All of Phil’s threaded bottom bracket cups will fit onto any of their bottom bracket cartridges produced by Phil Wood since 1971. They are an interference fit with the bottom bracket, and will require our proprietary Phil Wood bottom bracket installation tool (unchanged since 1971) to install. Cups will ship with a small tube of their thread retaining compound. We supply these alloy cups in appropriate English threads for installing on your Brompton.
Please chase the threads on you bottom bracket prior to installation.