I imagine it needs to carry the slip ring for the horn and other associated guff through it on top of being just a spacer
@mcmyk started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
I imagine it needs to carry the slip ring for the horn and other associated guff through it on top of being just a spacer