Originally Posted by
Scooper
I wouldn't go -2mm because you are getting too low a thread engagement and also the shorter spokes will be more problematic when lacing/tensioning because you will be getting tight spokes too early in the build process unless you modify your nipple driver accordingly.
[/I]
Those photos show 20 threads on the spoke and 18 threads on a 12mm nipple with 2 threads per mm. So if you had to round down 2mm you'd have at least 14 threads engaged; that's not even close to being too low.