In article ,
says...
Last night, I built a new rear wheel for cross riding using a Record
36 hole hubs, a Ritchey OCR Comp rim (called Trekking on web site) and
DT 14/15 spokes.
In doing the research, I noticed that Ritchey's web site gave the ERD
as 596 mm whereas Damon Rinard's Spocalc gave it as 605 mm. Perhaps
Ritchey has redesigned the rims?
At any rate, I called Ritchey and the rep talked to a wheel builder
who gave the ERD 599. Hmm... Right between the two values...
I plugged the 599 value in Spocalc and built the wheel using 290's on
the left and 288's on the right. At this point, I've tensioned them
to 70 kg on the left and 115 on the right.
On inspection, I noticed that the left side as 2-3 threads exposed all
around whereas the right side has 5-6 threads exposed. I'm comcerned
that the spokes are too short and I don't have enough threads embedded
in the brass nipples.
Is this wheel safe or should I rebuild it with longer spokes?

I would rebuild with the proper length spoke. I sounds like your spokes
are too short by a few mm. If you look at your spoke nipples you can see
that they are not threaded all the way. About half the nipple is unthreaded.
So if you can see exposed threads, there are more unexposed threads that
are not engaging the nipple.
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Alex