Polyurethane caster wheels, specified by hardness — not colour.

Polyurethane earned its place as the standard caster tread by being good at everything that matters indoors: it carries serious load, protects concrete, epoxy and tile, runs quietly, resists cuts and chunking, and does not mark floors. But 'polyurethane' on a quotation is the beginning of a specification, not the end of one. Two polyurethane caster wheels of the same diameter can differ in tread hardness by ten Shore points, sit on cores of different materials, and carry bearings chosen for different jobs — and they will perform like different products.

Core materials: what the tread sits on

The lead CASTOVELLA configurations sit on cast iron — the heavy duty line is built on it — because most of our buyers are importers and OEMs whose customers run loaded carts all day. If your application is weight-sensitive or corrosion-sensitive, say so: the same tread on a different core is a different quotation, and we would rather quote it correctly the first time.

Tread hardness, in plain terms

Hardness is quoted in Shore A. As a working guide: softer treads (around the mid-80s Shore A) grip better, cushion shock and protect delicate floors, but roll with more resistance and can flat-spot under long standing loads. Harder treads (mid-90s Shore A) start and roll easier and carry more, at the price of noise and floor marking risk on soft surfaces. The exact compound and hardness range for your order is stated on the quotation and checked on the sample with a durometer — a thirty-second test that settles arguments before they start.

PU vs the alternatives

Against rubber, polyurethane carries more load per inch of width and resists the cuts that shred rubber treads in metalworking environments. Against nylon, it is quieter and far kinder to floors, though nylon wins on pure capacity per dollar in dry, rough-floor duty. Against phenolic, it loses on heat — which is why high temperature work has its own line. The full comparison, including where each material fails, is in our PU vs rubber vs nylon guide.

Where this line ships

Polyurethane caster wheels anchor the heavy duty range (4, 6 and 8 inch), the furniture line at 75 mm, and a wide band of medium duty equipment casters in between. If you are building a private-label range, this is usually the line to anchor it on: one tread family, several cores and sizes, one locked specification format across the range.

The specification we lock before quoting

A quotation is only comparable when the specification underneath it is fixed. For this line — as for every CASTOVELLA line — the written quotation locks these six variables, and the production sample is checked against them before bulk production is approved:

• Wheel diameter and width — width is both a performance variable and the US tariff classification variable; it is measured on the sample, not copied from a catalogue.
• Tread material and hardness — stated as a Shore hardness range, so the bulk shipment can be checked against the approved sample.
• Bearing type — plain, roller or precision ball bearing, named on the quotation; bearing swaps are the most common silent downgrade in this industry.
• Fork and top plate thickness — measured in millimetres and stated, because fork flex is where cheap heavy duty casters fail first.
• Load capacity and test method — capacity per caster with the test convention named (EN 12532 / ANSI ICWM), never a bare number.
• Finish and hardware — zinc plating, stainless grade or coating stated per component, not per marketing photo.