Originally Posted by
aaronmichael
Another wheel building question here. I'll try to make this short and sweet.
I'm a manager at a LBS and I had a customer bring in an electric bicycle wheel to me the other week to rebuild it because the rim was damaged. It was originally laced with a 2x pattern and I assumed this was because of the size of the hub limited it from being laced 3x (because why else would it not be laced in a 3x pattern?). Anyway, I had to learn how to lace 2x and the end result gave me spokes that were too long and I'm going to have to rebuild it again.
Just today I had another customer bring me a 20" Promax wheel and would like to have it laced to a NuVinci hub that also has a very large flange diameter, but not as wide as the Bafang motor in the other wheel. My question is, will I be able to lace the Promax/NuVinci wheel with a 3x pattern or will the spokes overlap too much with this options. Any advice or feedback always appreciated, thank you!
I use this spoke length calculator:
https://www.wheelpro.co.uk/spokecalc/
It gives info when there is overlap (and how much spoke head overlap there is).
With hubs that have very large flange diameter, paired with rims smaller than "28 inches", another concern regarding the max. number of crosses is the angle at which the spokes enter the rim.
Sapim HM nipple washers can help with that, on some rims, allowing for the nipple to be set at an angle, more "naturally" (they will affect the spoke length calculation -
measure rim ERD with them installed).
So it does boil down to a bit of trial and error: lace, see if the spokes are too bent at the rim, then try with one cross fewer (and shorter spokes). I aim for the highest number of crossings achievable, since it does make a stronger wheel (all else being equal, properly built, no too much spoke head overlap, and with no severe angle at the spoke rim entry).
Writing the measurements down helps for the future builds.