That's the point, you shouldn't be using them as a breaker bar so that wouldn't come under "using properly"
- Thread starter bigegg
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That's the point, you shouldn't be using them as a breaker bar so that wouldn't come under "using properly"
No, using them as a breaker bar is not using them properly.
Ideally the fixing should be moving before it reaches the required torque and it should be reached in a smooth steady movement.
I swapped the wheel front to rear on my V70 today, had a vague recollection that the torque setting was 120NM so put them to that. When I checked were supposed to be 140NM. I reseat the torque wrench to 140NM and every single bolt clicked with no movement at all. This just shows how important correct use is
I swapped the wheel front to rear on my V70 today, had a vague recollection that the torque setting was 120NM so put them to that. When I checked were supposed to be 140NM. I reseat the torque wrench to 140NM and every single bolt clicked with no movement at all. This just shows how important correct use is
indy4x
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There was an article in CCC many many years ago around how to use a torque wrench and from memory they general advice was
Use as few extension bars as possible, preferably none
Ensure threads are super clean and lubricated unless thread lock is used
Take it slow, as your approaching the specified torque keep your angular movement slow and steady
As higher torque values, most of the torque is overcoming friction on the threads
There was more but I'm going back 30yrs
Use as few extension bars as possible, preferably none
Ensure threads are super clean and lubricated unless thread lock is used
Take it slow, as your approaching the specified torque keep your angular movement slow and steady
As higher torque values, most of the torque is overcoming friction on the threads
There was more but I'm going back 30yrs
Lubrication is a tricky subject.
In some applications oiling threads will lead to stripping.
30 years ago almost everything was iron, which is why I use a torque wrench all the time now as aluminium never feels tight.
The thing to remember is that it's not the nut or bolt you want tight, it's the clamping force between the two secured surfaces
Fast car did an article on this in the 80s or 90s and the differences can be truly huge between lunrication and other methods or not.
Guess that's why some many things are torque +degrees
Easier to get to a consistent low torque then degrees to ramp it up constantly to the clamping force
In some applications oiling threads will lead to stripping.
30 years ago almost everything was iron, which is why I use a torque wrench all the time now as aluminium never feels tight.
The thing to remember is that it's not the nut or bolt you want tight, it's the clamping force between the two secured surfaces
Fast car did an article on this in the 80s or 90s and the differences can be truly huge between lunrication and other methods or not.
Guess that's why some many things are torque +degrees
Easier to get to a consistent low torque then degrees to ramp it up constantly to the clamping force
whm_fab
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critical threads that are torqued to spec shouldnt be lubricated unless indicated to do so, they should be dry and clean.
only if indicated by the manufacturer of the bolt/part/car should you oil/grease etc.
on non critcal stuff we all like to copper grease anti-seize things, but in this case ESPECIALLY wheel nuts/bolts should be clean and dry.
the reason why manufacurers would tell you to lubricate bolts or studs etc is to make results as consistent as possible by reducing preload scatter, and make the part to suit this.
when you set your torque wrench to a predetermined level, apply torque incrementally, and assume all is well when the wrench goes click. Problem is a great deal of the energy exerted in tightening the fastener merely overcomes friction from thread engagement, the underside of the bolt head or nut, and the fastener lubricant itself (oil, molygrease, copper lube, etc. all have different frictional values). Typically, the desired preload is not achieved, usually over stretching the bolt beyond its yeild point.
whats important to understand is that fasteners act much the same as a spring, given the physics of stretch and rebound. A stud or bolt must be stretched to produce clamping force. its not the 'tightness' of the threads agaist each other like alot of people think. For example, a typical 3/8” con rod bolt will need to be stretched about .006” to provide 10,000 lbs of force. and normally when this is done, it feels dangerously undertighened.
i use a stretch guage for rod bots, as this is the only sure fire way to overcome all other variables
only if indicated by the manufacturer of the bolt/part/car should you oil/grease etc.
on non critcal stuff we all like to copper grease anti-seize things, but in this case ESPECIALLY wheel nuts/bolts should be clean and dry.
the reason why manufacurers would tell you to lubricate bolts or studs etc is to make results as consistent as possible by reducing preload scatter, and make the part to suit this.
when you set your torque wrench to a predetermined level, apply torque incrementally, and assume all is well when the wrench goes click. Problem is a great deal of the energy exerted in tightening the fastener merely overcomes friction from thread engagement, the underside of the bolt head or nut, and the fastener lubricant itself (oil, molygrease, copper lube, etc. all have different frictional values). Typically, the desired preload is not achieved, usually over stretching the bolt beyond its yeild point.
whats important to understand is that fasteners act much the same as a spring, given the physics of stretch and rebound. A stud or bolt must be stretched to produce clamping force. its not the 'tightness' of the threads agaist each other like alot of people think. For example, a typical 3/8” con rod bolt will need to be stretched about .006” to provide 10,000 lbs of force. and normally when this is done, it feels dangerously undertighened.
i use a stretch guage for rod bots, as this is the only sure fire way to overcome all other variables
aguycalledsteve
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This is the thing with wheel nuts. Why people feel the need to tighten them so tight you have use alot of mechanical advantage to get them off.
