# Wheel Nut Torque? Poll Added.



## mav696 (May 21, 2006)

*Do you grease your wheel nut?*​
Yes2240.74%No3259.26%


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## mav696 (May 21, 2006)

Any idea what I need to torque the wheel nuts to as I have just bought a new set of wheels and want them on the car staight away?
Cheers Mav.


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## barton TT (Nov 13, 2004)

Think it 120 Nm if i remember right. :?


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## TThriller (Feb 27, 2006)

barton TT said:


> Think it 120 nb if i remember right. :?


120Nm is correct. This is the only piece of important everyday info that is NOT on Wak's Wide Web :lol: :lol:

TThriller


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## R6B TT (Feb 25, 2003)

TThriller said:


> barton TT said:
> 
> 
> > Think it 120 nb if i remember right. :?
> ...


120nm is correct but 80nm for the locknuts


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## rob40 (Sep 3, 2004)

and i always tighten till the bar starts going white  
yep 120Nm is correct


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## John-H (Jul 13, 2005)

R6B TT said:


> TThriller said:
> 
> 
> > barton TT said:
> ...


I wouldn't make the locking bolts any less tight - they're all supposed to be the same. I know one person who has three different sets of locking wheel bolts fitted - that would be three bolts out of five loose! If he did that he might not get them stolen but they may fall off :lol:

Some copperslip on the threads will allow the torque wrench to work accurately and stop the bolts seizing with corrosion. If you don't lubricate the threads the torque wrench will go click at a much lower torque (well actually same torque but you'll end up with much lower bolt tensile force).


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## Wak (May 6, 2002)

R6B TT said:


> 120nm is correct but 80nm for the locknuts


This only comes from the fact its very difficult to find decent locknuts.

They are either very secure but fragile and will chew themselves to bits or they are air gun strong but have a lesser level of protection.

I would still stick to 120nm all round. :?


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## garvin (May 7, 2002)

John-H said:


> Some copperslip on the threads will allow the torque wrench to work accurately and stop the bolts seizing with corrosion. If you don't lubricate the threads the torque wrench will go click at a much lower torque (well actually same torque but you'll end up with much lower bolt tensile force).


Incorrect. Wheel bolt torques are quoted for dry threads. Grease them in any way and they will be overtightened and overstretching the bolt threads. Just make sure the threads are cleaned up by a good wire brushing.


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## TThriller (Feb 27, 2006)

garvin said:


> John-H said:
> 
> 
> > Some copperslip on the threads will allow the torque wrench to work accurately and stop the bolts seizing with corrosion. If you don't lubricate the threads the torque wrench will go click at a much lower torque (well actually same torque but you'll end up with much lower bolt tensile force).
> ...


I agree all the way with John-H on this one. Dry threads are far, far too big a variable and therefore too unreliable for giving the correct torque. They are also so prone to seizing. I ALWAYS grease my threads with copperslip and torque to the quoted values: thats an upper-bound value anyway.

TThriller


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## UK225 (May 12, 2002)

I personaly do not lubricate my wheel bolts in any way, however this mainly because the wheels are regulary taken on & off so bolts seizing is not an issue & I always wire brush the threads to clean them up & I feel happy the required torque values are met accurately.

But I have thought at times about the arguments of to lubricate or not.

I am happy to be corrected but my thoughts would be..

If a bolt did not have a head, so if you like was a stud it would continually turn through a threaded hole until

A. It fell out the other side

B. It hit an obstruction ie not a through hole

If you continued to turn it after hitting an obstruction, force through compression would be generated on both the end of the bolt (small surface area) & the threads through which it was turning ( larger surface area in the case of a wheel bolt hole ) so it would it would seem to me the highest point of force exerted over area is at the end of the bolt as it has a smaller surface area than the threads.

So with that in mind,
.
In the case of a wheel bolt it will turn until the face/head meets the seat of the hole in the wheel, the force generated on the bolt ( this time through tension) required to reach a specific torque level is met surely through the face/head turning against the seat, with force transferred to the threads through this action.

If anything I cant see putting copper slip on the threads being an issue, surely issues could only arise if the mating face of the bolt was lubricated.


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## UK225 (May 12, 2002)

Forgot never torque your locking wheel nuts to a lower value than 120 Nm, as has been already been said by others.

To carry out this practice would not be advisable.

If something is not up to being subjected to how it should be correctly used get something that is.


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## garvin (May 7, 2002)

TThriller said:


> garvin said:
> 
> 
> > John-H said:
> ...


Of course, you can do what you like. However, bear in mind that the grease that makes them easier to do up also makes them easier to come undone. The torque level specified depends on the bolt and hub material and the level is designed such that the bolt locks in position without passing the plastic deformation limit of the bolt threads. Continual over-torquing will eventually fatigue the bolt threads and if they begin to collapse the bolt will actually loosen .......... and then vibrate undone on a nice bed of grease which has reduced the friction. As I say, you can do what you like but when it comes to keeping the wheels on I would rather do it correctly.


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## TThriller (Feb 27, 2006)

If you want unreliable tension in your bolts, due the wide variabilty in the degree of resistive friction in a dry bolt, caused a bolt and hole that has a variable degree of corrosion in them, and want to suffer the resulting fatigue due to the bolt being only partially preloaded and therefore subject to cyclic loading, then go ahead: dont grease the threads.

If you want consistantly applied full preload tension in the bolts, grease them and ALWAYS tighten them with a torque-wrench.

You will ONLY over tension the bolt if you dont use a torque-wrench or you air-gun the bolts.


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## garvin (May 7, 2002)

TThriller said:


> If you want unreliable tension in your bolts, due the wide variabilty in the degree of resistive friction in a dry bolt, caused a bolt and hole that has a variable degree of corrosion in them, and want to suffer the resulting fatigue due to the bolt being only partially preloaded and therefore subject to cyclic loading, then go ahead: dont grease the threads.
> 
> If you want consistantly applied full preload tension in the bolts, grease them and ALWAYS tighten them with a torque-wrench.
> 
> You will ONLY over tension the bolt if you dont use a torque-wrench or you air-gun the bolts.


As long as the threads are cleaned up (such that the bolt can easily be done up hand tight - i.e. there are no significant obstructions on either thread) there will be no 'unreliable' tension - it will be a lot closer to the design 'pre-load' than greasing will provide for. As for 'cyclic loading' due to partial pre-load - that's a new one on me, how does that work then? As for a using torque wrench I totally agree.


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## TThriller (Feb 27, 2006)

garvin said:


> . As for 'cyclic loading' due to partial pre-load - that's a new one on me, how does that work then? As for a using torque wrench I totally agree.


The following applies equally to cylinder head bolts, wheel bolts, or to HSFG bolts holding steel framed structures and bridges together.

