FB17: Problem Solvers plugs frame holes with Bubs, adds Boosters, MisMatch 2.2, plus new gear from MSW - Bikerumor
How to convert a non boost (center lock) front hub to boost? Planning to change to rigid fork and it's only for boost. The Problem Solvers Booster looks like for 6 bolt
Problem Solvers Rear Booster & Super Booster – Hub Cycles