24 Newton Metres of Torque - I'm not that brave ;) - Singletrack World Magazine March 26, 2017

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This topic has 35 replies, 21 voices, and was last updated 7 years ago by LeeW.

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24 Newton Metres of Torque – I'm not that brave ;)
Alex
Full Member

So the excellent instruction manual IBIS provide tells me the ‘new’ torque setting for the two main pivot axles (i.e. the ones that connect the front triangle to the swingarm) are 24NM. That’s as high as my torque wrench goes.

I think the only higher one I’ve ever seen for an MTB is some SRAM GX crank nonsense which is something unobtainable by a normal human. Even 24NM feels like it’s going to need a gibbon swinging on three foot of tubular bar welded to the socket.

It was still tightening and not clicking but I bottled out. I think I’ll take it to the shop and let a proper adult have a go. I reckon my personal limit is about 15NM before my brain screams ‘snap’ or ’rounded’. I assume everyone else on here doesn’t have similar hang ups and fully expect to be told to MTFU and get on with it.

Well I’m not. I’m going to read the rest of the instruction book which has many exciting pictures showing cable routing. I feel a lot more comfortable with that!

Posted 7 years ago

timber
Full Member

Is that left hand tight or right hand tight?

Posted 7 years ago

Alex
Full Member

Which is the one you do with a hammer? 😉

Posted 7 years ago

simondbarnes
Full Member

Even 24NM feels like it’s going to need a gibbon swinging on three foot of tubular bar welded to the socket.

It’s only a couple of bags of sugar on the end of a 3ft bar. You need to MTFU.

Posted 7 years ago

bencooper
Free Member

Pfft, some things I fit need a torque of 140Nm 😀

Posted 7 years ago

Alex
Full Member

Are they aircraft parts Ben? 🙂

I’ll go back in the shed Simon but if it goes wrong, I’m blaming you!

Posted 7 years ago

trail_rat
Free Member

I torque stuff in the region of 40000ft lbs it’s a little more an a couple bags of sugar .

When i over torque it doesn’t round out -it bursts open

Hubs nuts on cars are often 300ftlbs

I suspect you feel like your putting lots of effort as if your torque wrench is Maxing at 24 then it’s lever is short.

Posted 7 years ago

Oggles
Free Member

If you have got an average weight male adult gibbon lying around though, simply hang it on a 1’5″ bar.

Posted 7 years ago

Alex
Full Member

I have a 17 year old with those dimensions. It would involve me surgically removing him from his computer tho 😉 @trail-rat I bought that wrench as I wanted lots of granularity in the low numbers where most of the MTB stuff is. I don’t feel I’m leaning on it that hard but I have some history of mechanical savagery which suggest bad things might happen even if I’m following the instructions

And ‘burst open’ sounds lie one of those things 😉

Posted 7 years ago

Northwind
Full Member

24nm really isn’t much at all. If you get an XTR M970 crank it’s 45-55nm.

Posted 7 years ago

bramblesummer
Free Member

It might be that you’re bottling out because your torque wrench isn’t clicking off at the real torque value. The wrench could be faulty or out of calibration, so you could be applying a lot more than 24Nm. If there is doubt, then dont use the torque wrench. There is very good reason that a reference device is next to most company’s torque wrenches alongside regular calibration.

On another note, my ibis is happily setup with that figure. Just ensure the threads are clear of any crap or old loctite and you’re good to go.

Posted 7 years ago

singlespeedstu
Full Member

I’ve seen 4mm stem bolts that have been torqued higher than 24Nm when folks have asked me to look at their bikes. 😆

Posted 7 years ago

Alex
Full Member

Yes I know logically it’s not that much but physically I get flashbacks of ‘expensive stuff I’ve ruined’ even when doing my best not to be a mechanical klutz. You know how some people have feel’ and know when something is tightened correctly?

I don’t have that at all. What I have is the feeling of misery that yet again a simple procedure that everyone else can do has left me with a pantheon of broken parts. One thing I’ve learned is leaving it a day isn’t going to make it any worse. I think it was TJ that says ‘have a cup of tea and think about it’ whereas I’m more ‘have a beer and forget about it’

Posted 7 years ago

Alex
Full Member

@SSTU – did you ever fix one of mine 😉

@bramble – sensible advice. I’m gong to slacken everything off and have a proper look and make sure it’s clean before any more leaning on the spanner.

Posted 7 years ago

singlespeedstu
Full Member

Alex.
You must be tighten it until it strips then back it off one man. 🙂
At least you’re learning. 😀

Posted 7 years ago

bramblesummer
Free Member

Have a few ‘test clicks’ with a bolt in a vice or something that’s much bigger. It’ll give you a chance to practice and get some feel for your wrench. It might also show up an issue if it doesn’t click off at all. 24Nm really isn’t a lot, and as already mentioned, some much smaller fasteners like stem bolts get routinely overtightened.

Posted 7 years ago

maxtorque
Full Member

Back in the day, working at a 4wd specalist, we would ‘Torque up’the hub nuts on Scammel Explorers using a 4″ box socket, a 10foot length of scafolding, and an Landrover! (A series LR bumper was exactly the right height, to be driven into the socket and hold it in place whilst 3 or four of us jumped up and down on the end of the scaf-pole. When the socket split, it was tight enough……..