When a bolt is fully pre-loaded the mating surfaces of the connected components will always experience a contact pressure. As the applied force between the components is varied, the contact pressure will change, but the clever thing is this: if the service value of applied tension is less than the bolt pre-load tension, the *bolt force* will remain *constant*. Hence the stress in the bolt will be constant and not suffer from fatigue caused by cyclic stress changes.

But... if the bolt is only partially pre-loaded and the force applied to the connected components exceeds the bolt pre-load, then the bolts will be subjected to the excess force over and above the pre-load force. The increase in force changes the stress in the bolts subjecting them to the cyclic stress changes, and thus the potential onset of fatigue. Once the pre-load force is exceeded and the bolts are taking greater load they will extend, allowing the joint in the connection to open up and then to close as the force reduces. It is this change in extension or strain in the bolt that can cause premature failure of the bolts. It is also the mechanism which causes bolts to loosen...

In the case of the cylinder head bolts, the idea of bolt pre-load is to ensure that whatever forces the explosions in the cylinders creates; the joint between the head and the cylinder block will not open up. In this situation (and the structural bolts situation), the bolts are tensioned beyond their elastic limit and will usually need replacing if the components are disassembled.

I do hope that Iâ€™ve written this well enough for you to understand what Iâ€™m trying to put over.

But you might like to look at this for further reading:

http://www.tech.plymouth.ac.uk/sme/desn ... sbolta.htm

TThriller


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## Speed Racer (May 21, 2006)

garvin said:


> TThriller said:
> 
> 
> > garvin said:
> ...


No worries Garvin...you're correct. You NEVER grease wheel bolts! You'll overtighen for sure and it wouldn't take much in the way of stress to break them all loose.


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## John-H (Jul 13, 2005)

This is taken from the Bentley manual. The bolts are meant to be greased:










Castrol Optimol TA Datasheet

The TA is just an antiseize lubricant. You should be fine with Copperslip.

The wheel bolts used are not stretch bolts like cylinder head bolts, so at the specified torque there is no way the wheel bolts are going to be taken into their plastic deformation yeald point i.e. they are just going to be stretched elastically and will return to their original length greased or not.

It's important, however, to have a consistant and minimal friction coefficient to minimise the error of the torqueing process. Significant errors caused by excess friction will reduce the tensile force in the wheel bolt below what it is designed to carry, resulting in lower wheel clamping forces. This becomes even more significant where wheel spacers are used where the longer bolt assembly is more prone to thermal cycling effects and interface irregularitiy and settling.

Bear in mind, however, that if you don't apply antiseize you could be overstressing wheel bolts when you take them off! A very seized bolt could require a torque way higher than the 120Nm used to tighten them in order to shift it. This may also explain broken locking wheel nuts. Who uses a torque wrench to undo bolts? Try it next time on dry corroded threads and see if the torque wrench is even capable of reaching the required torque.


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## TThriller (Feb 27, 2006)

Speed Racer said:


> No worries Garvin...you're correct. You NEVER grease wheel bolts! You'll overtighen for sure and it wouldn't take much in the way of stress to break them all loose.


What a load of nonsence!!!

Get your facts right before posting misleading info!!!

TThriller


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## TThriller (Feb 27, 2006)

John-H said:


> This is taken from the Bentley manual. The bolts are meant to be greased:
> 
> 
> 
> ...


Absolutely right John! And you have backed up you info with published facts - nice one.

TThriller


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## Wak (May 6, 2002)

The bentley pic is misleading , whats the difference in surface 2 & 5 ?

One says grease, other says do not grease yet both are the surface making contact with the wheel.


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## Speed Racer (May 21, 2006)

TThriller said:


> John-H said:
> 
> 
> > This is taken from the Bentley manual. The bolts are meant to be greased:
> ...


This is like a game where the opponent constantly changes the rules during play :wink: ...here the new rule is the addition of a new variable...the process to re-use corroded bolts. WTFO? Anyway, I'll continue to play it safe with dry threads, even though I believe that the use of "lightly" applied anti-seize wouldn't have the adverse affect that normally one envisions when on the subject of greasing wheel bolt threads. Humans have a trendency to overdo things, like tightening bolts and applying grease. The combo ain't good either. :!: I'm willing to bet that not everyone in this audience has your experience,or even has a torque wrench for that matter. My attempt was to play it safe for the masses, not the experienced.

Cheers!


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## Speed Racer (May 21, 2006)

TThriller said:


> Speed Racer said:
> 
> 
> > No worries Garvin...you're correct. You NEVER grease wheel bolts! You'll overtighen for sure and it wouldn't take much in the way of stress to break them all loose.
> ...


Get your argument correct first...


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## Rhod_TT (May 7, 2002)

Wak said:


> The bentley pic is misleading , whats the difference in surface 2 & 5 ?
> 
> One says grease, other says do not grease yet both are the surface making contact with the wheel.


I think it is because to allow the bolt to rotate in the second picture it's actually the interface between the head and the tapered washer that needs lubing and not the tapered washer itself.

But isn't the torque all to do with creating tension in the bolts and nothing to do with the resistive torque of the thread directly. Hence I don't think it matters whether you lube them or not before you put them on. The tension in each bolt is determined by axial load (which is created by the wedge from the screw thread). I think I might be digging a hole here!!!

Anyone have their wheels fall off either with lubing or not lubing threads? Personally, I've never had a problem with wheel bolts coming loose when they're lubed or not so long as I torque them to the correct value.


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## John-H (Jul 13, 2005)

Rhod_TT said:


> Wak said:
> 
> 
> > The bentley pic is misleading , whats the difference in surface 2 & 5 ?
> ...


You're right about the surfaces 2+5 - the bolt B has surfaces 6+3 lubricated so simply doesn't need surface 5 lubricating but it wouldn't do any harm if you did.

The "wedge" from the screw thread is a form of leverage where rotational torque T (120Nm), is converted into longitudinal tensile force F, by the force tangential to the bolt thread (Torque T (Nm)/(bolt radius r (m)), divided by Tan(thread angle - pitch to bolt circumference) approximately. But there's a friction term...

*F = T / [r . tan ( λ + φ )]* , or rearranged, *T = F . r . tan ( λ + φ )*

T = Torque (Nm)
F = Tensile force (N)
r = bolt radius (m)
λ = Thread angle, ArcSin(Pitch/bolt circumference) (degrees)
φ = Friction angle arctan(μ) where μ is the coefficient of friction.

This is only a simplification as it depends on thread form etc but from this you can work out for example, that a cylinder head clamping force is around 500 tonnes!

The TT wheel bolts are M14x1.5 (I think) so, 120Nm would create a maximum of 50 tonnes tensile force per bolt - unless my maths is up the spout after a beer or two :roll: .

The point is though, that φ generates an error and if the friction rises too much it could easily halve the tensile force in the bolt or more. It's best to make the φ error small by lubrication.

