Only 5Nm on a stem/handlebar clamp?

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Cyril Haearn
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Cyril Haearn » 15 Nov 2019, 1:14pm

Plusminus, I do not have a modern light cycle :wink:
I often think team mechanics are to be admired, they fix complicated machines without riding them. I need a lot of time, check, test-ride before I am sure my machine is right
Nice one Cyrille, nice one son..
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Marcus Aurelius
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Marcus Aurelius » 15 Nov 2019, 1:14pm

You’d be surprised how tight 5Nm is. It’s what most of the bolts for my carbon bike bits require. Use a torque tool, doing it by hand is surprisingly inaccurate. The torque tool doesn’t have to be super accurate, a pre set torque tool like this

https://www.evanscycles.com/fwe-5nm-tor ... h-EV183166

Would be fine.

Samuel D
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Samuel D » 15 Nov 2019, 1:26pm

Marcus Aurelius wrote:You’d be surprised how tight 5Nm is.

You say that, but when I got a torque wrench I was surprised how light 5 Nm is. I was going far tighter than that with finger and thumb on an Allen key.

Pwa had a similar experience:
pwa wrote:5Nm isn't much and doing it with an allen key is risky. I broke a stem where it clamps on the steerer by overdoing it and I was trying to be moderate.

And yet Manc33 agrees with you:
Manc33 wrote:When I got a 5Nm torque key I realised 5Nm was more than I thought.

Which just goes to show that it’s all guesswork until you get a torque wrench.

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Mick F
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Mick F » 15 Nov 2019, 1:33pm

I never really understand this metric stuff. :lol:

5Nm= 3.687811ft-lb

Foot Pounds, I do understand.
3.7ftlbs is hardly anything.
I would be very worried indeed if my handlebars were held on by only 3.7ftlbs.

I have a torque wrench but it has a half-inch square drive on it. I don't have the adaptors to connect up a 4mm Allen key .......... and even if I had, I doubt it would go down as low as 3.7ftlbs.
Mick F. Cornwall

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Mick F
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Mick F » 15 Nov 2019, 2:12pm

PS:
I'm willing to bet that if I put the four bolts on my Ahead stem to 5Nm, I would be able to twist my handlebars.

I could buy one of these to prove it.
https://www.evanscycles.com/fwe-5nm-tor ... h-EV183166


.................. then return it as an unwanted item. :wink:
Mick F. Cornwall

Brucey
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Brucey » 15 Nov 2019, 2:25pm

Cyril Haearn wrote:Torque wrenches may be faulty, can one easily get them calibrated?
Feeling by hand is quite accurate I think


did you mean

Cyril Haearn wrote:Torque wrenches may be faulty, one can easily get them calibrated.
Feeling by hand is quite inaccurate I think


cheers
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mattheus
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Re: Only 5Nm on a stem/handlebar clamp?

Postby mattheus » 15 Nov 2019, 2:27pm

Samuel D wrote:Pwa had a similar experience:
pwa wrote:5Nm isn't much and doing it with an allen key is risky. I broke a stem where it clamps on the steerer by overdoing it and I was trying to be moderate.

And yet Manc33 agrees with you:
Manc33 wrote:When I got a 5Nm torque key I realised 5Nm was more than I thought.

Which just goes to show that it’s all guesswork until you get a torque wrench.


It's not guesswork - you just have to know who to ask.

Cyril Haearn
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Cyril Haearn » 15 Nov 2019, 2:33pm

Brucey wrote:
Cyril Haearn wrote:Torque wrenches may be faulty, can one easily get them calibrated?
Feeling by hand is quite accurate I think


did you mean

Cyril Haearn wrote:Torque wrenches may be faulty, one can easily get them calibrated.
Feeling by hand is quite inaccurate I think


cheers

Not sure, I think not, I am a bit confused :?
Who calibrates the calibrators? Read somewhere a while ago about inconsistent results

Fitted a new bottle cage, small allen bolts, small allen key, no torque wrench. When the key nearly started to bend I guessed the bolts were tight enough
Apart from torque, re-checking the bolts after the first ride is very advisable, right?
Nice one Cyrille, nice one son..
Cycling-of course, but it is far better on 49" fixed
We love safety cameras, we love life "1330"

Darkman
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Darkman » 15 Nov 2019, 2:43pm

But if your bottle cage works loose, you're [probably] not going to end up going a&#% over elbow into a ditch.

If your handlebars fail, you're more than likely in a world of trouble.

Brucey
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Brucey » 15 Nov 2019, 3:11pm

Cyril Haearn wrote: Who calibrates the calibrators? Read somewhere a while ago about inconsistent results


it is not very difficult to check a torque wrench; you just need a lever and a weight. In critical application areas (eg aircraft maintenance) wrenches are checked almost before every use. For a variety of reasons torque wrenches are likely to be an imperfect means of tightening bolts, not least because the friction in the bolt/thread is likely to vary. It is still the best available way of setting fastener tension though.

Fitted a new bottle cage, small allen bolts, small allen key, no torque wrench. When the key nearly started to bend I guessed the bolts were tight enough
Apart from torque, re-checking the bolts after the first ride is very advisable, right?


It is a good thing that bottle cages are not a super-sensitive application... but yes, checking bolts have not loosened in the first few rides is never a bad idea. It counts many times over whenever you are bolting things down/through painted interfaces (which is most things on a bike frame....); paint films relax/creep and bolts that were tight to start with can soon loose their grip.

cheers
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Cyril Haearn
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Cyril Haearn » 15 Nov 2019, 3:15pm

Darkman wrote:But if your bottle cage works loose, you're [probably] not going to end up going a&#% over elbow into a ditch.

If your handlebars fail, you're more than likely in a world of trouble.

I have sturdier tools for wheelnuts, for example
Just made a note to check my bars before the next ride
Nice one Cyrille, nice one son..
Cycling-of course, but it is far better on 49" fixed
We love safety cameras, we love life "1330"

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Mick F
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Mick F » 15 Nov 2019, 3:56pm

Brucey wrote:it is not very difficult to check a torque wrench; you just need a lever and a weight.
I suppose the same thing can be done with an Allen key and a weight - or at least a spring balance.

4mm Allen key is what?
3" long?
Quarter of a foot?

3.7ft lbs x 4 = 14lbs+ pull on the end.

Thinking about it, a stone pulling on the end of the key seems quite a bit! :shock:
I could well be wrong about 5Nm not being tight enough!
Mick F. Cornwall

Manc33
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Re: Only 5Nm on a stem/handlebar clamp?

Postby Manc33 » 15 Nov 2019, 5:21pm

I calibrate my Cyclo torque wrench against my Ritchey 5Nm torque wrench. The Cyclo has a hex nut on the end I take off (with it still set at 5Nm) then you can independently rotate the screw thread that hex nut was on. After a lot of trial and error (screwing back down the actual end dial each time) checking it's clicking about where the Ritchey tightened it to, it's calibrated. That Cyclo scares me though, it feels stiff and I am almost certain it goes out of calibration very easily, like after 3 uses - unfortunately when it does that, it's tightening to more than it's set to, not less.
When two cyclists get married, they should throw anodized cable crimps instead of confetti.