Fixed Castors.

What are Fixed Castors?

Fixed castors, also known as rigid castors or fixed castor wheels, are the tracking half of Accu's Castors & Wheels range, keeping equipment rolling in a straight line while swivel castors take care of the steering. The wheel is held in a fork fixed solid to the top plate, so a fixed castor looks like a swivel castor with the swivel head taken out and the wheel sitting directly beneath the plate. With the castor wheels fixed in one direction, they resist sideways drift and give a trolley or machine base a stable, predictable line when it is pushed over any distance.

Most fixed castors with full specifications sit under one of four European standards, ranging from EN 12528 for furniture castors to EN 12533 for industrial equipment moved at 4 km/h to 16 km/h, with EN 12530 and EN 12532 covering institutional settings and industrial use up to 4 km/h in between. They are used on trolleys, platform trucks and roll containers, on carts and rigs that shuttle back and forth along a line and on heavy transport frames that need to hold a straight course.

How Fixed Castors Work

A fixed castor bolts to the underside of the equipment through its top plate, with the fork pressed or cast as a single rigid bracket around the wheel axle. With no swivel head, there is no swivel offset or swivel radius to allow for and no bearing between plate and fork to wear or work loose. The wheel can only roll in the direction it is mounted, so sideways force from an uneven push or a cambered floor is resisted at the tread rather than turning the castor. That is why they are fitted in pairs on a common axis, with swivel castors at the other end doing the steering.

A batch oven trolley in a powder coating shop shows why: loaded with 220 kg of hung parts on an 80 kg frame, it is pushed straight into a curing oven running at around 200 °C. Divided across three castors rather than four, the load comes to 100 kg each, inside the 125 kg rating of a 100 mm stainless steel fixed castor with a heat-resistant thermoset wheel rated up to 250 °C. With the fixed pair at the oven end and heat-resistant swivel castors at the handle, the trolley runs square through the oven door instead of crabbing sideways and clipping the frame. Standard polyamide wheels are rated to 80 °C, so at curing temperature they would be running far outside their rating.

Materials Fixed Castors Are Made From

Accu’s fixed castor wheels and housings use engineering-grade materials picked for rigidity, rolling performance and the conditions on site:

• Steel: Rigid pressed steel brackets in medium to extra-heavy-duty grades, finished in blue passivation or zinc plating.
• Stainless Steel: Fixed brackets for wet and chemically aggressive environments, scored Excellent (5 of 5) for corrosion resistance on the ALPHA STAINLESS series, with polyamide-wheeled versions working down to -40 °C.
• Cast Iron: Solid KAPPA fixed brackets and grey cast iron wheel centres, behind heavy-duty fixed castor wheels rated up to 1,200 kg.
• Aluminium: Lightweight wheel centres that stay round under load, used beneath cast polyurethane and elastic rubber treads.
• Rubber: Solid and elastic rubber tyres that cushion the ride on straight runs, including non-marking versions for finished floors.
• Rubber - TPR: Fitted to the 32 mm compact fixed castor, a thermoplastic rubber tread at 87 Shore A.
• Plastic - PUR: Treads of injection moulded or cast polyurethane at 42 Shore D, balancing straight-line rolling ease with floor protection.
• Plastic - Nylon: Polyamide wheels in every fixed size from 14 mm to 200 mm, rolling easily on hard floors.
• Plastic - PP: Light, rigid polypropylene used as a wheel centre beneath rubber treads.
• Plastic - Phenolic: Black phenolic wheels on fixed castors rated 100 kg to 150 kg, with a single heat-resistant thermoset version for temperatures up to 250 °C.
• Plastic - TP: Black thermoplastic wheels on the two stainless steel fixed castors, rated at 101.8 kg and 152.9 kg.

Sizes & Types of Fixed Castors Available

Accu’s fixed castors are available in the following sizes, plates and load ratings, from 14 mm compact wheels to 200 mm heavy transport wheels:

• Wheel Diameter (D): 14 mm to 200 mm.
• Wheel Width (T): 13 mm to 50 mm.
• Mounting Height (H): 17 mm to 250 mm.
• Approximate Load Capacity: 25 kg to 1,200 kg.
• Static Load Capacity: 50 kg to 2,000 kg.
• Fixing Type: Rectangular Plate; Rectangular Plate, EN R42, 105 x 85 mm; Rectangular Plate, EN R43, 137 x 105 mm.
• Plate Dimensions (AxB): 30 x 17 mm to 140 x 115 mm.
• Plate Fixing Hole Centres (ExG): 45 x 45 mm to 105 x 80 mm.
• Fixing Hole Diameter: 4 mm to 11 mm.

Every fixed castor in the range fixes through a top plate, so there are no bolt hole or threaded stem versions, and none carry a brake, since braking is handled by the swivel castors. The compact 14 mm to 45 mm castors use small rectangular plates, while heavy-duty fixed castors rated at 500 kg or more all fix through the EN R43 plate. Most share their mounting height and plate with a matching swivel castor, so the two can be combined on one frame without packing or redrilling.

If the equipment needs to turn on the spot rather than track straight, why not browse Accu's Swivel Castors instead, as four swivel castors trade straight-line stability for full manoeuvrability.

FAQ

Q: Can you use four fixed castors on a trolley?

A: Yes, but only on equipment that moves forwards and backwards along a single line, such as a cart running between two stations or a frame on a test bench. With no swivel castors the trolley cannot be steered, so turning it means lifting or dragging one end, which scuffs floors and strains the castors. For anything that has to turn, the usual layout is two fixed castors at one end and two swivel castors at the other.

Q: Are fixed castors stronger than swivel castors?

A: Not necessarily. In Accu's range, a fixed castor almost always carries the same load rating, mounting height and plate as the matching swivel castor with the same wheel, because the wheel and its bearing set the limit rather than the swivel head. Where a fixed castor does help is durability: with no swivel head there is one less bearing to wear, and the rigid fork has no play to develop under repeated sideways loads.

Q: How many fixed castors does a trolley need?

A: Most four-castor trolleys use two fixed castors and two swivel castors, with the fixed pair at the end furthest from the handle so the trolley tracks straight while the operator steers. Longer platforms often run on six castors, with a fixed pair at the centre and swivel castors at each corner, letting the platform pivot around its middle; in that layout the centre pair carries a larger share of the load and is usually a size larger. Equipment that only ever moves in a straight line needs no swivel castors at all.

Bespoke Fixed Castors Manufacture.

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