There was a case of someone on this forum, with wheel spacers, having their wheel come off after having a wheel replaced at Awesome. Allegedly a torque wrench was used - I wonder if the threads were corroded though?

For further info:
Good reference

More in depth analysis:
See P 13-7


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## gt russell (Nov 27, 2005)

yes john that was sim, his wheel came off


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## garvin (May 7, 2002)

Whoa, leave the forum for a day or so after posting and look what happens. Let's deal with a couple of the issues:-

Corroded bolts - never use them - period. If they have light surface deposits then clean threads with wire brush and run bolt in and out of bolt hole in hub to clean up so that they can be easily be 'done up' hand tight. I think this is the advice I have maintained throughout this thread. In this way there is no need for grease at all. If such threads are greased then the bolt torque needs to be adjusted - with the unknown properties of the grease (or oil if used) and no adjustment of the torque then it *WILL* be incorrect.

Greasing - don't do it, it is wrong - period. However, there are specialist pastes on the market which are specifically designed for thread applications with characteristics such that the torque level applied does not have to be altered. They are not just lubricants but are also anti-seize compounds that have good prperties under high load and temperature. Castrol Optimol TA paste is one such specialist compound with very sophisticated properties designed for such applications and can be used .............. but I think the 'thrust' of this thread is not about such specialist compounds but about the use of 'common or garden' grease which is designed, primarily, for lubrication and for which the characteristics are just not known or too variable from one 'grease' to another when used in such applications.

I rest my case m'lud :wink:


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## John-H (Jul 13, 2005)

*Steel on steel coefficient of friction = ~0.74
Castrol Optimol Paste TA Coefficient of friction = 0.12*

The fact is that the TT wheel bolts are specified to be torqued when greased with Optimol TA paste - not dry!

The two coefficients of friction quoted above clearly show there is a difference. If you torque the bolts dry they will not have enough tensile clamping force due to the friction causing the torque wrench to go click too early - see the equation I posted earlier - you may be down to 20% of the required preload.

Comma Copaslip is an antiseize compound specified for use with wheel bolts and spark plugs - it says so on the tin. I have not been able to find a reference to it's coefficient of friction but I would think it is close to the Optimol TA antiseize.

We are not talking about oiling the threads which would reduce the coefficient of friction to around 0.025. This may allow the bolts to undo themselves as it's the friction that keeps them in place.

The bottom line is to follow the manufacturers recommendation - if they specify a torque with dry bolts then stick to that reigime - if they specify lubrication then follow the recommendation. Luckily the TT is specified with lubrication which gives more consistent torque and allows the easy prevention of corrosion.

http://www.carbidedepot.com/formulas-fr ... icient.htm


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## Wak (May 6, 2002)

John-H said:


> Rhod_TT said:
> 
> 
> > Wak said:
> ...


*This is only a simplification* :lol: :lol: :lol:

I'll go get me coppa slip!


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## TTCool (Feb 7, 2005)

And I'll go and get me coat.


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## John-H (Jul 13, 2005)

:roll: :wink:


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## garvin (May 7, 2002)

John-H said:


> The fact is that the TT wheel bolts are specified to be torqued when greased with Optimol TA paste - not dry!


Are you sure that is 'a fact'. Handbook says to make sure the wheel bolts are "clean and turn easily". The Bentley manual appears to suggest that Optimol TA be used when wheel bolts are "slightly corroded" (although it can be taken as being ambiguous).


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## Speed Racer (May 21, 2006)

When in doubt...ask a German. I was down at my local BBS wheel shop on Monday and I asked what their opinion was on the subject of wheel bolts, lubed, what have you. Mind you I have BBS bolts, not Audi, but their opinon was that you shouldn't use corroded bolts, and dry is preferred, but an anti-seize paste thinly applied is OK too. So devoid of the need for technical explanations, I'll try my best to use non-corroded dry bolts with a super thin layer of anti-seize paste. All others are free to do as they wish.

Is there a GB on theapy sessions? I think I need help... :? Life's too short to screw yourself in the ceiling over this kind of chat. Forums should be fun, not contentious, and certainly not an avenue to go on the attack.

Hope everyone has a great day!

Cheers!


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## Speed Racer (May 21, 2006)

When in doubt...ask a German. I was down at my local BBS wheel shop on Monday and I asked what their opinion was on the subject of wheel bolts, lubed, what have you. Mind you I have BBS bolts, not Audi, but their opinon was that you shouldn't use corroded bolts, and dry is preferred, but an anti-seize paste thinly applied is OK too. So devoid of the need for technical explanations, I'll try my best to use non-corroded dry bolts with a super thin layer of anti-seize paste. All others are free to do as they wish.

Is there a GB on theapy sessions? I think I need help... :? Life's too short to screw yourself in the ceiling over this kind of chat. Forums should be fun, not contentious, and certainly not an avenue to go on the attack.

Hope everyone has a great day!

Cheers!


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## TTCool (Feb 7, 2005)

For what it's worth, I always clean my wheel bolts with a soft wire brush till they thread in by hand, and then progressively torque them diagonally to 90 lbs ft. No copaslip :roll:

Yes, I know that's a tiny bit more than 120nm.

Joe 8)


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## WozzaTT (Jan 15, 2006)

I haven't got a bloody clue either way.

HTH.


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## TTCool (Feb 7, 2005)

Wozzat?


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## John-H (Jul 13, 2005)

garvin said:


> John-H said:
> 
> 
> > The fact is that the TT wheel bolts are specified to be torqued when greased with Optimol TA paste - not dry!
> ...


I re-read the manual and I agree the wording could be less ambiguous but even if it did mean only to apply the antiseize on a corroded bolt, given that "corroded" could mean as little as a slight discolouration you could end up with perfectly good bolts that are then greased with the TA - so we're not compensating for a rough thread if you see what I mean.

Given also that the TA will reduce the coefficient of friction from ~0.74 to 0.12 and increase the preload by something like a factor of five (if my maths is correct), for the given torque, then surely they must intend the non corroded bolts to be treated also for consistency?

I certainly agree that common grease should not be used if only because it will melt and run, unlike TA and Coppaslip which withstand 1150Â°C.


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## garvin (May 7, 2002)

Speed Racer said:


> Life's too short to screw yourself in the ceiling over this kind of chat. Forums should be fun, not contentious, and certainly not an avenue to go on the attack.


Hey, some us enjoy a good ruck :wink: Of course forums should be fun but they are, this one especially, good places to learn ................. and that usually happens when a topic like this is 'done to death' by exchange of views etc. From my perspective these sort of issues are rather important and I'm glad they're not 'glossed over'. I'm sure we can all :-* and make up


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## mav696 (May 21, 2006)

God I didn't think asking this question was going to cause so many issues.
Sorry folks.
Mav


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## John-H (Jul 13, 2005)

garvin said:


> Speed Racer said:
> 
> 
> > Life's too short to screw yourself in the ceiling over this kind of chat. Forums should be fun, not contentious, and certainly not an avenue to go on the attack.
> ...


