Rubber Castors.

What are Rubber Castors?

Rubber castors, also known as rubber wheel castors, are the floor-friendly part of Accu’s Castors & Wheels range, pairing a rubber tread with a steel or plastic housing to give quiet, cushioned movement on hard floors. The tyre gives them away: a band of solid or elastic rubber in black, grey, blue or silver grey, wrapped around a harder wheel centre of steel, aluminium or plastic. That softer tread spreads the load and soaks up shocks and floor joints, so equipment rolls quietly and delicate loads arrive without being jolted.

Where a standard is listed, it is mainly EN 12532, for industrial equipment moved at up to 4 km/h, with EN 12530 covering castors for institutional settings. They suit workshops, warehouses and assembly halls with sealed or painted floors, as well as laboratories, light production areas and any trolley carrying noise-sensitive or fragile loads.

How Rubber Castors Work

A rubber castor fixes like any other, through a top plate, a bolt hole or a threaded stem, but the tread does most of the work. Under load the rubber deflects slightly where it meets the floor, spreading the contact patch so the pressure on the floor is lower and small bumps, cable covers and expansion joints are absorbed rather than passed up into the frame. Solid rubber treads at 80 to 87 Shore A stay relatively firm, while vulcanised elastic rubber at 63 to 68 Shore A is bonded to an aluminium or polyamide centre and gives noticeably more cushioning without giving up load capacity. That same deflection means rubber takes a little more effort to start rolling than a hard polyamide or polyurethane wheel, which is the trade-off for quieter, gentler running.

Consider a tooling trolley in an aircraft assembly hall, carrying 350 kg of jigs and fixtures on a 100 kg frame across a painted epoxy floor crossed by cable protectors. Assuming only three castors bear at any moment, each one takes 150 kg, just inside the 160 kg rating of a 100 mm castor with a non-marking vulcanised elastic rubber tread. The soft 63 Shore A tread rolls over the cable protectors without jolting the jigs in their cradles and is designed not to leave black tracks across floor markings that form part of the hall’s safety layout. A hard polyamide wheel of the same size would carry more, but it would clatter over every protector and pass each impact straight into the load.

Materials Rubber Castors Are Made From

Accu’s rubber castors combine a rubber tread with engineering-grade metals and plastics in the housing and wheel centre, each chosen for load capacity, floor protection and the working environment:

• Rubber: The tread on most of the range, in solid and elastic forms and in natural and synthetic compounds, from 63 to 85 Shore A.
• Rubber - TPR: A thermoplastic rubber tread at 87 Shore A on a polypropylene centre, used on lighter castors rated up to 100 kg.
• Steel: Pressed steel housings in medium and heavy-duty grades, blue passivated or zinc plated, plus pressed steel wheel centres beneath solid rubber tyres.
• Stainless Steel: Housings for the heat-resistant castors in this range, rated Excellent (5 of 5) for corrosion resistance.
• Aluminium: A rigid wheel centre beneath vulcanised elastic rubber on the highest-capacity castors, rated up to 450 kg.
• Plastic - Nylon: The centre beneath many elastic rubber treads and the material of the silver grey LEVINA housings.
• Plastic - PP: Polypropylene wheel centres beneath solid rubber and thermoplastic rubber treads.

The tread itself is specified under Tread Material, in the following types:

• Black Solid Rubber: A firm 80 to 85 Shore A tread for general duties, on castors rated from 70 kg to 205 kg.
• Non-Marking Solid Rubber: The same firm 80 Shore A tread in a non-marking compound, rated from 70 kg to 100 kg.
• Black Vulcanised Elastic Rubber: A soft 68 Shore A tread on aluminium centres, rated from 300 kg to 450 kg and Excellent (5 of 5) for noise.
• Non-Marking Vulcanised Elastic Rubber: A soft 63 Shore A tread designed not to mark floors, rated from 160 kg to 400 kg.
• Thermoplastic Rubber: A firmer 87 Shore A tread for light apparatus and equipment, rated from 30 kg to 100 kg.
• Damping, Heat Resistant: A 75 Shore A tread on stainless steel castors, rated for temperatures up to 250 °C.

Accu’s existing rubber castors also use natural and synthetic rubber tyres in grey, dark grey, black and blue.

Sizes & Types of Rubber Castors Available

Accu’s rubber castors are available with treads from 63 to 87 Shore A and in sizes and fixings to suit light apparatus through to heavy trolleys:

• Wheel Diameter (D): 32 mm to 200 mm.
• Wheel Width (T): 15 mm to 50 mm.
• Mounting Height (H): 34 mm to 250 mm.
• Approximate Load Capacity: 25 kg to 450 kg.
• Tread Hardness: 63 Shore A to 87 Shore A.
• Castor Type: Swivel Castor or Fixed Castor.
• Braked/Unbraked: Braked or Unbraked.
• Fixing Type: Bolt Hole Fixing; Rectangular Plate; Square Plate, 60 x 60 mm; Rectangular Plate, EN R42, 105 x 85 mm; Rectangular Plate, EN R43, 137 x 105 mm.
• Thread Size: M10 x 25 to M12 x 30.

Rubber treads stop at 450 kg, reached by the 200 mm castors with black vulcanised elastic rubber, so heavier loads move to polyurethane or polyamide wheels in Accu’s Heavy-Duty Castors range. Non-marking treads cover 80 mm to 200 mm wheels and loads from 70 kg to 400 kg, while the stainless steel, heat-resistant options are limited to two 100 mm castors rated at 80 kg. Threaded stem versions run from 40 mm to 100 mm and carry up to 80 kg. Replacement rubber castor wheels for many of these castors are listed separately in the Castors & Wheels range.

Where outright load capacity, wear life or easy rolling matter more than cushioning, why not browse Accu’s Plastic Castors, which cover polyurethane and polyamide wheels.

FAQ

Q: Are rubber or polyurethane castors better?

A: Neither is better across the board, as it depends on what matters most. In Accu’s range, rubber castors are rated quieter, with most scoring Very Good (4 of 5) or Excellent (5 of 5) for noise against mostly Good (3 of 5) for polyurethane, and they cushion shocks better on uneven floors. Polyurethane wears better, rated Very Good (4 of 5) against Good (3 of 5) for rubber and usually carries more on the same size of wheel: an 80 mm castor is rated at 150 kg with polyurethane but 70 kg with solid rubber. Elastic rubber narrows that gap, and at 200 mm it carries 400 kg against 350 kg for a polyurethane castor in the same housing.

Q: What are soft rubber castors?

A: Soft rubber castors use an elastic rubber tread, vulcanised onto an aluminium or polyamide wheel centre, that is noticeably softer than standard solid rubber. In Accu’s range the elastic treads sit at 63 to 68 Shore A against 80 to 87 Shore A for solid and thermoplastic rubber, so they deflect more under load, absorb shocks and floor joints better and are rated among the quietest-running castors. Despite the softer tread they carry more than solid rubber, from 160 kg to 450 kg per castor.

Q: Do rubber castors mark floors?

A: Some can. Black rubber treads can leave marks on light-coloured or sealed floors, particularly when castors are swivelled under load, which is why non-marking treads are listed separately. Non-Marking Solid Rubber and Non-Marking Vulcanised Elastic Rubber are designed not to mark floors and are available on 80 mm to 200 mm castors rated from 70 kg to 400 kg. Where marking is critical, it is worth testing a castor on a small area first, as cleaning chemicals and heat can also affect how any tread behaves.

Bespoke Rubber Castors Manufacture.

High precision, bespoke manufacture of Rubber Castors to customer specification. State of the art facilities specialising in both small batch prototyping and large scale manufacture.