Four swivel
All four castors turn, so the equipment moves in any direction.
Castor basics
Every part
has a name.
The parts, movements and measurements we ask about, in plain words, and the signs that a wheel needs replacing. The terms match our wheel guide.
Castor, wheel
or bracket?
A castor is a wheel held in a bracket that fixes to your equipment. We can supply the complete castor, or just the wheel or the bracket.
BracketWheelComplete castor
- Complete castor
- The wheel and the bracket together, ready to fit.
- Wheel only
- Just the wheel, for a castor, pallet truck or machine.
- Bracket only
- The fork and mounting, without a wheel.
Every part
has a role.
Plate, swivel head, fork, wheel and axle. Each part shapes how your equipment moves.
- Kingpin rivetHolds the swivel head together.
- Top plateBolts the castor to your equipment.
- Steel ballsA double ball race lets the head turn.
- Swivel headTurns with the fork as you steer.
- Dust coverKeeps grit out of the raceway.
- ForkHolds the wheel on its axle.
- Brake pedalHolds the equipment in position.
- WheelTread and centre, chosen for your floor.
- Ball bearingsLet the wheel roll freely.
- Thread guardsKeep threads and debris clear.
- Axle bolt & lock nutSecure the wheel in the fork.
Swivel, fixed
and brakes.
How a castor moves, and how it holds the equipment still.
FixedSwivel
Total lockWheel brakeDirectional lock
- Swivel
- Turns in any direction, so the equipment can steer.
- Fixed
- Runs in a straight line and keeps the equipment tracking.
- Total lock
- Locks the wheel and the swivel.
- Wheel brake
- Stops the wheel turning.
- Directional lock
- Holds a swivel castor straight.
- Other types
- Twin wheel, shock-absorbing, levelling foot, scaffold and low profile castors build on the same parts.
The wheel.
Its size, its tread and the way it turns on the axle. Tread materials differ in feel and colour; we’ll help you choose the exact compound.
DiameterTread width, hub and bore
- Wheel diameter
- Straight across the wheel, including the tyre.
- Tread width
- Across the tyre only. Leave out the hub and bracket.
- Tread
- The outer layer that meets the floor.
- Wheel centre
- The core the tread sits on.
- Bore (axle hole)
- The hole the axle passes through.
- Hub length
- The centre section that sits between the bracket legs.
- Bearing
- How the wheel turns on its axle: a ball bearing, roller bearing or plain bore.
The measurements.
Measure what you can. A photo with a tape measure alongside helps too, and any size you don’t know can stay unknown in your brief.
Overall heightSwivel offset
Swivel radiusSeen from above
Plate sizeHole centres
Top plateBolt holeStem
- Overall height
- From the floor to the top of the plate, or to the base of the stem.
- Swivel offset
- Seen from the side, how far the axle sits behind the centre of the swivel.
- Swivel radius
- The room a swivel castor needs to turn a full circle: from the centre of the swivel to the far edge of the wheel.
- Plate size
- The length and width of the top plate.
- Hole centres
- From the middle of one hole to the middle of the next, along each side of the plate.
- Bolt-hole diameter
- The size of each plate hole, or of the single hole for a centre bolt.
- Threaded stem
- Screws into a nut or socket. Note the thread size, such as M12, and the stem length.
- Plain stem
- Pushes into a tube or socket. Note the stem diameter and length.
Wheel layouts.
Seen from above. The layout shows which castors steer, which keep the equipment running straight and how many wheels carry it.
Two swivel, two fixed
Steers from one end, while the fixed pair keeps it running straight.
Six wheels
Four swivel at the corners and two fixed in the middle.
Diamond
Two fixed in the middle and a swivel at each end.
Three swivel
Three swivel castors on a round or three-point base.
When to replace
a wheel.
Look for these signs. If you notice one, send us a photo of the wheel, its mounting and any markings.
Flat spots
The tread has flattened where it stood or skidded, so the wheel thumps as it rolls.
Cracks or a loose tread
Splits, missing pieces, or a tread coming away from the wheel centre.
Marks on the floor
Dark streaks, or grit and chips pressed into the tread.
Noisy or hard to push
Grinding or squeaking, a wheel or swivel that turns stiffly, or thread wound around the axle.
Wobble or play
The wheel leans or rattles in the fork, or the swivel head has worked loose.
A brake that slips
The equipment creeps with the brake on, or the pedal no longer locks.
Next step