Totally agree  Some things you never quite get to the bottom of either. In looking for info on this one I notice it's been an ongoing hot topic on other forums too :wink:


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## TThriller (Feb 27, 2006)

mav696 said:


> God I didn't think asking this question was going to cause so many issues.
> Sorry folks.
> Mav


Don't be: this is an important issue well worth airing.

So what's the Forum consensous?

Perhaps *mav696*, as the thread owner, you could add a Poll?

TThriller


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## Rhod_TT (May 7, 2002)

I agree. Excellent thread. But do we have an answer?


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## John-H (Jul 13, 2005)

Well, the Bentley manual specifies the use of antiseize compound and presumably they have specified it on good authority from Audi.

Perhaps someone who has access to ErWin (official Audi corporate manual) could reveal what they specify. Here's a link to the homepage: ErWin

Only you have to pay


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## Wak (May 6, 2002)

*ElsaWin has the same picture and this text....*

Instructions for changing/fitting wheels
Important
Firm seating of wheel bolts and wheels is only guaranteed if the checks/instructions below are followed.
Check the following points when wheel rims are removed:

‒ Check that the seats for the wheel bolt heads in the rims and the contact surfaces between brake discs and wheel rims and between brake discs and wheel hubs are free of corrosion and dirt.
Remove oil, grease and corrosion as necessary and apply wax spray D 322 000 A2 for protection against corrosion. 
‒ Check that the centring hole of the wheel (rim) and the centring flange of the hub are free of corrosion and dirt.
Remove oil, grease and corrosion as necessary and apply wax spray D 322 000 A2 for protection against corrosion. 
‒ Check that the wheel bolts and the threads in the wheel hubs are clean. When fitting the wheels, the wheel bolts should screw in easily over the full length of the threads. 
‒ Clean dirty wheel bolts with a wire brush or similar.
Replace wheel bolts if they are badly corroded and/or damaged. 
*‒ If lightly corroded wheel bolts are re-installed on the vehicle, clean the threads and the area round the contact surfaces of the bolt head and grease the surfaces in sliding contact using Optimol TA paste, Part No. G 052 109 A2 as follows: *

→ A - One-piece wheel bolt: 
‒ Lightly grease the threads -1- and the cup-shaped contact surface -2-. 
B - Two-piece wheel bolt: 
‒ Lightly grease the threads -4-, and the area between the bolt head contact surface -3- and the back of the cup-shaped washer -6-. 
‒ Do not apply grease to the cup-shaped surface -5- that makes contact with the wheel rim. 
Note:
*
Use only Optimol TA paste, Part No. G 052 109 A2. The paste must not come into contact with parts of the brake system.*

‒ Make sure that the hole in the brake disc is aligned with the thread in the hub. The threads of the wheel bolts must not contact the hole in the brake disc. 
Installing wheels

‒ Secure all wheels as follows: 
‒ Screw in all wheel bolts uniformly by hand. 
*‒ While vehicle is still raised, tighten wheel bolts in diagonal sequence: 
‒ Tightening torque 50 Nm 
‒ Lower vehicle to floor and tighten all wheel bolts in diagonal sequence: 
‒ Tightening torque 120 Nm *


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## John-H (Jul 13, 2005)

Looks like they got their information from the same source Wak.


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## mav696 (May 21, 2006)

TThriller said:


> mav696 said:
> 
> 
> > God I didn't think asking this question was going to cause so many issues.
> ...


What would you like me to ask on the poll?


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## TThriller (Feb 27, 2006)

mav696 said:


> TThriller said:
> 
> 
> > mav696 said:
> ...


Do you grease wheel bolt threads - yes?

Do you grease wheel bolt threads - No?

Sorry, although a closely related issue to your original query regarding bolt torque, the thread has got a little diverted to the bolts greasing issue :wink:


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## Guy (May 13, 2002)

A different perspective......

When you are on the side of the road and it's hissing down with rain, (you need to get the girl next to you back to a place where you can correctly attend to her) and your wheel needs changing - do you want to get the bl**dy wheel nuts off or not?

Do you want to be the tart who calls the breakdown crew and 2hrs later you can drive off but - things have cooled down in the car or do you want to be the pit crew who can do the job quickly, without fuss and 20 mins later she is quietly impressed?

Do you want your wheel nuts and rims to corrode together and form this pitting and oxidising or not?

If you are changing your wheels every couple of months or (couple of hours on the track) then everything will be clean and useable because of frequent use.

Do you have gloves and a dusbin sized bag for the old wheel in the wheel well as well as everything else?


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## garvin (May 7, 2002)

Guy said:


> A different perspective......
> 
> When you are on the side of the road and it's hissing down with rain, (you need to get the girl next to you back to a place where you can correctly attend to her) and your wheel needs changing - do you want to get the bl**dy wheel nuts off or not?


I have a V6 - it has no spare wheel so, no, I don't need to get the wheel nuts off under these conditions .................. I need to connect up some crappy compressor and try to squirt some sort of gunge and pressure into the tyre to try and seal it.



> Do you want to be the tart who calls the breakdown crew and 2hrs later you can drive off but - things have cooled down in the car or do you want to be the pit crew who can do the job quickly, without fuss and 20 mins later she is quietly impressed


After failing to seal the punctured tyre as above, I'm afraid I will be that 'tart' who has to call for help



> Do you want your wheel nuts and rims to corrode together and form this pitting and oxidising or not?


No, but the painted rim usually stops this happening and it is unusual, but not impossible, for the wheel nuts to seize but usually in the threads not between bolt and wheel. The real issue is the back of the wheel sticking to the hub - by all means use a high melting point grease, Coppaslip or similar on the mating surfaces to stop this happening.



> If you are changing your wheels every couple of months or (couple of hours on the track) then everything will be clean and useable because of frequent use.
> 
> Do you have gloves and a dusbin sized bag for the old wheel in the wheel well as well as everything else?


Yes - always carry several pairs of 'surgical' type gloves and bin liners. The latter are usually to put my offspring's mucky sports wear in though, not the wheel :wink:


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## mav696 (May 21, 2006)

Poll added.


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## mav696 (May 21, 2006)

Only 3 votes, come on now folks.


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## TThriller (Feb 27, 2006)

mav696 said:


> Only 3 votes, come on now folks.


9 votes now

5 yes

4 no

Suprising


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## mav696 (May 21, 2006)

Come on now, only 12 votes and its neck and neck.


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## TTCool (Feb 7, 2005)

NO - Joe


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## John-H (Jul 13, 2005)

Here's an argument:

1/ The coefficient of friction (Âµ) of good rubber tyres on dry ashphalt is around 1.5 or even higher.

