Originally Posted by
Looigi
If you are trying to estimate ERD via rim height, then lots of things come into play that wouldn't when measuring it directly. So though you may estimate ERD from rim height, the other variables probably will not allow sufficient accuracy for it to be of value in determining proper spoke length.
Actually the Phil ERD measuring kit uses this method very well. But like any measuring the person doing the measuring is the bigger variable. Andy.
Edit- I've used the three common measuring systems and find that the "across the rim with spokes or rods" method to be the hardest to work with. Yet it is what most will try first. Andy.