Which derailleur is that?
No Derailleur fitted, Rohloff speedhub, with a Vostok triangle 135mm, Vostok tensioner with adjustable chainline.
https://www.sjscycles.co.uk/search/?term=Vostok%20
@Rhobbs 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.
Which derailleur is that?