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Swingarm locknut torque?

Posted: Sun Jul 06, 2008 6:36 pm
by fastdruid
I've just come to tighten up the locknut for the swingarm on the RVF and the HBOL states that the Honda special tool has to be used as the torque setting is adjusted for the offset. Except the tool I have is just a socket type one.

So either
A) What is the actual torque setting of the locknut (ie unadjusted for the special tool).
B) What is the offset[1] (ie the distance inbetween the centres of the two holes) on the honda tool?

Druid

[1] I can unadjust the figure it if I know this. :D

Re: Swingarm locknut torque?

Posted: Sun Jul 06, 2008 9:52 pm
by TonyB
The offset on the Honda tool is 49.5mm.
So unless you want to be pedantic, 2" or 50mm will do.

Tony

Re: Swingarm locknut torque?

Posted: Sun Jul 06, 2008 10:20 pm
by Speedy
IIrc I've tightened mine without the Honda tool, to just over the specified torque; that was some 3 years ago and touch wood it's still tightened! :|

Re: Swingarm locknut torque?

Posted: Sun Jul 06, 2008 11:48 pm
by fastdruid
Thanks, tbh not that it really matters as my torque wrench probably has a greater margin of error than the difference anyway. :D

Druid

Re: Swingarm locknut torque?

Posted: Mon Jul 07, 2008 1:48 am
by RVFJE
I've been looking for this info for years. Too scared to remove the swingarm because Mr Haynes says you cannot properly torque the nuts without the special Honda tool and I don't have one.
I had a socket made up to just fit on the torque wrench but didn't want to use it.
"Just over the specified torque" - how much is that?
Does the special tool apply more or less torque thatn just using a modified socket ?

Re: Swingarm locknut torque?

Posted: Mon Jul 07, 2008 7:41 pm
by fastdruid
Well its 65Nm[1] with the special tool.

65Nm is the same as a 65N force acting on a 1m length, if you offset that length by 5cm your 65N is now working on a 1.05m length. Now remembering your GCSE maths about moments and 65Nm at 1.05m is the same as 68.25 at 1m (65*1.05)/1

So if using a special tool that acts in the centre of the nut the torque should be 68.25Nm. Not that you're likely to get within 3Nm of the correct figure anyway as torque wrenches are around 5% inaccurate.

Druid

[1] For the RVF, 80Nm for the VFR according to the HBOL.

Re: Swingarm locknut torque?

Posted: Mon Jul 07, 2008 9:23 pm
by Speedy
RVFJE wrote: "Just over the specified torque" - how much is that?
Just a bit before it snaps! ;)
I've set the torque wrench to the specified torque, tighten it to that, then added a bit more... fastdruid's exlanation seems about right, so 70Nm is about what I went for. I went on the principle that there are slight tolerances and that I'd rather have it on the tighter side rather than loose, so if it was going to break, I'd rather it did so when I was tightening it there and then, instead of when I was out on it at speed! :)

Re: Swingarm locknut torque?

Posted: Mon Jul 07, 2008 9:33 pm
by fastdruid
Speedy wrote:
RVFJE wrote: "Just over the specified torque" - how much is that?
Just a bit before it snaps! ;)
I've set the torque wrench to the specified torque, tighten it to that, then added a bit more... fastdruid's exlanation seems about right, so 70Nm is about what I went for.
Well I think I'm right.... :D
I went on the principle that there are slight tolerances
More than slight, there will be a given minimum clamping force that will be aimed for then everything will be taken into account (torque wrench inaccuracy, thread locking or lubricating compounds, material strength etc) and the torque wrench figure will be the minimum guarantied to hit that clamping force while not exceeding the material strength.

This is also why you have to be careful about using lubes where they aren't meant to be used as it's very easy to over torque (and snap) a bolt if the friction is too low or under tighten if the bolt originally used some liquid thread lock (and you didn't).

Druid

Re: Swingarm locknut torque?

Posted: Tue Jul 08, 2008 12:12 pm
by RVFJE
65-70nm is it then. Thanks guys. I'll take the s/arm off now and check and grease the bearings knowing I can torque it back on.