Stem bolts : What size?

Discussion in 'Bicycle Mechanics and Repairs' started by RSV_Ecosse, 23 Apr 2010.

  1. RSV_Ecosse

    RSV_Ecosse Senior Member

    What size stainless allen headed bolts are usually used as the 4 fitted to road bike stems?. I want to replace mine as they are looking a bit dull and worse for wear but I have no idea what size they are?. Had a dig around online and some say they will likely be M5x16 but I have also read of a few other sizes that are possibles?. I once knew a guy who could simply look at any screw, bolt whatever and tell you exactly what size it was but unless a component has the size marked on it, I'm hopeless at that!!. :blush:

    Or is there a way to measure the things and tell?. Cheers.
     
  2. Rob3rt

    Rob3rt Man or Moose!

    Location:
    Manchester
    They are M5x20 (with a 4mm hex head) on this fuji stem ive got lying on my desk.

    To measure take one out and hold against a ruler, or if you are fancy (like me :blush: - jokes) then use a set of digital (or manual) calipers or micrometer to tell measure.
     
  3. OP
    OP
    RSV_Ecosse

    RSV_Ecosse Senior Member

    Ta.

    Is it ok to just use anodised alloy bolts in the stem or should they really be stronger, like titanium for example?.
     
  4. Rob3rt

    Rob3rt Man or Moose!

    Location:
    Manchester
    I have no idea if Im honest, I used the bolts that came with the stem when I changed the stem over from the Fuji one to a better one.

    If in doubt go with the stronger option, dont want something to sheer when you got your weight on it and go faceplanting.
     
  5. e-rider

    e-rider crappy member

    Location:
    South West
    DON'T use alloy bolts - no no no! Not strong enough for stems. All stems come with either stainless steel or titanium bolts (or for example, zinc plated steel on cheapo crap stems).
     
  6. OP
    OP
    RSV_Ecosse

    RSV_Ecosse Senior Member

    Cool, I'll grab a set of Ti ones online somewhere.

    Cheers for the info folks. :blush:
     
  7. redddraggon

    redddraggon Blondie

    Location:
    North Wales
    Huh, steel and the titanium used for bolts are alloy :blush:
     
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