Determined by the rim....typically "sharp" aero rims with joint sleeves.
Mavic CXP-33 and Velocity DeepV have a very sharp profile PLUS the Velocity DeepV has a joint sleeve that increases nipple depth. Result is that if you are not careful - the bottom of your spoke wrench will scratch the anodized finish when using 10mm and 12mm nipples.
Basically, the nipple sits to deep in the rim with the wrench flats ending up to close to the rim surface.
14mm nipples are ideal for the Velocity DeepV...it's what I use when the customer okays it.
=8-)
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5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life