Wheelbuilding advice needed - spoke tensions

Alibran
Alibran Posts: 370
edited June 2012 in Workshop
I recently built my first wheel, following the instructions in Roger Musson's "Professional Guide to Wheelbuilding", and using what I think are "decent" components - DT Swiss rims, DT race spokes and Shimano 105 hubs.

Having followed all the instructions, and completed the wheel using the method of plucking the spokes to equalise the tensions, I decided to buy a tension meter to check my work (I've been told I'm tone deaf, so I suspected my tensions were seriously out). It turned out that my tensions are almost spot on, but much higher than the maximum marked on the rims - around 165kgf using rims marked with a max of 122kgf.

My first thought was to decrease the tensions, but then I checked some of our factory built road wheels, and found tensions of up to 175kgf which reduce to around 120kgf once the tyre is inflated. These are the stock wheels from entry level bikes, with Alex rims, so presumably of a much lower quality than the DT Swiss rims I'm using.

My question is, do I need to reduce the spoke tensions on my wheel, so that they are "correct" without a tyre on the rim? Or does the maximum spoke tension apply to the wheel once the tyre is fitted and inflated?

I'm leaning towards the latter because I think I will end up with fairly loose spokes otherwise, but I don't want to risk having a rim fail catastrophically during a 40+mph descent if I get it wrong!

Comments

  • Herbsman
    Herbsman Posts: 2,029
    The tension that you measure is the tension with no tyre installed.
    CAPTAIN BUCKFAST'S CYCLING TIPS - GUARANTEED TO WORK! 1 OUT OF 10 RACING CYCLISTS AGREE!
  • ugo.santalucia
    ugo.santalucia Posts: 28,301
    No need to remove the tyre, just remove the air from it. If you keep avert high tension the wheel will not stay true and the rim will eventually crack
    left the forum March 2023