What do you think are the units of torque ?

[DeuxCentCinq]

I've been reading a few topics on here and have noticed that people disagree on the principles of torque.  More specifically, how it's calculated and therefore how to express the units.

[sKrEwBaLL]

Christ, we're not still banging on about this are we..?!

[DeuxCentCinq]

I thought that the confusing *ahem* discussions the other day might have left some people unclear as to the correct definition.  

I was hoping that this would be a way to help everyone to understand.

[kniterider]

thats a very french sounding name youve got..............................................?

[Overseer]

* Overseer can smell garlic

[DeuxCentCinq]

thats a very french sounding name youve got..............................................?

Yes, it is.  However, I don't see why that should have any bearing on this topic...

[sKrEwBaLL]

Judging by the number of votes so far, it seems that no-one really give a sh!t

[DeuxCentCinq]

Judging by the number of votes so far, it seems that no-one really give a sh!t

Thanks for your constructive comment, I'm sure that it's really helped people to understand things more clearly.

Since when discussing cars (whether they be French OR German) the topic of torque will probably figure in the conversation somewhere it would be nice if everyone knew the correct definition.  

Some of the people on here really have no clue and I would imagine that their incorrect definitions will unfortunately be picked up by newbies and thus the ignorance is spread.

I would hope that one of the aims of this forum is to provide an accurate source of information for Golf GTi owners.  It is in the interest of every forum member to check other peoples information and correct them where necessary - I was just trying to get the ball rolling.

Yes, perhaps a poll was not the best way of raising this point, just thought it might highlight a fundamental gap in the knowledge of a couple of rather arrogant people, and thus teach newbies hoping to learn something, who and who not, to listen to.  It might have the added bonus of teaching the arrogant ones to keep their opinions to themselves unless they are positive that they are not giving misleading information.

I expect that this post will probably receive some abuse, after all I drive French cars...

[sKrEwBaLL]

OK mate calm down its only a bit of banter.  My point is that it doesnt really matter whether its lbs per foot or lbs X foot or whatever.  Nobody is going to hear a figure and picture a square foot and imagine x lbs on top of it or whatever and think...  "wow thats a lot of torque", all they know is relative figures one versus the other, knowing that a higher number is better, so ppl dont really need to know the exact definition unless theyre sitting a physics A level or something.

[DeuxCentCinq]

If people only cared about that figures rather than the units, then why did I see so many posts where people argued that their definition was the correct one ?!

I would say that it does matter, for example:

If a wheel bolt is particularly difficult to undo, i.e. it's very tight.  You would need to increase to torque that you're applying in order to undo it.

If we say that the force you can supply is constant i.e. you always apply the same force using your muscles or body weight etc.  Then how do you increase the torque ?

If we assume this definition of torque :

Torque = Force/Distance

Then this suggests that to increase torque you need to DECREASE the distance.  
This is clearly INCORRECT as we all should know that using a longer bar will help us undo the wheel.

Everyone knows that a longer bar (greater distance) will help us to undo the stubborn bolt, but it appears that not everyone knows that what is actually happening when you do this is that the torque is increased.

The CORRECT definition is :

Torque = Force * Distance

From this formula you can see that to increase torque you can increase either the force or the distance or both.

The SI units are :

Force is measured in Newtons (N)
Distance is measured in metres (m)

Therefore the units of torque are :

Newton Metres or Nm if you prefer.

In the UK we still sometimes use imperial units, in this case Pounds (lb) and Feet (ft), so you might see the units of torque written like this :

lbft

For goodness sake, if anyone wants proof you'll probably find it's written on your torque wrench !  (I take it everyone know's what one of those is)

The units are NEVER, EVER any of these:
N/m
Newtons per metre
Nm^-1
lb/ft
Pounds per foot
lbft¹

If you see any of them used then the person that wrote it is wrong.

Here's the correct description:

The torque generated about an axis is defined as the product of the component of the force perpendicular to the axis and the perpendicular distance between the line of action of the force and the axis.

(For those that didn't understand it the first time, "product" means multiplied by)

Perhaps I should have put this post up to start with, I just hoped that the first time I provided the description coupled with this poll some people might have put 2 and 2 together !