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)
I am pairing it with the Spank 350 29" Rim. Here are the calculations for the rim:
I checked on several different spoke calculators. This is the spoke length calculation I got:
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...
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.