Special Product – CalipERD with Green Nylon/Glass Body, 1M Length, Brass Adjuster screws

Made for CABDA Expo 2023

This tool measures Effective Rim Diameter – the most critical dimension when calculating spoke length.

The current standard for measuring Effective Rim Diameter (ERD) is using two rods of a known length and inserting them through opposite holes in a rim. Then the overlap is measured (somehow) and that number subtracted from the overall sum of both rods.

If that sounded bad – or you glossed over it – nice work! You recognize a terrible process when you see it.

That’s why this tool exists.

• Provides direct measurement of rims
• Reduces errors in spoke calculation to save time and money
• Allows perfect spoke length by determining the correct nipple seat diameter and nipple height
• Measures ERD of nearly any rim!
  • up to 750mm reliably (fits 32″ and 36″ rims)
  • 125mm minimum (~ 12″)
• Precise to within .5mm
• Interchangeable Feelers for different applications
  • includes Standard Nipple Set and Internal Nipple Set
• Includes calibration tube

Use cases include:

• Verifying Manufacturer Stated ERD
• Checking factory specifications
• Obtaining Data-driven roundness of a rim
• Use for Nipple Seat Diameter or calibrate for exact Effective Rim Diameter

CalipERD© 2023 Monolith Tool