Monolith

CalipERD Rim Measuring Device

The Monolith CalipERD Rim Measuring Device delivers the precision wheel builders need for accurate spoke calculations and consistent wheel performance. Designed for professional mechanics and dedicated home builders alike, this tool ensures every build starts with exact data.

With a wide 53mm throat, the CalipERD easily accommodates everything from narrow road rims to wide fat bike rims, measuring diameters between 12" and 36". The included calibration tool fine-tunes both internal and external feeler sets, guaranteeing repeatable results every time.

Accurate ERD (Effective Rim Diameter) readings eliminate guesswork, saving time and preventing costly spoke length errors on any custom build.

• Accurate and fast ERD measurement for precise spoke length calculation
• Wide 53mm throat handles rims from lightweight road to fat bike builds
• Measures rims from 12" to 36" for broad compatibility
• Includes calibration tool for consistent, reliable readings

The Monolith CalipERD simplifies wheel building by combining accuracy, versatility, and ease of use into a single dependable tool.