What is ERD?
ERD, short for Effective Rim Diameter, is the rim diameter measured at the nipple seats in the spoke holes, plus the thickness of the two nipple heads.
Take a 29-inch mountain bike rim as an example
The rim's height is 30mm, 29er mtb rimwhole diameter is 633mm
The thickness of the rim spoke hole position is 3.5mm,
So the rim ERD is 633-30-30+3.5+3.5 = 580mm
For each hub model we sell, we have the data of the spoke length, you can also contact us directly
Contact: Silver Xia
Add: Jinyang dong Rd 1055, Magnate Light capital gatehall 5A- 4F-766, 215300 Kunshan China