2/ Flinging your TT into a bend whilst braking can put most of the weight of the car on the outside front wheel (as the inside opposite lifts off).

3/ The distance from the road to the lowest part of the hub is about 10" and a further 4" to the outer PCD of the bolts. This forms a lever, with the wheel trying to prize out the bolts, with the bottom of the hub the fulcrum point. It's difficult to say where the bolts are as the wheel goes round but let's say they are an average of 2" from the fulcrum point. That gives a average force multiplication ratio of 10:2 = 5 and there are five bolts. On average therefore the bolt preload needs to be *1.5(Âµ) x 1 Tonne (~weight of car) x 5 / 5 = 1.5 Tonnes*, to correspond with the bend in this situation and keep the wheel clamped tight.










4/ In reality however, the tensile forces in the bolts cycle up and down as the wheel rotates and the upper bolts take all the strain (as that's where most lever movement occurs) with the lower ones taking little strain as they are by the fulcrum point with little potential movement. Perhaps the force multiplication ratio should be 10:4 = 2.5 and applied to one or at most two bolts at the top. This would put the required peak preload at nearer *1.5(Âµ) x 1 Tonne x 2.5 / 1 = 3.75 Tonnes (or 1.875 Tonnes if two bolts)*

5/ Now you always want your bolts to have a higher tension than the force the wheel is trying to prise them out with, otherwise relative movement will occur and your bolts will work loose. You also want a margin of safety to cope with shock loading.

6/ If you've followed this so far here's the clincher I think. From the equation I posted earlier in this thread, I've plotted a graph of bolt preload versus the friction coefficient of the bolt. Have a look at the graph and see where you'd like your bolt preload to be :wink:










The oiled threads give a preload way higher than needed but the antiseize gives a good and consistent margin. Dry threads are unpredictable and could promote movement due to inadequate preload.

The maximum possible preload corresponds with zero friction and is ~50 Tonnes. This cannot be acheved in practice as the bolts would simply unwind with no friction. In fact, with oiled threads, the friction angle (see equation) is close to the thread angle and therefore on the limit of working itself loose (well actually not because of "stiction"). With antiseize the friction angle is 3.5 times the thread angle so there is no danger of the bolts undoing themselves. With antiseize there is also no danger of movement because the preload is much higher than the dynamic load.

OK, I've made some approximations here and there is some argument as to what the Âµ of a dry bolt is but I don't need to tell you where I've cast my vote :lol:


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## thebears (Jan 14, 2006)

Back to school for me!


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## mav696 (May 21, 2006)

thebears said:


> Back to school for me!


I think I had better join you :lol:


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## TThriller (Feb 27, 2006)

John-H said:


> Here's an argument:
> 
> 1/ The coefficient of friction (Âµ) of good rubber tyres on dry ashphalt is around 1.5 or even higher.
> 
> ...


John, your a star! A great attempt to get some Math into the debate and qualify what you are saying. There are a few assumptions that should be quieried further. Refering to your points:

1) Agreed. But another way a looking at the lateral forces on the wheels is to consider the g-force that the car can generate. 1.5 g should be easily acheieved: could do with a bit more research.

2) Agreed.

3) Not quite right, more applicable to bolts without preload. As the bolts are all torqued up equally, the centroid of the clamping force is will be the centre of the bolts group, ie, the centre of the wheel. The fulrum will be the edge of the hub. Assuming a 6" hub as I've not got my wheels off, the lever arms are 9"and 3" so a ratio of 3.0, rather that 5.0. But this only illustrates another reason to pre-load the bolts correctly.

4) This is where I do disagree with you. As I tried to explain earlier, the tensile force in a *correctly pre-loaded* bolts does not cycle up and down: it remains constant. The stress only cycles when the pre_load is exceeded. Hence the need to achieve the specified torque in the bolt to achieve the specified pre-load tension. The change in applied force only changes the contact stress across the joint in the connected parts. The forces you have applied John are all SLS, we should be looking at factored ULS forces. A factor of 1.5 should be about right. Which sort of gets us back to your forces.

5) Agreed

6) The equation I think you are refering to is "Given also that the TA will reduce the coefficient of friction from ~0.74 to 0.12 and increase the preload by something like a factor of five...". It has a componant missing: the friction under the bolt head seating. See if you agree John and try to build that into the equation to make it more realistic.

But generally John, a very good attempt to justify your (our) argument.

Pity you didnt post this before the Poll 

So, to all you un-believers out there, if you want your wheels to stay on: *grease the threads*! It's the *only way* you will ever achieve the pre-load in the bolts that the manufacturer has specified.

Oh and to avoid any ambiguity, we are not talking about "common or garden" axle type grease. By grease we mean Optima TA or other high temperature anti seize compound.

Remember this: the dry thread idea is related to NEW BOLTS *AND* NEW HUBS. And what do you get on new threads?!? MACHINE OIL! Even if you fit new bolts or fastidiously wire brush your old bolt threads, your hub threads will still be corroded. Think about it!

But as Speedracer has said, you could consider chucking the used bolts away and using new ones. But as we are not refering to over-torquing here, the pre-load is still in the elastic range, so there's no need to replace them unless heavily corroded: which they won't be if you use anti-seize compound!!

The debate continues....

TThriller


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## John-H (Jul 13, 2005)

TThriller said:


> John, your a star! A great attempt to get some Math into the debate and qualify what you are saying. There are a few assumptions that should be quieried further. Refering to your points:


Thanks for the kind words  I spent some time trying to find some authorative published advice but ended up trying to work it out. You're right, I did make some assumptions and I'm glad someone's looking at them.



TThriller said:


> 1) Agreed. But another way a looking at the lateral forces on the wheels is to consider the g-force that the car can generate. 1.5 g should be easily acheieved: could do with a bit more research.


I've seen published coefficient of friction for rubber on solids vary from 0.8 to 4 and 0.4 for wet asphalt. I took 1.5 from a bikers website and thought it was probably reasonable for an individual wheel and considering shock loads.



TThriller said:


> 2) Agreed.


Where the shock loads come in when you hit a bump when doing this.



TThriller said:


> 3) Not quite right, more applicable to bolts without preload. As the bolts are all torqued up equally, the centroid of the clamping force is will be the centre of the bolts group, ie, the centre of the wheel. The fulrum will be the edge of the hub. Assuming a 6" hub as I've not got my wheels off, the lever arms are 9"and 3" so a ratio of 3.0, rather that 5.0. But this only illustrates another reason to pre-load the bolts correctly.


It was only an approximate measurement without taking the wheel off but I thought I'd measured 10" from the tyre edge to the bottom edge of the hub, then it was a further 4" to the upper bolt PCD, so a ratio of 5 taken from the centre to the lower hub edge. I'm taking my wheels off later so I'll measure it more accurately.



