint faces then the joint isnt loaded in the way it was intended. Those mating surfaces are intended to take ~90% of the torque. If you lubricate them, the bolts end up taking the torque in bending instead. Personally I make sure the threads and joint surfaces are clean and take the wheels off twice a year for servicing.

How on Earth is lubing a thread and/or cone introducing a bending moment?

[Megaflow]

thebraketester said:

Both bolts cleaner with brake cleaner and a wire brush.

One bolt dry and one bolt lathered with aluminium anti seize.

Bolt bolts threaded on and finger tightened with a socket.

Both marked TDC. Checked again for finger tightness repeatability.

Both torqued to 120nm.

Which one spun the greater angle?


/100% valid scientific experiment

I’d be surprised if there was a noticeable difference.

[Megaflow]

Smint said:

The non lubed thread is clean and corrosion free, because of that i too doubt there's much difference, but there would have been if the taper seats had been lubed.

What? Who lubes the tapered seat?

I put a smear of copper grease on threads, nothing like as much as the photo above with the aluminium anti seize. But *never* on the taper! It is the taper that is doing the work.

[Hammer67]

Matt_E_Mulsion said:

I use a small amount on car wheel studs/bolts and I also put a smear between the face of the wheel and the hub to save the wheel getting stuck.

I started my career 25 years ago and that is what our mechanics did back then and I have done ever since, never had a problem.

^^^^^ This.

[brman]

kambites said:

RizzoTheRat said:

donkmeister said:

I'm one for a small amount of copper slip on the mating surfaces though, I have needed to whack wheels to unstick them in the past.

That's a whole other debate. Lots of people seem to do it with no problem, but the bolts provide the clamping force to get the friction on the mating surface between the hub and the wheel. Greasing that surface is in theory a bad idea.

In practice I think there's so much margin for error that it does no harm, but it does sound like a thoroughly daft idea!

Well, in practice, yes - it is a daft idea and I have proof! (well sort of...)
I have owned two cars where the wheels have come loose (to the extent of wobbling and making a horrible noise when driving). In both cases, when I investigated, there was copperslip on the mating surface of the wheel/hub (not done by me!). I cannot prove the copperslip caused the loose wheel but it is definitely the main suspect.
To be fair, in both cases there was significant copperslip still present on the mating surfaces. A thin smear, wiped off afterwards would possible be ok but, having experienced the consquences, I would never risk it. I would much rather a wheel stuck on (easily fixed with a bit of maintenance anyway) than fell off......

[thebraketester]

The result was that they both required a ~90 degree turn to get them to 120nm.

Not incredibly scientific I know, but that should go some way to dispel the over torquing argument.

[steveo3002]

meanwhile dozens of garages are gunning them on close to snapping and the customer is happy because they dont know any better

[CrutyRammers]

witko999 said:

Mave said:

steveo3002 said:

thebraketester said:

I always use aluminium anti sieze on my wheel bolts and mating faces.

and have they ever fell off?

id say someone keen enough to use something is also wise enough to tighten the wheel nuts properly

You can tighten the wheel nuts to the spec torque, but if you lubricate the joint faces then the joint isnt loaded in the way it was intended. Those mating surfaces are intended to take ~90% of the torque. If you lubricate them, the bolts end up taking the torque in bending instead. Personally I make sure the threads and joint surfaces are clean and take the wheels off twice a year for servicing.

How on Earth is lubing a thread and/or cone introducing a bending moment?

He's talking about the mating surfaces, is he not?
Less friction on those surfaces = they move in sheer = the bolts will take a bending force.

[thebraketester]

How much force is required to bend or shear four/five M14 bolts?

[Krikkit]

thebraketester said:

How much force is required to bend or shear four/five M14 bolts?

About 60kN each, i.e. 600kg.

The reason it doesn't matter that much what we do with wheel nuts and mounting faces (including way over-torquing them with a big impact at your local tyre fitter) is they're way, way over-specced to build in huge tolerance to abuse and fatigue.