Originally Posted by
Rubato
I'm about to build my 7th wheel and still learning. I bought a nice shiny Pacenti rim and the sticker reads "ERD 611." Because I'm still trying new things, I measured it, several times, in several locations, and I get an ERD of 615.
I cut 2 spokes to 200 mm and screwed a nipple on each one until the spoke was flush to the top of the nipple. I put 'em in opposite holes on the rim and carefully measured the space between them. When I total the numbers, my measurements are always higher than the published ERD.
If I calculate spoke length with the published numbers the spokes would probably reach to the bottom of the screw slot.... Why would I waste the last remaining bit of threads for such a thing?
Am I missing something simple?
In this thread I explain what ERD really is and remind folks that it is NOT a static reference, white paper spec, etc.:
http://www.bikeforums.net/showthread...?highlight=erd
Post
#56
In this video I explain how certain variables influence aiming points when measuring your own ERD:
http://www.youtube.com/watch?v=gCXFKN9JvCQ
Most important thing of all is the reminder repeated often here on BikeForums:
"It's always best to measure your own ERDs."
=8-)
__________________
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