I used an online spoke calculator for, uh, calculating the spoke lengths that I need. The results of the calculator are as follows:

  • Front
    • Left - 276.5mm
    • Right - 277.8mm
  • Rear
    • Left - 275mm
    • Right - 273.4mm

The rims are WTB KOM Tough i35 27.5" with an ERD of 568mm. The hubs are Shimano XT M8110-B.

Thing is, LBSs here only have limited lengths for different tire sizes. For 27.5", they only have 270mm and 275mm. Will the 275mm work for my wheels or should I just go look for the correct lengths online?

  • @ChrisH thanks for that link! Yes, I think that answers my question!
    – dork
    Mar 25, 2021 at 14:09

1 Answer 1


The length is what matters, so if they claim to have the right length for a different wheel you could use those - but it would be a sign of a clueless shop.

Otherwise better to order the correct length. 275mm for that front right is too short, nearly 3mm under, while for the rear right you're either under or over. Many places stock 2mm increments; my local supplier does 1mm

  • Actually this is the first time I'm going to have a wheel built with different spoke lengths. I had the wheels of my fixed gear built but I bought the spokes online. I think most, if not all, bike shops here just carry 2 lengths per tire size out of convenience for them since they don't know if the other lengths will be sold or not.
    – dork
    Mar 25, 2021 at 11:52
  • 5mm increments to me sounds like just enough stock to cover (most) repairs. For a planned build I'd want to get it right. I'm about to link to a previous question that I think covers what you need to know. The consensus there seems to assume 2mm increments. In this case the rear right is actually the biggest issue (thinking further) you'd have to go under to be sure of not running out of thread, but this is the tightest and most stressed set of spokes on the whole build and you'd be a lot under.
    – Chris H
    Mar 25, 2021 at 12:38
  • I've just realised - your previous custom build was a fixie. They're not dished and tend to be symmetric so you'd end up with the same length left/right. I couldn't rule out the same front/rear.
    – Chris H
    Mar 25, 2021 at 17:10

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