TThriller said:


> 4) This is where I do disagree with you. As I tried to explain earlier, the tensile force in a *correctly pre-loaded* bolts does not cycle up and down: it remains constant. The stress only cycles when the pre_load is exceeded. Hence the need to achieve the specified torque in the bolt to achieve the specified pre-load tension. The change in applied force only changes the contact stress across the joint in the connected parts. The forces you have applied John are all SLS, we should be looking at factored ULS forces. A factor of 1.5 should be about right. Which sort of gets us back to your forces.


You are quite right - some wooly thinking on my part  - how stupid of me thinking the bolt stress varies like that! It doesn't of course because in simple terms there is no movement of the clamped surfaces which is the whole purpose of preload exceeding service load :roll: - the bolt tension remains constant. As you say the stress varies in the clamped items instead. The bolt stress would only vary once movement occurs. There is some small movement, as the stress variation in the clamped materials does cause them to compress and bulge at the fulcrum point but this is microscopic in comparison to the bolt length so I was wrong to consider it significant.



TThriller said:


> 5) Agreed


Have a look here: Wheel stud failures

And here for some excellent information: Bolt Science website



TThriller said:


> 6) The equation I think you are refering to is "Given also that the TA will reduce the coefficient of friction from ~0.74 to 0.12 and increase the preload by something like a factor of five...". It has a componant missing: the friction under the bolt head seating. See if you agree John and try to build that into the equation to make it more realistic.


The equation I was referring to was this one:

F = T / [r . tan ( λ + φ )] , or rearranged, T = F . r . tan ( λ + φ )

T = Torque (Nm) 
F = Tensile force (N) 
r = bolt radius (m) 
λ = Thread angle, ArcSin(Pitch/bolt circumference) (degrees) 
φ = Friction angle arctan(μ) where μ is the coefficient of friction.

It's only a simplification (which amused Wak!) and yes it doesn't include the bolt head. This link gives a more comprehensive analysis:

http://www.roymech.co.uk/Useful_Tables/ ... ews_1.html

If I get time I'll try to adapt it 



TThriller said:


> But generally John, a very good attempt to justify your (our) argument.
> 
> Pity you didnt post this before the Poll
> 
> ...


Thanks and I agree with your other points - sorry I didn't post it earlier but it was the vote going the other way which spurred me :lol:

By the way, to correct an earlier reference CopaslipÂ® is made by Molyslip and CoppereaseÂ® is made by Comma - both very similar as far as I know.
http://www.molyslip.co.uk/antiseize.html
http://www.commaoil.com/


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## garvin (May 7, 2002)

John-H said:


> Here's an argument:
> 
> 1/ The coefficient of friction (Âµ) of good rubber tyres on dry ashphalt is around 1.5 or even higher.
> 
> ...


Nice one, but the case needs further development I feel before you will convince me (although I believe the specialist compunds are OK). What about the forces in the 'flexible' tyre and the point at which the tyre then slips - it's not on rails! The weight of the car will never be on one wheel only, although as an approximation a fully loaded car could put about one tonne through a single wheel I suppose. i.e. what are the maximum 'real world' forces possible. The forces in the bolt/hub thread need to be addressed as well - how many 'threads' are taking the loads and what is the maximum they can tolerate when torquing up before the elastic limit is 'breached' i.e. where is the point that the loading is too high? It would also be interesting to see where the use of general purpose grease would put the pre-load!

While we're at it, it would be interesting to see the effects of someone not using a torque wrench but using the Audi provided wheel bolt wrench - from my calculations it would be possible for a 12 stone bloke to generate as much as 190Nm torque (doing it up as tight as they could - even more if they jump up and down on it or use some other uncalibrated socket/wrench). Anyone know the coefficient of friction for general purpose grease?


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## MikeyG (Sep 17, 2005)

OK - I'm convinced John, and TThriller.

On Garvin's last point: you seem to be arguing against John's exposition based on the idea that his calculations are 'worst case', and that such a high force won't result, since the tyres will deform, etc. This, however, is not an indication _in itself_ that lubricating the threads is 'bad' or 'not worthwhile'. John's calculations indicate that a higher margin of safety is achieved by use of lubricant on the threads - they don't _need_ to prove that a dry thread is actually unsafe, as such (imho) - that's a slightly different debate.

To be pedantic about the poll: I voted "No", since the question asks "Do you grease your wheel nuts", and since I don't lubricate them.... Were the question to be "Do you think that you should [grease your wheel nuts]?" or "Will you grease your wheel nuts in future if someone tells you where to get hold of TA paste, or whatever it's called?", then in that instance I'd answer "Yes, I'm convinced!"


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## John-H (Jul 13, 2005)

garvin said:


> ...Nice one, but the case needs further development I feel before you will convince me (although I believe the specialist compunds are OK). What about the forces in the 'flexible' tyre and the point at which the tyre then slips - it's not on rails! The weight of the car will never be on one wheel only, although as an approximation a fully loaded car could put about one tonne through a single wheel I suppose. i.e. what are the maximum 'real world' forces possible. The forces in the bolt/hub thread need to be addressed as well - how many 'threads' are taking the loads and what is the maximum they can tolerate when torquing up before the elastic limit is 'breached' i.e. where is the point that the loading is too high? It would also be interesting to see where the use of general purpose grease would put the pre-load!
> 
> While we're at it, it would be interesting to see the effects of someone not using a torque wrench but using the Audi provided wheel bolt wrench - from my calculations it would be possible for a 12 stone bloke to generate as much as 190Nm torque (doing it up as tight as they could - even more if they jump up and down on it or use some other uncalibrated socket/wrench). Anyone know the coefficient of friction for general purpose grease?


The maximum bolt torque depends on the grade 8.8 or 10.9 12.9 etc. There is no marking on the TT bolts because they are socket head. As you can see from here:

Bolt Torque Chart

An M14x1.5mm 8.8 bolt is 150Nm and 10.9 grade is 205Nm. These figures are within the elastic limit of the bolt.

There will be enough threads involved according to common fastener practice to match the bolt especially when you consider that female cut threads are inherently weaker than rolled bolt threads and you always want to replace the bolt first.

I agree that standard grease should not be used. It will melt for a start and possibly give you a coefficient of friction nearer oil. I've always used Copaslip/Copper Ease for those reasons.


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## mav696 (May 21, 2006)

John-H said:


> garvin said:
> 
> 
> > ...Nice one, but the case needs further development I feel before you will convince me (although I believe the specialist compunds are OK). What about the forces in the 'flexible' tyre and the point at which the tyre then slips - it's not on rails! The weight of the car will never be on one wheel only, although as an approximation a fully loaded car could put about one tonne through a single wheel I suppose. i.e. what are the maximum 'real world' forces possible. The forces in the bolt/hub thread need to be addressed as well - how many 'threads' are taking the loads and what is the maximum they can tolerate when torquing up before the elastic limit is 'breached' i.e. where is the point that the loading is too high? It would also be interesting to see where the use of general purpose grease would put the pre-load!
> ...