If SWMBO took my car out and got a flat tyre and those breaker bars and poles weren't in the car, she would be 100% stuffed. Potentially costing 100's to get recovered for the sake of a flat tyre that if it were torqued correctly would have been able to have been done at roadside.
MoreWellie
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I have heard this a lot but they make minimal difference (unless they are spring based flexy ones of course)
NEVER use a Universal joint with a torque wrench
clift_d
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New studs should always be pressed into the hub, not pulled into place by tightening, otherwise you will over stress them before you've even started.
As above most vehicle manufacturers require that wheel stud threads are not lubricated, to avoid over-torqueing of the wheel nuts. If you really feel you need to put something on the threads to prevent corrosion then use a small amount of a low strength thread locker like Loctite 222.
+1 for always using a torque wrench for final tightening.
As above most vehicle manufacturers require that wheel stud threads are not lubricated, to avoid over-torqueing of the wheel nuts. If you really feel you need to put something on the threads to prevent corrosion then use a small amount of a low strength thread locker like Loctite 222.
+1 for always using a torque wrench for final tightening.
bigegg
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PhillipM
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Whilst clean, dry studs are ideal, usually after a few years the surface corrosion on the threads, and the nut face biting into wheel coating makes torque scatter an issue.
In which case a small amount of good antisieze will bring the scatter down much more than the change in K value will effect the outright clamping load.
(Especially if a few garages have done things up to FT with the wheel guns and stretched things a little - or as per OP heaved on them with a bar. Overtorqued wheel nuts cause more failures than loose ones, and they're a sudden failure rather than a graceful one. Not to mention you can even distort the hub itself on some cars.)
If you don't have a press to put a stud in, nip them up with the nut to the torque spec, or even less, just to get it nipped, then smack the back of the stud with a mallet. Rinse and repeat until seated.
In which case a small amount of good antisieze will bring the scatter down much more than the change in K value will effect the outright clamping load.
(Especially if a few garages have done things up to FT with the wheel guns and stretched things a little - or as per OP heaved on them with a bar. Overtorqued wheel nuts cause more failures than loose ones, and they're a sudden failure rather than a graceful one. Not to mention you can even distort the hub itself on some cars.)
If you don't have a press to put a stud in, nip them up with the nut to the torque spec, or even less, just to get it nipped, then smack the back of the stud with a mallet. Rinse and repeat until seated.
indy4x
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@MoreWellie Useful video, I do wonder if the same hold true of higher torque values, would you be able to hold the head steady with a bunch of extensions while giving it say 250Nm or more
I have used extensions when there is no other option and do as per the video and support the ratchet head
I have used extensions when there is no other option and do as per the video and support the ratchet head
Farside
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Hah. Lack of press means you'd be lucky if they were BFHd instead. Otherwise, pulling into place was the norm, even though it's not the right way to do it. Luckily, most wheel studs back then were a bit meatier.
123hotchef
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I always torque my lug nuts up
postie jon
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Oh well
I'm sure I'll snap another one at some point.
I'll remember the above then...
remember stopping at the roadside to help an elderly gent who had a puncture, he also had just lately been released from hospital after a large stomach op, anyway he had a saab, so got out his jack , spare wheel and wheel key, blimey took most of 45mns to get the nuts off ,tottally solid right to the end , then another 30 to put them on again , never seen a clean or lube in its life, got the job done ,wheel back in boot tools laid past, he got back in the car, just as he drove off he says o i could have got the rac to do it, "BYE" .......
did the same with a young lady ,she was a salvation army member, had ran her Ka until the wheel was square, and her spare was flat ,took her to the local kwik fit as i was passing the door. different story.....
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Pete.
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If you take apart a torque wrench and watch how it works you'll see that (for the majority of them) after they click the rocker hits a solid stop so the whole thing effectively becomes a solid bar. Pushing it past the click or using it in reverse puts zero load on the torque measuring system so it should have no detrimental effect unless you get really animal on it and bend the tool permanently. They are symmetrical too so using them for undoing works exactly the same as doing them up.
I've got two identical Draper torque wrenches, one that I got new the other came directly from calibration at Draper. I keep the calibration one solely for checking the workshop one and it hasn't changed since about 2007 when I got them both and I use mine for un-doing stuff all the time.
I've got two identical Draper torque wrenches, one that I got new the other came directly from calibration at Draper. I keep the calibration one solely for checking the workshop one and it hasn't changed since about 2007 when I got them both and I use mine for un-doing stuff all the time.
