Stem to steerer 6-8 nm im not so sure !?

buder
buder Posts: 154
edited March 2011 in Workshop
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 ?

Thanks

Comments

  • sungod
    sungod Posts: 17,427
    5nm is probably enough, torque ratings are usually maximums, not what you actually need

    if it isn't slipping then it's tight enough, so if 4 is enough, stop at 4

    estimating torque by 'feel' is notoriously innacurate

    the park tool is probably right, it's hard to go wrong with a beam-type wrench
    my bike - faster than god's and twice as shiny
  • buder
    buder Posts: 154
    Thanks for that, it was a bit of a shock at first at just how tight 5nm was.

    Ill leave it at that being as that's the lower end of the range they specify although its still tighter than what I would have done by feel.

    could I have done any damage constantly loosening and tightening whilst messing around ?
  • sungod
    sungod Posts: 17,427
    buder wrote:
    Thanks for that, it was a bit of a shock at first at just how tight 5nm was.

    Ill leave it at that being as that's the lower end of the range they specify although its still tighter than what I would have done by feel.

    could I have done any damage constantly loosening and tightening whilst messing around ?

    probably be ok unless you went way way over - usually there's a compression plug inside the carbon steerer, it depends on brand/steerer but generally the plug extends the full length of the clamp area, so i think it makes crush damage from overtorquing the clamp less likely
    my bike - faster than god's and twice as shiny
  • Yossie
    Yossie Posts: 2,600
    could I have done any damage constantly loosening and tightening whilst messing around

    So long as you haven't crossed any threads or done anything massively cack handed, and its now all nicely greased up, then no.
  • rake
    rake Posts: 3,204
    if its not slipping and your feel says its nipped up well id go with that, i do anyway. not had any trouble. 4Nm is pleanty imo.
  • buder
    buder Posts: 154
    Yossie wrote:
    could I have done any damage constantly loosening and tightening whilst messing around

    So long as you haven't crossed any threads or done anything massively cack handed, and its now all nicely greased up, then no.

    I have not gone tighter in my fettling than 6nm and it was mainly me trying to get a feel for the torque values so was loosening and tightening it gently trying the new wrench etc.

    Ive left it at 4.5 as to me thats tight enough its not slipping so will leave it at that I think.

    id love to know anyone that has wrenched upto 8Nm like whats published on Planet X that seems loads tighter than it need be ?
  • rake
    rake Posts: 3,204
    its worth knowing although its probably down to the type of wrench some wrenches can be damaged or uncalibrated whilst being used to undo things. things might have moved on but it used to be the case.
  • on-yer-bike
    on-yer-bike Posts: 2,974
    I have a Park beam wrench TW-1, the small one. I tighten everything to 30 inch pounds except the stem cap bolt. Doesn't have NMs on the scale but I think its 3.4 nm. I also use carbon assembly paste. Use the same torque on the seat post. I have cracked a carbon fork steerer tightening to some recommended torque that was way too high, so be careful. I learnt the hard way.
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