I think you would have to assume that it would be a tensile strenth of 8.8 for the bolt, you mention there will be enough threads involved well on a M14 bolt you lose the effectiveness after 21mm so it can be a lot longer and it will not make much difference.


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## garvin (May 7, 2002)

MikeyG said:


> On Garvin's last point: you seem to be arguing against John's exposition based on the idea that his calculations are 'worst case', and that such a high force won't result, since the tyres will deform, etc. This, however, is not an indication _in itself_ that lubricating the threads is 'bad' or 'not worthwhile'. John's calculations indicate that a higher margin of safety is achieved by use of lubricant on the threads - they don't _need_ to prove that a dry thread is actually unsafe, as such (imho) - that's a slightly different debate.


I'm not arguing that at all - I have no problem with specific thread compunds designed for the job (although I'm reviewing that on the basis of the vastly reduced friction they offer and higher pre-load for same torque - see below). I'm simply coming from a point of view that you need the pre-load to exceed the maximum 'dynamic' load applied to always prevent a gap opening up between the wheel and hub, otherwise the bolt is very likely to fail. In practice I do not think this approaches the values of John's calculation due to the fact that the tyres just cannot generate the amount of grip necessary to achieve them. Therefore, the dry thread clamping force has sufficient safety margin IMHO (as long as it is clean and the 'residual' tightening torque of the bolt is small - that's the torque required to overcome the 'crap' in the threads - which is why I advocate cleaning them and ensuring that they can easily be hand tightened).

Having applied a safety marigin you want to stay well away from the point where the bolt itself may fail due to the tensile forces. OK, so I can accept that even with the specific thread compound applied this may well be the case however, I am now very conderned at the much higher load applied, via the 'wedged' shoulder of the wheel bolt, to the, much softer, alloy wheel. If the load is too high then cracks may start to appear around the holes in the wheel and a whole lot of trouble may ensue. I'm afraid I have no idea how to accurately calculate the failure load of the wheel but I'll bet it is a lot closer to the 11.29 tonnes than then 2.20 tonnes of John's calculations.

I'll think I'll stay at the lower end with a reasonable safety margin :wink:


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## John-H (Jul 13, 2005)

I found some interesting tables:

*STRENGTH OF STEEL BOLTS 
class no. 4.6 5.8 8.8 9.8 10.9 12.9 
Su MPa 400 500 800 900 1000 1200 
Sy MPa 240 400 640 720 900 1080 
Sp MPa 225 380 590 650 830 970 *

The Su figures are the ultimate stress at failure and the Sy figures are for 0.2% offst yield (start of plastic deformation). The Sp figures are "proof stress" figures which is the largest stress a bolt can take within it's elastic limit before plastic deformation.

For the M14x1.5 bolt the minor diameter is the stress area = 116.13mm^2

So, from Stress x Area = Force, we get:

*PROOF TENSION OF M14x1.5 BOLT
class no. 4.6_ 5.8_ 8.8_ 9.8_ 10.9_ 12.9
Tonnes 26.2 44.1 68.5 75.5 96.37 112*

Given that the wheel bolts are at least going to be 8.8 grade and that the maximum tension you could get from 120Nm torque with even zero friction is ~50 Tonnes, then 68 Tonnes of proof tension is a good safety margin against permanent bolt stretch. Given that a more realistic friction using Antiseize grease gives you nearer 12 Tonnes tension then your safety margin is enormous. 

I'd be more worried about wearing your threads out by not lubricating them :wink:


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## TTCool (Feb 7, 2005)

The NO's are winning, Yeah.


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## TTCool (Feb 7, 2005)

John

Are you sure this info is not from the 1960's. :lol:

Isn't it great to be able to banter with friends 

Joe & Judy


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## John-H (Jul 13, 2005)

I've finished my lunch now Joe and am returning to the job. I'll try not to get my nuts cross threaded like this conversation :wink: :lol:


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## garvin (May 7, 2002)

John-H said:


> I found some interesting tables:
> 
> *STRENGTH OF STEEL BOLTS
> class no. 4.6 5.8 8.8 9.8 10.9 12.9
> ...


Using my 12 stone bloke generating a maximum of 190Nm torque using the Audi supplied wheel bolt wrench then I calculate that the clamp loads will be ~47 tonnes for oil lubrication, ~18 tonnes for Optimol lubrication and ~3.5 tonnes for clean dry threads. On this basis it doesn't seem to matter what lubrication you use as, being worse case (the residual friction and friction of the bolt shoulder is not taken into account in these calculations), it seems very highly unlikely that the bolt itself can be overloaded.

So two questions remain:-

1. Can anyone confirm that the wheel bolts are actually 8.8 grade or higher?

2. When does the alloy wheel give up the ghost .................... could give a whole new meaning to the term 'split rims' :wink: I have seen alloy wheels split around the bolt holes due to obvious overtightening - although mainly as a result of using an air hammer to do the bolts up. Anyone care to find out/calculate the maximum load the alloy wheel can take?


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## John-H (Jul 13, 2005)

Interest you shoud say that - when I first took my wheel bolts off, standing on a 18" breaker bar didn't shift them. I had to lift the bar, so greater than my own weight and when it went bang and I fell over and I thought the bolt had sheared :lol: Luckily they are strong enough to take the abuse.


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## garvin (May 7, 2002)

I have tried to incorporate the collar friction and my research has turned up the following expression:-

*T = Fp.r.[(p + π.μt.d.sec(α/2)) / (π.d â€" μt.p. sec(α/2))] + Fp.μc.R*

Re-arranging we get:-

*Fp = T / (r.((p + π.μt.d.sec(α/2)) / (π.d â€" μt.p. sec(α/2))) + μc.R)*

Where:-

T = Torque (Nm) = 120Nm
Fp = Pre-load (N)
r = Thread radius (m) = 0.007m
p = Thread pitch (m) = 0.0015m
μt = Coefficient of friction for thread (steel on steel 0.14)
d = Thread diameter (m) = 0.014m
α = Thread angle (degrees) = 60 degrees for standard high tensile metric bolts
μc = Coefficient of friction for collar (steel on aluminium â€" sliding = 0.47)
R = Collar friction radius (m) ~ 0.0127m

Interestingly, the thread friction coefficient, μt, is one I have found specifically defined for steel threads giving a range 0.12 to 0.18 (very different from the standard steel on steel figures!!) so the average value has been taken. This probably explains why Optimal TA at 0.12 specifies that the torque values need not be changed!

The collar friction coefficient, μc, at 0.47 is taken as quoted for steel â€˜slidingâ€™ on aluminium â€" although the wheels are an alloy so the actual value is likely to be different!

