Almost certain they'll be 6000 series, loads of places sell 'em. Ceramics ain't cheap though and honestly don't think you'll notice a difference unless you're doing about 900mph...
@TooTallTim 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.
Almost certain they'll be 6000 series, loads of places sell 'em. Ceramics ain't cheap though and honestly don't think you'll notice a difference unless you're doing about 900mph...