Chainring bolt length

fixiebob
fixiebob Posts: 222
edited November 2008 in Road general
Hi all i started winter trainning on my fixie the other day running 48 - 16 fairly flat where i live but when i turned into a strong headwind i really struggled.
My bike is a track frame that i put a road fork on so i could fit a brake, the cranks are miche and square taper.
Now to my question I have an old set of square taper dura ace cranks and a 105 42 tooth inner chain ring firstly can i put the 42 tooth ring on outside of crank and keep chainline and the bolts have come of a double setup do i need shorter ones.

Thanks in advance :?:

Comments

  • scherrit
    scherrit Posts: 360
    All do-able, neatest way is to mill off the step that supports the inner ring and drill a recess for the back end of the (shorter) chainring bolts in the crank spider. You may get away with just using shorter bolts (and no machining), just be sure that they have enough thread engaged- this will be less pretty and you should check the tightnesss periodically.
    Good luck,
    S.
    If you're as fat as me, all bikes are bendy.
  • fixiebob
    fixiebob Posts: 222
    Thanks all i got shorter bolts and am now spinning away happily on 42 - 16 chainline spot on. :D
  • itboffin
    itboffin Posts: 20,052
    Whilst on the subject is there anything wrong with just using normal nuts and bolts rather that bike specific?
    Rule #5 // Harden The Feck Up.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.
    Rule #12 // The correct number of bikes to own is n+1.
    Rule #42 // A bike race shall never be preceded with a swim and/or followed by a run.
  • scherrit
    scherrit Posts: 360
    Yes, very wrong....

    IF you could get exactly the correct diameterbolt or set screw so that the ring was unable to move around much even with the bolts/screws loose then perhaps you could use a washer and nut on the back. BUT there is very little space and the risk of these bolts loosening or shearing if run loose, or droppping out or fatigueing (sp??) from a little movement is NOT worth taking in my view.

    If these bolts are loose then there is a nasty shearing force on these little (safety critical) bolts. Imagine for a moment what would happen if you were standing on the pedals when a chain breaks or the chainring folds, or the bolts shear... it's most likely to be quite nasty......
    Cheers,
    Scherrit.
    If you're as fat as me, all bikes are bendy.
  • itboffin
    itboffin Posts: 20,052
    scherrit wrote:
    Yes, very wrong....

    IF you could get exactly the correct diameterbolt or set screw so that the ring was unable to move around much even with the bolts/screws loose then perhaps you could use a washer and nut on the back. BUT there is very little space and the risk of these bolts loosening or shearing if run loose, or droppping out or fatigueing (sp??) from a little movement is NOT worth taking in my view.

    If these bolts are loose then there is a nasty shearing force on these little (safety critical) bolts. Imagine for a moment what would happen if you were standing on the pedals when a chain breaks or the chainring folds, or the bolts shear... it's most likely to be quite nasty......
    Cheers,
    Scherrit.

    Too late...

    I'll let you know how it goes :wink:
    Rule #5 // Harden The Feck Up.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.
    Rule #12 // The correct number of bikes to own is n+1.
    Rule #42 // A bike race shall never be preceded with a swim and/or followed by a run.

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