Club 80-90 Forums

Should the wheel nut torque be reduced when alloy wheels are fitted?
I have the 14 inch VW 'pepper pot' alloys (thanks Printeral) which were I believe an extra on some Caravelles, and my neighbour opposite who is an irritating 69 year old boy racing petrolhead know-it-all, says the torque should be lower than the standard, which Haynes lists as 125 ft/lbs, and which I find a bit eyewatering even on steels. Incidentally why (Haynes again) should my Bay window have a recommended 94 ft/lbs torque when the steel wheels,hubs,studs and nuts are the same as the T25/T3?
Can anyone help or point me in the right direction? I have Googled 'till I'm goggle eyed!
Reminds me of an old hand I used to work with who said "The torque wrench was invented to enable unskilled labour to do a skilled job!"

Mike

As youve had no replies-I think it is a case of common sense--I keep a 2 foot breaker bar & 19mm impact socket in me van--do ya wheel nuts up fairly firmly with one of these & yool be ok--

Thanks stuckin88,
It was more a case of giving the smart a*** across the road some facts. He knows everything! It is an ongoing battle of wits. He is a complete buffoon, cloned from Captain Mainwaring. I am not a bit worried about the torque of my wheel nuts, they are not going to cause me half the trouble that the nut across the road does!
Thanks again.
Mike

Customers wince when I rattle their wheel nuts up with the air gun, they've been reading too many forums!
What makes them think twice is when I get the torque wrench out and torque their wheels to 180nm as per book and I have to swing on the torque wrench, making tighter what they believed to be undo-able from the gun!
Maybe the higher torque as opposed to the bay is the weight carrying capacity and the weight of the van itself. The track and wheel base are all different too.

This subject has been worrying me for a bit as well.
The last thing I want to do is crack, split or I dont know what to my new rims as they are brand spanking new.
What torque does an air gun tighten them too? if it's less than the manual says, I would rather tighten them to the same as the gun.
lhd...................

Incidentally why (Haynes again) should my Bay window have a recommended 94 ft/lbs torque when the steel wheels,hubs,studs and nuts are the same as the T25/T3?

Simon's right, this is because the weight of the van is greater. This may sound either silly to some or obvious to others, but in reality, nuts and bolts are done up to clamp two or more parts together - the nut not coming off is taken for granted when torqued up to the correct figure, and is only much of a design a consideration in some cases, usually lightly clamped parts. Wheel nuts and recesses are tapered, so at anywhere near the correct torque figure, they're highly unlikely to loosen.

But the aim is firstly to provide a clamping force calculated as appropriate, and in cases of fluctuating and even reversing loads such as a wheel, the clamping force reduces the chance of fatigue failures by creating a high static-stress level (e.g. pre-loading). This is probably the case with wheel bolts and studs.

Between 1/2 and 2/3 of the torque figure frequently goes into friction in the threads and the bolt or nut bearing face, so as little as 1/3 produces the clamping force.

I too usually carry a powerbar and 19mm impact socket on board and use it much like Stuckin says.

Knowing that the threads are cleaned and lightlty lubed with anti-seize whenever they come off tp keep corrosion in check, and that the hub face and back of wheel is also checked and cleaned, I usually torque not much over 100 ft-lbs* on 15" steels on a Syncro, that can have at least a ton in the back from time to time. 133 is what Bentley says, so knowing that they're clean and the wheel's nicely flat against the hub, I expect I'm easily getting the minimum clamping force that VW hopes for under worst case conditions, doing them up in stages to get everything seated nicely.

Alloy wheels often have a larger and different tapered contact area to reduce local bearing stresses. You might follow the same thinking, that if the threads are well brushed clean, the tapers aren't knarled and corroded and the nuts run up nicely, you needn't go berserk with the powerbar or torque wrench. But done up to not come off, isn't the only criterion! The clamping force should be much the same as with steels, so also make sure the backs of the wheels and hub faces are clean, flat and not corroded badly, do them up to 100 lb-ft and worry not. But be sure to tighten them in a star pattern in 2 or 3 stages, unequal torques are definitely a bad thing on fronts, due to the potentila for disc warping.

*

If you insist on lubricating lug threads, please be sparing and make sure to compensate for the increased torque likely to result. For example, one lubricant manufacturer recommends torquing nuts to only 85 percent of the factory specification when using their nickel-based anti-seize compound on threads.

from http://www.volvoclub.org.uk/faq/WheelsT ... teelWheels


For more, see the link at the bottom of Wiki on Torques

Thanks Clive and Simon,
Glad to get some views on the subject from technical people.
I had read the Volvo forum comments on alloys versus steel, and this was my only defence against my know it all neighbours statement that he could assure me that I was wrong to use the same torque for my alloys as the steels.
Point taken that the Wedgie is heavier than the Bay, and dimensions also differ.
Neighbour has a Mini Cooper S with all the boy racer trimmings, high lift cams, ratio rockers, racing clutch, straight cut gears, etc. etc. sounds bloody awful. The local garage says they can hear him coming, but don't have time to hide!
Mike

The original Cooper 'S' with straight-cut box? - if so, what a super (and noisy) box, ask him for a drive, call his-bluff
Once you're moving forget the clutch, see what he thinks of that! Should be able to drop down into 3rd around 90ish if you give it a healthy bootful coming through neutral - so put your hand over the revcounter at that point - hehe! Should quieten him down for a week or so

Just to add a couple of small things.

Get a good fitting quality socket, six sided are best (imo) less chance of rounding the nut/stud although if the nuts/studs are good quality then shouldn't be too much of a problem.

Main problem with over tightning is stripped threads, again less likely with quality parts, we have to test our own produced nuts and always exceed stated proof load test specified in the standards.

As stated above, give um a good clean and also inspec the treads for damage, if damaged replace.

Cheers

Andy
AMC (UK) Fasteners Ltd - Steel Nuts Manufacturers...

Main problem with over tightning is stripped threads

That may be true if you mean 'most common problem' but from an engineering and safety perspective a problem like that is pretty self-evident to even the most unobservant so it's nothing like as dangerous as overtightening or unequal tightening (without stripped threads) can be... lost wheels or distorted hub flanges.