A flat tyre stops a manual wheelchair dead, and drive wheels of this size are the ones most commonly running pneumatic tyres. This Schwalbe inner tube is the replacement for that wheel, made from butyl rubber with a Schrader valve, which is the same fitting as a car tyre and can be topped up at any service station or with a standard floor pump.
Butyl holds pressure well, so the wheels stay at the pressure they were set to for longer. That matters more than it sounds: a soft tyre is harder to push, wanders under the user and wears the rim.
Worth keeping a spare in the workshop or in the client’s bag, since a tube change is a quick job for anyone comfortable with bike tools.