The collar friction radius, R, I have approximated, from examining a bolt, assuming a 45 degree collar angle and a collar diameter at the top of 22mm and also assumed the face is flat even though it is domed.

This yields the following (assuming my maths is correct):-

Maximum pre-load possible, assuming all friction is zero ~ 51.3 tonnes

Pre-load using 'oil' on threads and collar ~ 24.6 tonnes

Pre-load using Optimol TA on thread and collar ~ 4.5 tonnes

Pre-load assembling clean dry threads and collar ~ 1.7 tonnes

By applying Optimol TA on collar only the pre-load is ~ 4.3 tonnes

From this it can be seen that it is the collar that dominates proceedings and I would contend that using an anti-seize compound with a coefficient of friction around 0.12 is OK. However, stay away from oil and, probably, 'common or garden' grease.


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## John-H (Jul 13, 2005)

Good stuff Garvin!  Yes, the dry thread μ is the subject of some variation depending where you look. Hard steel on hard steel is supposed to be 0.74 or so, so you'd think that would apply to a dry bolt but I've also seen figures for a bolt quoted as of around 0.15 to 0.25 or one reference that said 0.4 for "degreased" steel :?


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## mav696 (May 21, 2006)

So did anybody find out where we buy the TA Paste?


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## John-H (Jul 13, 2005)

Not sure, maybe a good motor factor or there is Copaslip or CopperEase which I think are much the same and you can get them from many places including Halfords.


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## garvin (May 7, 2002)

mav696 said:


> So did anybody find out where we buy the TA Paste?


Good question. Seems that BMW and Porsche recommend this stuff as well as Audi (who say to only use this and nothing else) yet it is difficult to find it via Internet searches. I can only presume that an Audi Dealer must be able to get it - anyone know and, more importantly, how much it costs?


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## Rene Pogel (Aug 27, 2015)

Sorry to resurrect an ancient thread, but I came across the answer to the last question posted - where to get Optimol TA, the paste used to "rebuild wheels" (ie. to lubricate wheel bolts with).

Moto-Bins in the UK stock it for a very reasonable price, I just ordered a can: https://www.motobins.co.uk/displayfinal ... ch=1&go=GO

Hope this helps someone.


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## John-H (Jul 13, 2005)

Very kind to let everyone know


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## YELLOW_TT (Feb 25, 2004)

John it's spam he's advertising BMW bikes


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## John-H (Jul 13, 2005)

Seems genuine Andy. Optimal-TA is used on BMW bikes - see this link here which specifies the same supplier in the UK:

http://www.i-bmw.com/showthread.php?t=27172

Also Rene Pogel and all his other details have no history of spam so he looks genuinely helpful. Thanks for keeping an eye out for spam though - can't be to careful


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## IC_HOTT (May 29, 2010)

barton TT said:
 

> Think it 120 Nm if i remember right. :?


+1 for this with no lube of any sort.

of course your typical wheel changer at garages makes sure they are at approx 500 Nm to make 'sure' they dont come off :evil:


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## DC240S (Sep 24, 2014)

IC_HOTT said:


> barton TT said:
> 
> 
> > Think it 120 Nm if i remember right. :?
> ...


+ 1 on the 500nm!

After a year of ownership and two destroyed replacement lock nut keys I now have removable wheels! -

Thanks Peterborough Audi for carefully sorting it.


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## John-H (Jul 13, 2005)

Here's a graph of wheel bolt preload vs. coefficient of friction. Audi specify the bolts torqued @ 120Nm coated with Comp-TA which gives over 11 tonnes of preload for each bolt. Torqueing the bolts dry will result in loose wheel bolts with a fraction of the preload. It's the preload that prevents wheel cyclic movement relative to the hub which works bolts loose. Conversely you don't want to oil or grease your bolts either as you will well exceed the design preload.


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## 3TT3 (Aug 30, 2014)

I use 105 nm on my "tuner bolts"

1. cos thats what I use to bolt on the pcd adapter plates

2. Cos I dont want to strip the tread on the alloy pcd adapters

3. Cos they dont come loose at that torque

4. cos I nearly have to bitchslap tyre wheel fitters not to use compressed air wrenches.
One set of wheel changes and my and my tuner bolt adapter is destroyed 

A good quality 12mm hex/allen key will last.. but do not give internal socket "tuner bolt' wheels to a tyre fitter unless you supervise and make sure they dont use the air gun.
The air gun will destroy the internal socket of tuner bolts even on "small fart" setting.

I use brake cleaner spray on rust dusted wheel bolts n thas about it.


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## IC_HOTT (May 29, 2010)

John-H said:


> Here's a graph of wheel bolt preload vs. coefficient of friction. Audi specify the bolts torqued @ 120Nm coated with Comp-TA which gives over 11 tonnes of preload for each bolt. Torqueing the bolts dry will result in loose wheel bolts with a fraction of the preload. It's the preload that prevents wheel cyclic movement relative to the hub which works bolts loose. Conversely you don't want to oil or grease your bolts either as you will well exceed the design preload.


point understood John, so what is Comp-TA and who actually uses it - no tyre exchange facility Ive ever known !


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## Rene Pogel (Aug 27, 2015)

Hey,

Whaddya mean, "spam"? I'm relatively new here, simply because I just bought my first TT a few weeks ago. So far, loving it!

No, honestly, I just came across Moto Bins as sellers of the paste. I ordered a can (I live in Holland), it arrived today - great service.

As to whether you should apply any kind of compound, and if so what, I'll leave that to those wiser than me. In the meantime, Audi seem to think that I should, so I suppose I'll just go along with what they say.

In case anyone's curious about the nickname, I thought it applied pretty well to TT's. At least, when spelled backwards...


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## Hoggy (May 8, 2002)

Hi, Over 50 years of driving, never used a torque wrench on my wheels, always coppaslip the thread & never had a problem.
Always remove & replace my locking bolts, valve caps & centre caps. Don't trust those tyre fitters, it's no good moaning afterwards.
Hoggy.


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## 3TT3 (Aug 30, 2014)

Hoggy said:


> Hi, Over 50 years of driving, never used a torque wrench on my wheels, always coppaslip the thread & never had a problem.
> Always remove & replace my locking bolts, valve caps & centre caps. Don't trust those tyre fitters, it's no good moaning afterwards.
> Hoggy.


Thas ok Hoggy but the "years of experience" come into it.
If youve used greased threads and no torque wrench, you know by feel.
Many of us would know by feel the diff between say 40 and 80 on the same length lever and I used to grease my wheelbolts too at one time  but when I started using a torque wrench years back.."this cant be right?" and so on.


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## John-H (Jul 13, 2005)

I saw a mechanic in a tyre bay use a torque wrench once.. He looked up the torque, set the wrench, tightened the wheel nut until the torque wrench went click and then gave it an extra hard heave to make sure it was right  I hope he doesn't build engines :lol:


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