But the bolt that caps the reservoir is metal. Just be careful and don't overtighten stuff.
It's made of really soft aluminium with only a 2 or 2.5mm hex which strip out way before you can damage the threads. It looks like the metal adapter there has wrench flats, and a sharp steel thread. Different kettle of fish. Metal =/= metal
@chiroshi 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.
But the bolt that caps the reservoir is metal. Just be careful and don't overtighten stuff.