spoke length - round up or down?

jomoj
jomoj Posts: 777
edited June 2012 in Workshop
quick question - about to order some spokes for a build and the lengths I get out of various spoke calcs are 293.9 for the front (obviously round up to 294) and for the back 292.9 and 291.4. So for these should I round up to 294 and 292 respectively if I can't get 291 and 293 lengths?

cheers

Comments

  • Herbsman
    Herbsman Posts: 2,029
    I rounded up, and the spokes were 2mm too long. Poking out of the top of the spoke nipple.

    Thank goodness rims are double-walled.

    I'd prefer to risk having spokes which, when tensioned correctly, are 2mm below the top of the nipple than 2mm above.
    CAPTAIN BUCKFAST'S CYCLING TIPS - GUARANTEED TO WORK! 1 OUT OF 10 RACING CYCLISTS AGREE!
  • Peejay56
    Peejay56 Posts: 41
    Jomoj - round up. It's important that the spoke has full threads engaged in the nipple. If you do your calc's right, when pulled up , the spoke usually ends up just about level with the top of the nipple - that's my experience from the wheels I have built. I use the Sapim spoke length calculator.

    Check the DotBike website - they sell DT Swiss and Sapim spokes in all the lengths you want including 291 and 293 mm.

    Pete.
  • ugo.santalucia
    ugo.santalucia Posts: 28,273
    In fairness 1 mm plus or minus doesn't really make any difference. Even if the spoke protrudes 1 mm out of the nipple head, who cares? You'll have to unwind it with a spoke key anyway, before unscrewing it.
    Dotbike only seels boxes of 100, If I were you I would use ACI DB spokes, cheap and good quality... I think Sdeals has the sizes you are looking for too
    left the forum March 2023
  • crankycrank
    crankycrank Posts: 1,830
    Also try here to get a second verification of the spoke measurement. http://lenni.info/edd/
  • Herbsman
    Herbsman Posts: 2,029
    crankycrank wrote:
    Also try here to get a second verification of the spoke measurement. http://lenni.info/edd/
    That's the one that I used, and gave me spoke measurements that turned out to be too long!
    CAPTAIN BUCKFAST'S CYCLING TIPS - GUARANTEED TO WORK! 1 OUT OF 10 RACING CYCLISTS AGREE!
  • cycleclinic
    cycleclinic Posts: 6,865
    Spoc cal download from sheldon's brown site is good. so long as the imput information is good. The ERD is critical. A few mm out on the hub measurements make little difference. I also round up spoke lengths. Often 1mm of spoke protudes but big deal. So long as the nipple does not bottom out when tensioning the spoke length picked will be fine.

    Sapim Race spokes are sold in 1mm incrments in the more common size range. I have the lengths you require @0.45p each. If you want them let me know.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • ugo.santalucia
    ugo.santalucia Posts: 28,273
    thecycleclinic wrote:
    Spoc cal download from sheldon's brown site is good. so long as the imput information is good. The ERD is critical. A few mm out on the hub measurements make little difference. I also round up spoke lengths. Often 1mm of spoke protudes but big deal. So long as the nipple does not bottom out when tensioning the spoke length picked will be fine.

    Sapim Race spokes are sold in 1mm incrments in the more common size range. I have the lengths you require @0.45p each. If you want them let me know.

    Yes, that's the best one as it does things like paired holes hubs, which other calculators don't. It's also got a fairly good database of rim and hubs measurements.
    left the forum March 2023
  • jomoj
    jomoj Posts: 777
    thanks for the replies all, much appreciated. I've used spocalc and a couple of the other calculators and they all agreed. ERD is on the rim sticker and I got the hub dimensions from the shimano tech docs site so hopefully will be accurate.

    Spoke wise, I was considering ordering some black DT spokes from rose bikes and they only had even lengths but sapim race where my next choice as I'm not too fussed by the colour in all honesty.
  • cycleclinic
    cycleclinic Posts: 6,865
    A Sapim's are cheaper I would go with those. Also measure your ERD. The sticker is normally right but rims do sometimes vary. 1mm chnage on the ERD make a difference to the spoke length. For the time it takes to measure, measure to be sure!
    http://www.thecycleclinic.co.uk -wheel building and other stuff.

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