Torque settings
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Cheers David, but forgot to mention I've got r&g frame sliders on so might be slightly different but I think the vibes I've been feeling are that my bolts have been re-torqued by the Ducati mechanic to about 10nm!! I could spin the slider with my hand wtf! Just checked the service sheet and it says they checked it or should I say slackened it.
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I blame the educational system. We're more and more conditioned to "get a degree" instead of learning a trade. It's really hard for shops to hire good mechanics nowadays.
Being a mechanic isn't considered "cool", instead we should all get an MBA or a degree in Liberal Arts...
(ever tried to find a really good mechanic or carpenter?)
/rant
Being a mechanic isn't considered "cool", instead we should all get an MBA or a degree in Liberal Arts...
(ever tried to find a really good mechanic or carpenter?)
/rant
Even if you have the R&G frame sliders, torque value shouldn't change, unless you changed bolts. What matters in a bolt connection is a pretension in bolt, which is being achieved while tightening. The pretension should be equal to around 90% of an yield strength of a bolt, otherwise it will simply get loose. You have to imagine that a bolt actually works like a spring - if the proper level of a pretension is not achieved, spring force is too low and bolts start to loose (this is a very simplified explanation). That is why using torque wrenches is very important, especially in places where everything constantly vibrates and constantly expands/ shrinks due to temperature changes.
Before re-torquing, make sure that the bolts threads are greased. Grease helps to decrease a friction coefficient between a female and a male thread - if the friction coefficient is too hight (not greased, dirty threads etc.), you will not achieve proper pretension, even thought your torque wrench will indicate that you did (think about rusted bolts and how hard it's to bolt them sometimes).
Hope my explanation is clear enough
That is why I always do a maintenance on my own. Wherever I go, mechanics always do something wrong with my bikes... I lived in 4 different countries so far and everywhere is exactly that same - doesn't matter if it's Ducati or Harley.
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ONLY grease threads if the manual prescribes so. Else you're actually over torquing.
On dry, clean threads about 40% or so of the applied torque is lost in friction. When you grease the threads this number lowers to around 15%...
That's why I attached a snap from the service manual, as a confirmation of my words
Torque settings are nearly always quoted ‘wet’
It’s just as important to lube the face of the bolt head as well as the threads to achieve the proper tension.
If it was all that critical then manufactures would move over to a more reliable angular setting. The main objective is to be tight enough but more importanly is for multiple fasteners to be equal.
Torqueing bolts is actually not always to make sure they are tight, ‘Too’ tight is much worse as when the ape swings off the wee spanner the bolt reaches its ‘plastic’ stage and renders it slack and stretched.
It’s just as important to lube the face of the bolt head as well as the threads to achieve the proper tension.
If it was all that critical then manufactures would move over to a more reliable angular setting. The main objective is to be tight enough but more importanly is for multiple fasteners to be equal.
Torqueing bolts is actually not always to make sure they are tight, ‘Too’ tight is much worse as when the ape swings off the wee spanner the bolt reaches its ‘plastic’ stage and renders it slack and stretched.
Wouldn't agree here. Max Kool is more correct here:
For cylinder heads and most internal parts of engines your statement is correct. But for body, chassis, brakes and everything else not really.
Best example is lug bolts. Car manufactures give us a torque value but never say to lube bolts. And that's why greasing lug bolts with copper grease is a big mistake.
LOL
For a start copper grease is not a lubricant, it’s an anti-seize.
I presume a frame bolt is not inside an engine ??
The whole oil & gas industry must wrong too and I’ve been wrong for 40 odd years, who would’ve guessed. Maybe I’ll get my engineering colleagues to read and learn from this. LOL
LOL Copper grease is not a lubricant but it decreases friction coefficient between materials. And this friction coefficient is the most important.
LOL it is not. It is outside of it.
No, they are not wrong. You are, as you don't fully understand the topic.
I studied bolt connections for a while, as I am a mechanical engineer (working in nuclear research) and I calculate torque values quite often. You would be surprised how complex and advanced research has been done on it.
I understand fully, despite your arrogant assumption about my knowledge on the topic. In fact I’ve probably forgotten more than most people have learnt. Strange how you say my collegues are correct but then you say I’m wrong when actually I say exactly the same as them.
It’s been verified that Ducati recommend lubricating the bolt/nut but then ‘you’ say not to as it would only be inside an engine that it applies to. WTF.
Anyway, I’ll carry on doing it my way and you keep doing whatever it is you think best.
I am an active member on few forums and you are the first one I have ever been arguing with (unfortunately this is not the first time). You don't want to accept any other opinion than your own. For me you are very conceited. But this is only my opinion.
Coming back to the topic - read again what Max Kool and myself wrote and please, do your best to understand it.
And my assumption wasn't arrogant, it was simply based on this what you wrote.
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Fellas!
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This says it all. This is just physics. Knowing this (and accepting the above is true) automatically means you need to know if a torque value needs to be applied wet or dry. That's engineering 101. A typical mechanic's handbook specifies all bolts/nuts to be torqued dry, unless specified otherwise.
Torquing a bolt wet to the dry torque value could actually strip threads and break bolts very easily.
And we haven't even touched on "stretch torquing" or torque testing of nylock nuts for instance....
Let's take our meds and move on. :biggrin-new:
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Sorry guys didn't want to start a fight but thanks for all your comments and let's see what Ducati says.
What if the mechanic says he never touched then engine bolt? Even though I'm sure it's part of the 7500 mile service (Ducati service guy said he's the top mechanic) I've now torqued it to 40nm (r&g setting).
What if the mechanic says he never touched then engine bolt? Even though I'm sure it's part of the 7500 mile service (Ducati service guy said he's the top mechanic) I've now torqued it to 40nm (r&g setting).
As you say, it is a part of the 7.5k service. Check the attachment - the snap comes from the owner's manual. And I am pretty sure that the mechanic will say he did it right
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