# how the heck much is 5Nm?



## BendBiker

Hey-

My stem says that I should tighten it down to 5Nm, and I know that over tightening carbon steerer tube can be dangerous. Can anyone tell me roughly how tight this is? (ie like really tight, less than you think etc...) Please don't tell me to buy a torque wrench as I have not the funds nor the time

Thanks


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## Keeping up with Junior

*Park Tool Chart*



BendBiker said:


> ...Can anyone tell me roughly how tight this is?...
> ...Please don't tell me to buy a torque wrench as I have not the funds nor the time...


Go to the torque wrench section of Park Tool and find other bike components on the chart with similar torque specificaitons. That may give you a general idea of how much torque to use. Scroll to the bottom for a table converting Nm to in-lb.

http://www.parktool.com/repair/readhowto.asp?id=88


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## tlite48

5nM is approximately 45 in/lbs (inch pounds) or 3 ft/lb (foot pounds). VERY LITTLE TORQUE!


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## C-40

*common sense...*

Use a short handled hex wrench or a 4-5-6mm Y-style wrench and don't get carried away. A moderate twist of the wrist will do the job. If the bars rotate on the first significant bump you hit, then they're not tight enough. Personally. I've never used a torque wrench. You can't take one with you on a ride.


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## BendBiker

k thanks guys


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## capt_phun

5 Nm is the amount the Ritchey Torque Key is set at just for this purpose. For $20 it is a small piece of insurance that is great.


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## Howzitbroke

two yard tons.


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## Keeping up with Junior

*Slide Rule*



Howzitbroke said:


> two yard tons.


Can you provide the formula for that so I can make other coversions to the elusive *Y.T.* torque measurements using my slide rule and six foot long allen wrench.


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## Howzitbroke

I am unsure of any slide rule conversion, but using a hexidecimal vertical abacus with force vector analysis you should be able to get the numbers you need. Refer to the Barnett's manual page 2,483. I recommend using the Campy abacus if you can find it. Many of them out there are older but the Campy model stays acurate because like most of their tools it was way overbuilt and can be used to apply peanut butter to bread. One final note yard tons will not work on most threading. Left hand BSA is generally thought to be most compatible.


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## teoteoteo

BendBiker said:


> Hey-
> 
> My stem says that I should tighten it down to 5Nm, and I know that over tightening carbon steerer tube can be dangerous. Can anyone tell me roughly how tight this is? (ie like really tight, less than you think etc...) Please don't tell me to buy a torque wrench as I have not the funds nor the time
> 
> Thanks



At 6nm you'll hear a crack, back it off a half turn from there......

On a serious note if the stem is a two bolt system make sure the top bolt does not sit higher than the top of the steerer. I can't tell you how many carbon steerers I've seen get mangled this way.


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## Tlaloc

*Can't Afford a Torque Wrench?*

You say your bike has a carbon steering tube so you would have to have spent a whole lot of money to buy it. You say you don't have the time or money to get a torque wrench. On a carbon bike you should never tighten any bolt without one. Yeah, I know, the posters on this forum are such great mechanics that they can tighten a bolt to spec using their hands. But us mortals can't. In my opinion you can't afford not to have one.


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## MikeBiker

Get a torque wrench. Here is one for $11.


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## Keeping up with Junior

*Ebay Search*



Howzitbroke said:


> ...I recommend using the Campy abacus if you can find it...


Still looking for a genuine Campy abacus. Ebay only had one listed and it was a 50th anniversary edition that I could not afford. The only abacus I could get my hands on locally was borrowing one from a buddy that uses it to dial in his ice fishing equipment (you know, that _other_ brand). Trouble is that since he got it at his LFS instead of the LBS it is calibrated for League/Ounce *L.O.* torque which I guess is what he uses when tieing flies. I really wish the two companies could agree on a standard so they would be interchangable. At least they have both agreed on the ten speed abacus for now so I just need to hook the cable up on the wrong side to index the movement of the beads.


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## Howzitbroke

I went back up to the top of this post and started thinking. You know my responses have been muddled. I think if the OP just clamped the appropriate sized allen wrench for his stem in a bench vise and then hoisted the entire bike up there with the bolt engaged to the allen he could then use the frame for leverage to get the bolt properly torqued.


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## 99trek5200

BendBiker said:


> Hey-
> 
> ...Please don't tell me to buy a torque wrench as I have not the funds nor the time
> 
> Thanks


To save time, you could try Googling the question. Looking at the thread history it took you about an hour and a half to get a response. It took less that 30 seconds to find this http://www.katonet.com/Techinfo/conversion.htm

Just a thought.


