stem to steerer torque confusion

[bad boy]

Hello all

I just got an SL Pro and have been messing with the stem to steerer torque.

I decided to get the park tools beam wrench as I like the idea of seeing the value as you wrench and lots have been said about the cheaper 'click' torque wrenches so I settled on this one.

Out of curiosity I tried estimating 5nm with a normal allen key and I was way under, I was stoping at around 3.8 before it felt tight enough IMO. Whats bothering me is that im not using the beam wrench properly, as when tightened to what it says is 5nm if I swap it for my allen key to try and get a feel for this value its far tighter than I would have gone to had I not had the wrench and planet x say 6-8 nm !! blimey is that right I think thats far to much ?.

Maybe im a bit too cautious being as its carbon steerer but if I had tightened it to much would I have heard it crack there and then or could it go later ?

Thanks

 

[Gerry Attrick]

You are experiencing what many novices do when using a torque wrench for the first time. It gives the lie to those who say they can accurately estimate torque merely by feel. After nearly forty years of wielding spanners at everything from bikes to marine engines, I would never say I could estimate torque by feel.

Put your faith in your torque wrench. Just make sure you are using the correct figure for the component.

 

[Smokin Joe]

5nm is far tighter than I've ever torqued up bolts on a steerer or seatpost, like you I was surprised at how tight 5nm was when I tried a torque wrench myself. In fact most carbon seatposts recommend 6nm, but the smaller bolt on modern frame clamps will strip it's threads at just over 5nm.

A torque wrench is totally un-necessary on a bike unless you are a ham fisted gorilla in the habit of using a two foot extension bar on the end of the Allen key. And it's about time the prats who write for cycling magazines stop trying to convince us that it is, either they are trying to push their advertisers products on us or most of them know F-all about bikes.

 

[Gerry Attrick]

5nm is far tighter than I've ever torqued up bolts on a steerer or seatpost, like you I was surprised at how tight 5nm was when I tried a torque wrench myself. In fact most carbon seatposts recommend 6nm, but the smaller bolt on modern frame clamps will strip it's threads at just over 5nm.

A torque wrench is totally un-necessary on a bike unless you are a ham fisted gorilla in the habit of using a two foot extension bar on the end of the Allen key. And it's about time the prats who write for cycling magazines stop trying to convince us that it is, either they are trying to push their advertisers products on us or most of them know F-all about bikes.

I bow to your superior knowledge/feel for torque SJ. I hope the newbies to cycling mechanics have half of your mechanical prowess.

 

[Smokin Joe]

I bow to your superior knowledge/feel for torque SJ. I hope the newbies to cycling mechanics have half of your mechanical prowess.

It's nothing to do with a feel for torque, but as I said (and the OP found himself) you will not do anything on a bike too tight unless you are a Charles Atlas clone devoid of all sensitivity. When tightening carbon components just do as you normally would and you will be well within the safety limits.

 

[bad boy]

Thanks for the replies in a way its somewhat reassuring as if you said 5nm is effortless with a normal allen key I would know im doing something wrong.

I can only trust with some common sense what the published torque values are. In this case I see no point in going tighter when not needed ive left it at 5nm. Id love to know if anyone has their stem tightened to 8nm on a carbon steerer and has survived to tell the tale ?.

It just makes me wonder what sort of tolerances manufacturers factor in when publishing these values I mean 5-8 is a far difference ! it worries me that im putting to much faith in what ive been told to do as opposed to what to me feels tight enough which in this case is far lower than the lowest value in the range published ??.

I think im confusing myself with all this

 

[Gerry Attrick]

The snags arise when for instance someone has a seat post which slips in a carbon frame. Merely tightening as much as you are able with a short allen key may easily damage the frame. (Use carbon assembly paste).

 

[bad boy]

The snags arise when for instance someone has a seat post which slips in a carbon frame. Merely tightening as much as you are able with a short allen key may easily damage the frame. (Use carbon assembly paste).

Yes thats true, now I have a torque wrench I will always use it but think I needed reassurance after the shock of establishing how tight things are supposed to be.

If I did go to tight would it have cracked there and then ? and could I have done damage by loosening and tightening the stem on the steerer over and over trying to check I had done it right ?

Thanks

 

[Gerry Attrick]

It is also important to tighten dual stem or pedal bolts evenly. Gradually nip up one bolt, then the other, then tighten number one a bit more, then back to number two and so on until they are equally tight. The torque wrench makes it easy to get both bolts evenly tight.

 

[bad boy]

Ill give that a go just wondering if I have done some damage in my fettling already !?.

 

[Gerry Attrick]

Highly unlikely as you have said you tightened the bolts by hand far less than the torque wrench indicated was correct.

 

[bad boy]

Highly unlikely as you have said you tightened the bolts by hand far less than the torque wrench indicated was correct.

true although I corrected them with the torque wrench to that of 5Nm which to me seemed really tight so its this im worried about in terms of doing damage. I cant see how as I say planet x state upto 8Nm for this part which made me think I was doing something wrong.

 

[Gerry Attrick]

I don't know what you want me to say Badboy. If you tightened the bolts to the correct torque as indicated by your torque wrench, they will be correct.

Look at it this way, if you were a pilot flying an aeroplane in 10/10 cloud and your charts indicated mountains in your area at 10000 feet, but your altimeter said you were flying at 15000 feet, would you fly 5000 feet lower because your instincts told you to?

 

[bad boy]

Good point