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Spoke Length.

Discussion in 'Bicycle Mechanics and Repairs' started by oilyrag, 6 Mar 2018.

  1. oilyrag

    oilyrag Active Member

    I have decided to try my hand at building a front wheel as the one I have has lost the wear indication completely and is somewhat concave. The spoke length calculator I used asks for 296 mm length. I have a friend who has a box of one hundred spokes the length 293 mm. In the great scheme of things would that 3 mm make any difference or am I tied to the calculated length. Thank's in advance
  2. Eddy

    Eddy Guru

    raleighnut likes this.
  3. Velochris

    Velochris Regular

    Yes. Provided you have measured correctly that is too much of a shortfall.

    Are you using black or silver spokes? I'm having a clear out of my sliver spokes and will have some in 296 if interested.
    raleighnut likes this.
  4. OP

    oilyrag Active Member

    The measurements I used are -

    OLD - 100mm
    Flange hole centres - 38mm
    Dist between inside of flanges - 67mm
    ERD 607mm
    32 Holes.
    Arrived at 296.7 mm. Front wheel.
    Last edited by a moderator: 6 Mar 2018
  5. Velochris

    Velochris Regular

    Presume 3 cross? The most important measurement is the ERD. Don't always rely on manufacturers as well. Hard to believe but they aren't always correct.

    What rim and hub are you using?
  6. YukonBoy

    YukonBoy Veteran

    Depends on the lacing. If you came up with 296mm for 3 cross, try it with 2 cross to see what length that produces.
  7. OP

    oilyrag Active Member

    3 Cr
    3 Cross. Rims are Mavic A119 etro 622 x 19. Hub is off the old wheel Joytech, dont know the model or number. A cheap and nasty set up but will be adequate for the cycling I do. Am I correct regarding the ERD that the measurement is the diameter from the heads of two nipples directly opposite each other.
  8. Velochris

    Velochris Regular

    Sort of. It is the diameter of where you want the threaded ends of the spokes to end up.

    Most measure so that the threads end level with the bottom of the slot of the nipple. If you wanted them to end up at the very top of the nipple you would have to increase the ERD. However, once the threads get to that stage they cannot keep sewing in much further so you may bottom out the thread.

    It sounds like you could use 296 or 297 but couldn't say for sure without measuring myself.
    Ajax Bay likes this.
  9. Ajax Bay

    Ajax Bay Über Member

    East Devon
    I'm not sure that the 'correct' image is 'correct' but there are others on here that can offer a far more assured opinion. The spoke in that image is too high in the nipple and would be sub-optimal for using the slot in the nipple. The nipple thread will be at least 10mm long so losing a thread (0.45mm) or two's engagement will still allow secure fastening ('tween spoke and nipple) as in the 'NO GO' image. Better a bit short than a bit long.
    And as for 'Nipple can break here': why?
    Looking for an article which addressed this I found this Park article on "Measuring ERD".
    Eddy likes this.