Originally Posted by
mrrabbit
If it is a DT Swiss brass 12mm nipple, their 9.5mm threaded spokes will stop about .50 - .75mm past the top.
DT Swiss alloy 12mm nipples tend to be a little more liberal and will often allow the same spoke to protrude as much as 2.0mm past the top.
Not sure why they do this - I've never asked...
=8-)
I've been using the alloy flavor.
To speculate I'd guess the threading allows you to aim for the top with the same error tolerance for long (run out of threads) and short (don't make it through the rim, load the nipple in tension, and break it) spokes provided that you're using double-walled rims where the excess length won't hurt.
With brass nipples you can get away with being a lot shorter