DT Swiss PHR Washers. Pro Head Reinforcement System (PHR) has a larger and more spherical contact area and is designed to balance loads transferred to the rim. The PHR system acts like a ball and socket interface allowing the spoke to pivot and follow the perfect trajectory from hub to rim.
- Pro Head Reinforcement System (PHR) has a larger and more spherical contact area and is designed to balance loads transferred to the rim. The PHR system acts like a ball and socket interface allowing the spoke to pivot and follow the perfect trajectory from hub to rim