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## Mark McM

*Conversions*



Howzitbroke said:


> two yard tons.



1 Nm = 1 Joule

1 Joule = 1 Watt*Second

Therefore,

5 Nm = 5 Watt*Seconds


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## JCavilia

*On this scale,*

it's just a little beyond "kinda tight", but well short of "pretty tight".


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## Howzitbroke

Nice scale. Just curious though, how the hell do you get thumb tight? I only have a thumb on each hand. When tightening the finger is the limiting digit since it is weaker. I don't see how I could achieve thumb tightness when the finger always clicks first. I would assume you need a two thumbed hand or a thumbed tool extension device. Right?

It is also missing gorilla tight, hamfisted clown adjusted, and hillbilly impact wrench snug. My wrench must be more acurate.


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## Howzitbroke

How many micron AMU's is that?


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## G60

get a torque wrench. they're cheeeeeap!


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## Entropy906

I got one of these for my Ritchey bars and stem. http://www.excelsports.com/new.asp?page=8&major=6&minor=6&description=Torqkey+4mm+head+5Nm&vendorCode=RITCHEY


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## Al1943

Besides getting the torque right it's important to bring the torque up gradually alternating between pinch bolts, assuming you have two bolts. Go easy!

Al


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## drewmcg

*don't get a 1/2" drive torque wrench for this application*



Tlaloc said:


> You say your bike has a carbon steering tube so you would have to have spent a whole lot of money to buy it. You say you don't have the time or money to get a torque wrench. On a carbon bike you should never tighten any bolt without one. Yeah, I know, the posters on this forum are such great mechanics that they can tighten a bolt to spec using their hands. But us mortals can't. In my opinion you can't afford not to have one.


For that small a bolt/light a torque, you'd be better served by a 3/8" -- or even 1/4" -- torque wrench. The 1/4" would probably give you better accuracy for the stem, but not enough toque for a bottom bracket (in case you ever feel compelled to torque one of those). The 3/8" could likely handle both.

If you go with the "click" style torque wrench, be sure to get one that calibrates down to at least 40 inch/pounds, e.g.: http://www.amazon.com/Pro-Quality-2...70-9237539?ie=UTF8&s=hi&qid=1172955824&sr=1-5 (1/4").

Here's a torsional torque wrench with both 3/8" and 1/2" heads for $10: http://www.bostonindustrial.com/22towr.html .


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## Ken

Entropy906 said:


> I got one of these for my Ritchey bars and stem. http://www.excelsports.com/new.asp?page=8&major=6&minor=6&description=Torqkey+4mm+head+5Nm&vendorCode=RITCHEY


Got one too. Seems idiot proof.


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## brblue

*...*

5Nm is a 5N force applied perpendiculary to a 1m handle.
This said, if you've got a wrench with a 1 m long handle you fix it to the nut, so that the wrench is horizontal. Put a weight of 0.5 kg on the end of the wrench and you'll tighten the nut with 5Nm.

Formula is 

M=Force * lever_length (force is applied at 90deg to the lever)
M=Mass * acceleration * lever_length

acceleration is about 10m/(s*s), if you use a weight that presses down onto the wrench handle(no supplementary force applied by you). 
mass in kg
lever_length in m
M is the torque, in our case 5Nm

You can do the math for whatever lever length your wrench provides.

good luck
br


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## Eric_H

*Count the turns*



C-40 said:


> Use a short handled hex wrench or a 4-5-6mm Y-style wrench and don't get carried away. A moderate twist of the wrist will do the job. If the bars rotate on the first significant bump you hit, then they're not tight enough. Personally. I've never used a torque wrench. You can't take one with you on a ride.


I agree with C-40, when it comes to seat tube clamps and stem clamps it is important to be able to make adjustments while out on the road. However, with the relative fragility of some components, using a torque wrench is still a good idea even for a seasoned mechanic. And for the OP, if you torque your stem down with a torque wrench at home and then have to make an adjustment on the road, just count the number of turns or 1/2 turns you loosen the bolts off, and then tighten them the same amount. Pretty easy way to get the same torque.

I just ordered a low-torque torque wrench and I plan to use it in situations where I have never used one before, such as clamp-on front derailleur to carbon frame. And I have a larger torque wrench for the high torque applications. 70 N-m (51 ft-lbs) on a Campy BB cup is a lot of torque, even 38 N-m (28 ft-lbs) on a Campy square taper crank is quite a bit. I always prefer to ensure that these items are tightened properly.


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