For our younger readers, an Explorer looks like this:

Posted 7 years ago

trail_rat
Free Member

And that’s why we have torque multipliers these days 🙂

Posted 7 years ago

Alex
Full Member

@bramble – another good idea for me to try

@maxtorque – that’s my kind iof engineering solution

Posted 7 years ago

br
Free Member

My SRAM/Spesh cranks are 34-41NM, I usually put the none d/s crank in the vice (laying the bike horizontal) and then use my big torque wrench to do up.

Taking off is the reverse except I have to use steel extension off my carjack and insert it over a breaker bar.

Posted 7 years ago

singlespeedstu
Full Member

My SRAM/Spesh cranks are 34-41NM, I usually put the none d/s crank in the vice

Really? I’m struggling to see why.
If you have trouble generating that kind of torque between your arms how do you manage to ride a bike offroad…

Posted 7 years ago

angeldust
Free Member

Swoons

Posted 7 years ago

singlespeedstu
Full Member

Swooning at 34Nm?
Really.
Do you have to ask your mom to open a bag of crisps for you. 😉

Posted 7 years ago

slowster
Free Member

That’s as high as my torque wrench goes.

I think that torque wrenches are supposed to be less accurate at the ends of their scale, and it’s better to use a torque wrench which has a range with the median close to what is required most of the time. For cyclists this is usually more of a problem at the bottom of the scale, e.g. using a torque wrench with a 5Nm-20Nm range to tighten allen bolts to 5Nm.

Even if your wrench is adequately accurate at the top end of the range, the wrench itself is likely to have a shorter handle than one with a higher range and for which 24Nm is nearer the middle of the range. That shorter handle equals less leverage and using it at the top of the range is going to feel much more extreme than using a longer torque wrench at the same torque setting. However, a longer handle/higher range may also mean a 3/8″ torque wrench, instead of 1/4″, so you might need new bits and also a new ratchet handle/breaker bar to undo the bolts, since the torque wrench itself should not be used for that.

Posted 7 years ago

thisisnotaspoon
Free Member

The problem is usually that bike stands don’t hold bikes when applying anywhere near that, so it becomes a two person job, one holding the bike/cranks and the other with the torque wrench.

Swoons

~10kg on a 12″ ratchet handle?

Posted 7 years ago

Alex
Full Member

Stuck a nut in the vice, got a feel for it, whacked it on the linkage having backed it off a bit, job done. They were pretty close so it’s good to know what that feels like. I’ll go do the rest of them tomorrow (which are at far lower NM) now I’ve got the measure of the wrench… ta all.

Posted 7 years ago

tjagain
Full Member

I am in the “its not that tight” school of thought

I only use a torque wrench on really critical parts, the only time I have used on on a bicycle is on my ebike kit which has huge warnings about the bb nut which MUST be in the 55-60 NM range – any less it will loosen, any more splits the casting

How big is the bolt in question?

Posted 7 years ago

bencooper
Free Member

Are they aircraft parts Ben?

Schlumpf drive 😉

Posted 7 years ago

trail_rat
Free Member

The problem is usually that bike stands don’t hold bikes when applying anywhere near that

not all bike stands are from aldi.

Posted 7 years ago

padkinson
Free Member

The bolt that holds my bike rack to the towball is supposed to be done up to 90Nm. I just jumped on the end of the wrench.

Posted 7 years ago

bennyball
Free Member

I think that torque wrenches are supposed to be less accurate at the ends of their scale, and it’s better to use a torque wrench which has a range with the median close to what is required most of the time.

Agree with this, I’ve acquired a set of torque wrenches for this purpose. Saying that 24Nm is a bit of an odd number as a lot are 1-20Nm or 20Nm+, neither are ideal.

Posted 7 years ago

oink1
Free Member

Alex – Member
It was still tightening and not clicking but I bottled out. I think I’ll take it to the shop and let a proper adult have a go.

It specifies that torque. If you’re confident you didn’t buy a POS wrench then go for it. 24Nm is no biggie 🙂

Posted 7 years ago

hols2
Free Member

From memory, old style crank bolts need 40 Nm or so. Cylinder head bolts for cars are generally double that, so a decent 1/2″ drive torque wrench handles that easily.

Posted 7 years ago

aracer
Free Member

That’s about right, old style screw fit BBs a bit higher. 24Nm isn’t anything special at all – but then I have two torque wrenches, the standard Draper one from Halfords starts at 20Nm IIRC.

Or you could 😯 just sit the bike on its wheels and lean it against your leg, just because you have a stand doesn’t mean you have to use it for everything. One hand on the torque wrench, one on the crank. I’ve done loads of cranks and BBs that way (probably more than most apart from pro mechanics as I have beasts on which I’m often swapping cranks).

Posted 7 years ago

Alex
Full Member

I turned it upside down as I needed an an allen key on the other end as well. It’s an axle that passes through the frame and is tightened by the other end being threaded. In between axle and frame and the bearings.

How big is the bolt in question?

6mm

Posted 7 years ago

LeeW
Full Member

I think that torque wrenches are supposed to be less accurate at the ends of their scale, and it’s better to use a torque wrench which has a range with the median close to what is required most of the time. For cyclists this is usually more of a problem at the bottom of the scale, e.g. using a torque wrench with a 5Nm-20Nm range to tighten allen bolts to 5Nm.

If it’s manufactured to the British Std then all wrenches are calibrated with a tolerance ‘of reading’ (generally 4%) the higher the value of torque (within its range) the higher the tolerance. Drivers are even less accurate at 6% of reading.

more and more wrenches are coming out with manufacturer’s tolerances which are generally better than the BS std – makes them stand out in the market.

Posted 7 years ago