Tonight, I began the process of building a new wheel.

I purchased an Industry Nine Hydra Hub (MTN - 32 hole - Classic Rear Hub - ISO 6 Bolt - 12x148 HG)

Here are the calculations posted on their website: enter image description here

I am pairing it with the Spank 350 29" Rim. Here are the calculations for the rim: enter image description here

As for nipples, I purchased these: enter image description here

I checked on several different spoke calculators. This is the spoke length calculation I got:

Drive Side Spoke Length: 290.7mm enter image description here Non Drive Side Spoke Length: 292.4mm enter image description here

Drive Side Spoke Length: 290.7mm

So, I bought 290mm spokes and 292mm spokes.

But, halfway through building the wheel, I noticed the spokes are way too long... like to the point my wheel build is definitely not going to work with these spokes. I have 16 spokes on the wheel and all of them are sticking out of the outer nipple holes...

My Question:

What did I do wrong in my calculations? What is the correct spoke length?

I have this bad feeling that it has something to do with Spank's "ERD++" calculation, but I don't understand their wording:

ERD and “++” – It’s important to note that the “++” callout in Spank published ERD measurements for all our rims, refers to the height of the nipples you are using in your wheel build. You must add 2X nipple head height (specific to the nipples you have chosen), to the ERD when calculating spoke lengths. In the past ERD was usually communicated as a calculation including a standard nipple head height, (Inner Diameter of the Rim + 2x Spoke Bed Wall thickness + 2x Nipple Head Height = ERD). However, in recent years many new standards of nipples have been introduced, and nipple head heights vary. For example a standard external nipple has a 2mm head, while a DSN type nipple has a 4mm head. For this reason, Spank communicates ERD without including nipple head height, so the user can add the exact height of the nipples they have chosen for their build, (Inner Diameter of the Rim + 2X Spoke Bed Wall Thickness = ERD ++). https://spank-ind.com/apps/help-center#!faq-article-1

... Does that mean I'm supposed to add more to the ERD? I just used 602mm. If I had to add to the ERD, the spokes would be even longer, so I don't get it.

  • 3
    Are you 100% sure you've laced the spokes correctly? Do you have one side laced up with both leading and trailing spokes, or do you have 8 spokes on each side? Commented Jun 13, 2020 at 6:19
  • Did you confirm the measurements are correct when you received the parts?
    – Criggie
    Commented Jun 13, 2020 at 7:24
  • 2
    When you say you have 16 in and they seem too long, which 16 are we talking about? It's actually a really good thing Spank is doing that with their ERD measurements. Also, I have several posts here that go through how to measure ERD yourself with a caliper, ruler, or tape measure and no special tools if you want to find them to corroborate. Commented Jun 13, 2020 at 8:02
  • 1
    Similar to what @whatsisname says - there are points in the process when all the spokes are loose. I follow Sheldon's guide and when the first 16 (in your case, 18 for me as every wheel I've built has been 36-spoke) spokes are in, they're all trailing, and the hub doesn't want to sit like the picture. Instead rotates until the spokes stick out. When you've laced one side (and this should be true if you lace leading & trailing spokes on one side before doing the other) your hub flange and rim holes lie in a plane making the spokes stick out
    – Chris H
    Commented Jun 13, 2020 at 8:58
  • 1
    If the spokes are poking out of the rim holes, have you tightened the nipples on too far too early? When lacing, the nipples only go on a little way until all spokes are in. Photos could help reduce guessing
    – Swifty
    Commented Jun 13, 2020 at 10:56

1 Answer 1


enter image description hereThe spoke lengths were correct, I just laced the wheel wrong. I fix the lacing issues and now the wheel is looking good.

If you ever suspect that your spoke lengths are off, just make sure you laced the wheel correctly first.

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