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Carbon paste

andyh01andyh01 Posts: 571
edited May 2019 in Workshop
Hi all
I'm tempted to make a small rotational adjustment to the handlebars, the stem is alloy 4 bolt face plate but the bars are carbon. When the bike arrived there was I assume wet carbon paste, now the bars have been tightened the paste has dried.
If I were to adjust the bar position, would I need to use some carbon paste and if so , do I need to clean the old stuff off?
Or can I just losen bolt's off adjust bars and retighten bars without using paste?
Thanks

Posts

  • andyh01andyh01 Posts: 571
    Hi all
    I'm tempted to make a small rotational adjustment to the handlebars, the stem is alloy 4 bolt face plate but the bars are carbon. When the bike arrived there was I assume wet carbon paste, now the bars have been tightened the paste has dried.
    If I were to adjust the bar position, would I need to use some carbon paste and if so , do I need to clean the old stuff off?
    Or can I just losen bolt's off adjust bars and retighten bars without using paste?
    Thanks
  • whyamiherewhyamihere Posts: 7,398
    Just loosen and adjust, the bits of the paste which keep things in place will still be there. Many bars are textured in that area so that you don't even need paste. When putting it back together, it's best to use a torque wrench to finish off the face plate to make sure you don't overtighten it, because there's a risk of crushing the bar if you do tighten the bolts too much. Start at 3-4 Nm and see how low you can keep the torque without the bar moving.
  • andyh01andyh01 Posts: 571
    Thanks. Yes worried about torque, I might pick up the X tool essential at £25, the bars I have say 7nm
  • lesfirthlesfirth Posts: 1,104
    When you hit a pothole with your weight on the shifter hoods the force twisting your handlebars will far exceed anything you apply when you are trying to tighten the stem bolts as advocated above. Your bars are made of carbon fibre not wet tissue paper. It is the stuff they make F1 car chassis from.It really is strong stuff. If you are used to tightening bolts on a bike just tighten them. If not, use a torque wrench. I have not tried it but I would not be surprised if you broke the bolts before you crushed the bars.
  • whyamiherewhyamihere Posts: 7,398
    lesfirth wrote:
    When you hit a pothole with your weight on the shifter hoods the force twisting your handlebars will far exceed anything you apply when you are trying to tighten the stem bolts as advocated above. Your bars are made of carbon fibre not wet tissue paper. It is the stuff they make F1 car chassis from.It really is strong stuff. If you are used to tightening bolts on a bike just tighten them. If not, use a torque wrench. I have not tried it but I would not be surprised if you broke the bolts before you crushed the bars.
    There's lots of examples online of bars crushed by too much torque on the stem bolts. I've actually done it myself (fortunately on relatively cheap bars). Carbon fibre is very strong, but it's not magic. These things have torque specs for a reason.
  • sungodsungod Posts: 13,205
    op - leave the paste in place

    if you need only to adjust, loosen the top pair of bolts half a turn each to loosen, repeat until you can rotate the bars, reverse the process to tighten

    but if you've removed/significantly loosened the faceplate, when tightening you should ensure you do it evenly, otherwise it's possible to create excess stress on parts, the gap between faceplate and stem should end up the same at each corner

    in general the way to do it evenly is...

    take out the slack evenly on each bolt, then tighten each in turn a quarter or half turn following this pattern...

    stemorder_web.jpg

    test each time, when the bars are tight you can stop
    my bike - faster than god's and twice as shiny
  • andyh01andyh01 Posts: 571
    Thanks, I've ordered the £25 torque wrench from wiggle, when it arrives I'll losen off and redo following the order.

    I've just st installed a front light bracket attached to the bottom two screws of the face plate, replacing the original screws with longer ones and plastic spacers, will the longer screws and plastic spacers have an effect?
    Thanks
  • keef66keef66 Posts: 13,123
    If it says 7Nm that's usually a maximum torque. If you can get the bars to stay put at 4-5 Nm there's nothing to be gained by tightening further.

    Longer screws shouldn't change anything, but plastic spacers could possibly deform as you tighten them?

