Spoke breaking at nipple!

flasher
flasher Posts: 1,734
edited April 2014 in Workshop
Home built set of wheels, rear 32 spoke, IRD VSR rim with Ambrosio hub using DT Comp spokes, I've now broken 2 spokes on the drive side at the nipple. After the first break I slackened all the spokes off replaced the spoke, re-tensioned and trued hoping everything would be ok, 3 weeks later another spoke has gone!

I'm starting to lose faith in the wheel and my building skills, what am I doing wrong?

Comments

  • ugo.santalucia
    ugo.santalucia Posts: 28,301
    It's quite clear your building skills need refining in some way. I can't help you... the first set I built many years ago are still around somewhere. 8)
    There isn't an obvious mistake that comes to mind... did you build the rim the correct way round? First spoke on the left of the valve hole should always be coming towards you
    left the forum March 2023
  • cpeachey
    cpeachey Posts: 1,057
    Thorn's Rohloff wheels has broken spokes at the nipple end at one time. To sort this they had rims drilled so that the nipple pointed towards the hub whereas before there was a bend at the nipple end.
    Could your wheels be the same?
  • ugo.santalucia
    ugo.santalucia Posts: 28,301
    The VSR is an offset rim, which leads to the following question... did you lace it the correct way round?
    Look at the image on the right

    mqdefault.jpg
    left the forum March 2023
  • flasher
    flasher Posts: 1,734
    Yes, laced the correct way, double checked that when I first made it up, and the nipples certainly look to be pointing at the correct angle.
  • Monty Dog
    Monty Dog Posts: 20,614
    If there was a big variation in tension on the drive side spokes then you have probably over-stressed all the spokes on that side that will result in premature failure - best long-term solution would be to replace the drive-side spokes and try to tension them more evenly
    Make mine an Italian, with Campagnolo on the side..
  • flasher
    flasher Posts: 1,734
    I've replaced the broken spoke, checked all the tensions and they're all pretty even, if it breaks again I shall take it to Ugo for a rebuild an he can take the responsibility!
  • ugo.santalucia
    ugo.santalucia Posts: 28,301
    Flasher wrote:
    I shall take it to Ugo for a rebuild an he can take the responsibility!

    Maybe it's not even your fault... maybe that rim is badly designed and the nipples don't sit correctly. I have never used it, so I can't really comment
    left the forum March 2023
  • cycleclinic
    cycleclinic Posts: 6,865
    There are badly designed rims out there. There is a alex MTB rim that I did a rebuild on but there was a bend in the spoke at the nipple. I did warn the customer that this is were spoke failure might happen. He came in this week guess what what I predicted happened but took 8 months or so. If there is a bend in the spoke at the nipple you can be sure the spoke failure is more likely.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • andrew_s
    andrew_s Posts: 2,511
    CPeachey wrote:
    Thorn's Rohloff wheels has broken spokes at the nipple end at one time
    The Rohloff problem is a standard one for large diameter hubs. If you have a large hub relative to the rim, and too many spoke crosses, the spokes meet the rim at too large an angle for the nipple & seat to accommodate, and you get nipple end spoke breakages. Fewer spokes makes it worse too.
    To avoid broken spokes, it's either put a permanent bend in the spoke just by the threads, or manipulate the rim nipple seats so they will accommodate the forwards/backwards spoke angles required (i.e not pointing at the axle as normal).

    For the OP's wheel, it may be worth rebuilding with Sapim polyax nipples, which accommodate more of an angle than normal.
  • flasher
    flasher Posts: 1,734
    andrew_s wrote:
    For the OP's wheel, it may be worth rebuilding with Sapim polyax nipples, which accommodate more of an angle than normal.

    Interesting, as I've ordered a new set of Sapim Race spokes to do a complete rebuild. Do you know if the polyax nipple is Sapim's std nipple?