A task chair is four material families doing four different jobs: a steel frame that carries load, a gas cylinder that carries the same load while moving, polymer parts that make it adjustable, and foam and fabric that make it tolerable to sit on. Most of the cost sits in the mechanism you never see.
8 parts — 5 you can see, 3 you can’t without opening it.
Steel tube with a nitrogen charge and an oil-damped piston
Nitrogen is inert and holds pressure across a wide temperature range. Steel takes the side-load from someone dropping into the seat, which is what actually kills cylinders.
Glass-filled nylon, cast aluminium on higher-end chairs
Glass fill roughly triples nylon's stiffness for a small cost increase. Aluminium is used where the base is a visible design element or the load rating is higher.
Plywood or injection-moulded polypropylene
Plywood is cheap, stiff, and easy to staple upholstery to. Moulded polypropylene lets the flex be tuned into the shape instead of relying on foam.
Cold-cure moulded polyurethane, typically 45–60 kg/m³
Density, not thickness, sets how long a seat lasts. Cheap chairs use low-density slabstock cut to shape, which compresses permanently within a year or two.
Polyester or nylon elastomeric weave over a nylon frame
The weave provides support through tension rather than compression, so it ventilates. Its tension is set at assembly and can't be adjusted afterwards.
Stamped and welded steel, with a coil spring and nylon bushings
Steel handles the cyclic load of reclining. The bushings are the usual failure point and the reason an old chair creaks.
Nylon body with a polyurethane or TPE tyre
Hard nylon rolls on carpet; a soft polyurethane tyre is required on hard floors or the wheel marks the surface.
Polyurethane or TPE over a nylon carrier
A soft skin over a rigid carrier gives comfort without losing stiffness. It's also usually the first surface to look worn.
The materials list barely predicts how long a chair lasts. Two chairs with identical spec sheets differ mostly in foam density, cylinder class, and whether the tilt mechanism uses bushings or bearings — none of which appear in a product description.
Gas cylinders and castors are standardised and cost a few pounds to replace, which makes them worth swapping. Tilt mechanisms are usually riveted and model-specific, so a failed mechanism is normally the end of the chair.
This page describes the category. Exploded reads the specific object in front of you — photograph your office chair and get a breakdown of its parts, with every guess labelled as a guess, then explore what could be built differently.
Analyze your office chair