    Not sure I'd want plastic spacers on my faceplate bolts TBH
  • MatthewfalleMatthewfalle Posts: 17,380
    andyh01 wrote:
    Thanks, I've ordered the £25 torque wrench from wiggle, when it arrives I'll losen off and redo following the order.

    I've just st installed a front light bracket attached to the bottom two screws of the face plate, replacing the original screws with longer ones and plastic spacers, will the longer screws and plastic spacers have an effect?
    Thanks

    errrr - its not something the MFs would do tbh........
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • DeVlaeminckDeVlaeminck Posts: 6,322
    andyh01 wrote:
    Thanks, I've ordered the £25 torque wrench from wiggle, when it arrives I'll losen off and redo following the order.

    I've just st installed a front light bracket attached to the bottom two screws of the face plate, replacing the original screws with longer ones and plastic spacers, will the longer screws and plastic spacers have an effect?
    Thanks

    Probably be ok, worst case is your bars will snap descending at 40mph and you'll be down one set of carbon bars.

    In all seriousness you are probably better placed to judge than we are but I've known people have both bars (alloy) and faceplates snap whilst riding so judge for yourself but err on the side of caution.
    AFC Mercia women - sign for us
  • andyh01andyh01 Posts: 571
    Well.i adjusted the bar position and fitted the light bracket and tightened the bolts bk up.before the torque wrench arrived. It seemed ok been on a few rides and went to.go on club ride, just as gets to meeting point at bottom of a hill, the bars slipped ...
    Luckily I was slowing down anyway and was only a small movement and I stayed upright. I gave the club ride a miss and took bike home. It transpired, the headset had come lose.
    I've since re tightened all bolts and so far been fine
  • AlejandrosdogAlejandrosdog Posts: 1,975
    How exactly does a loose headset cause the bars to slip?
  • imposter2.0imposter2.0 Posts: 11,012
    As above. Bars slipping because loose headset = does not compute
  • MatthewfalleMatthewfalle Posts: 17,380
    i saw that last night but was shaterred so wasn't surprised that it didn't compute.

    it still doesn't compute now and i'm i.v.ing coffee.....
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • andyh01andyh01 Posts: 571
    Sorry I st to clarify, I guess it was a deep Ng that the bars had slipped a little. The movement was coming from the steamer as the headset was that lose, the steamer was moving a few mm forward.

    Seems to be all.ok now
    No feeling of.movement from bars or headset.

    I assume carbon bars can withstand stone chips without.cracking lol car flicked a stone up that hit my bars as I was passing in opposite direction.
  • imposter2.0imposter2.0 Posts: 11,012
    steamer...?
  • AlejandrosdogAlejandrosdog Posts: 1,975
    Imposter wrote:
    steamer...?
    deep NG man
  • MatthewfalleMatthewfalle Posts: 17,380
    Imposter wrote:
    steamer...?
    deep NG man

    the deepest.

    #karmaNg
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • MatthewfalleMatthewfalle Posts: 17,380
    andyh01 wrote:

    I assume carbon bars can withstand stone chips without.cracking lol car flicked a stone up that hit my bars as I was passing in opposite direction.

    of course they can

    #sriously?
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • OnTheRopesOnTheRopes Posts: 460
    Imposter wrote:
    steamer...?
    Stem I am guessing
  • AlejandrosdogAlejandrosdog Posts: 1,975
    OnTheRopes wrote:
    Imposter wrote:
    steamer...?
    Stem I am guessing

    Makes sense but what is the deep NG??????
  • imposter2.0imposter2.0 Posts: 11,012
    OnTheRopes wrote:
    Imposter wrote:
    steamer...?
    Stem I am guessing

    Nah, I think he's talking about a rice steamer...
  • AlejandrosdogAlejandrosdog Posts: 1,975
    Imposter wrote:
    OnTheRopes wrote:
    Imposter wrote:
    steamer...?
    Stem I am guessing

    Nah, I think he's talking about a rice steamer...

    Better than the Cleavland Steamer
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