A caster configuration decides how a piece of equipment moves. Rigid casters hold a fixed direction, swivel casters steer, and swivel-with-brake casters do both and can lock in place. Most four-wheel industrial equipment uses two rigid and two swivel casters — not four swivel casters, which is the most common specification mistake.
This guide explains what each configuration actually does, how to decide the mix, and the brake details that are usually left out of an enquiry.
What each configuration does
Rigid casters
A rigid caster has a fixed bracket. It rolls in one direction and cannot steer. Rigid casters are not simply "the cheap option" — they are the steering reference for the equipment. On a four-wheel cart, the rigid pair defines the direction of travel and keeps the unit tracking straight when pushed.
Rigid casters are normally mounted on the side of the equipment that carries more of the load and does not need to turn.
Swivel casters
A swivel caster has a rotating bracket that allows 360-degree steering. The swivel radius — the horizontal offset between the vertical load line and the wheel axle — is what lets the wheel trail behind the load and self-align while rolling.
Swivel casters need clearance around them. If a swivel caster is mounted too close to a frame member, a guard or another component, the bracket will hit it before completing a full turn. This is a mounting check, not a load check, and it is missed more often than any other dimension.
Swivel casters with brake
A braked caster combines steering with a locking mechanism. The critical detail: "brake" alone is ambiguous. There are three different functions sold under that word, and they solve different problems.
The four-caster mistake: why not all swivel?
Buyers often assume that more swivel means more manoeuvrability. On equipment that is pushed or towed in a straight line, four swivel casters produce yaw — the unit wanders left and right and the operator has to correct continuously. On a long or heavy cart this becomes tiring and, on ramps or inclines, unsafe.
The standard arrangement on four-wheel industrial equipment is two rigid casters plus two swivel casters. The rigid pair holds the line; the swivel pair takes the turns. This gives controlled steering with less effort and a lower total cost than four swivel casters.
When four swivel casters are the right answer
- Equipment that has to move sideways or rotate on the spot in a confined area, such as between racking or in a lift
- Short-travel, light-load trolleys where straight-line tracking does not matter
- Applications where the frame geometry cannot accommodate a fixed direction
Outside those cases, four swivel casters usually add cost and reduce control rather than increase flexibility.
Pushed or towed: why the movement mode changes the answer
The same equipment can require different caster configurations depending on how it is moved. A hand-pushed cart and a towed trailer of the same weight are not specified the same way.
Hand-pushed equipment relies on the rigid pair to keep it tracking. The operator supplies the steering input through the swivel end. Towed equipment — a trailer, a luggage train, a towed platform — needs a lead caster arrangement that follows the towing direction without the operator correcting it. If a towed unit is fitted with swivel casters on the leading end, it can track unpredictably at speed and may swing out on a turn.
Powered and automated equipment (AGV, AMR, powered tugs) is different again. Here the drive or guidance system supplies direction, so swivel casters can be used more freely, often at every position. The caster requirement shifts from "which end steers" to "how much lateral freedom does the guidance system allow".
Before choosing a configuration, state how the equipment moves. It changes the answer more than most buyers expect.
How to decide the mix
Three questions settle most configurations:
- Does the equipment travel mainly in a straight line, or does it need multi-directional movement? Straight-line and towed applications point to a rigid pair; confined-space handling may justify full swivel.
- Is there a ramp, incline, conveyor transfer or dock plate? Any slope changes the requirement — casters on an incline can roll away, so the brake function and the position of the braked casters both matter.
- Does the equipment have to stay put while loaded? If it does, at least two of the casters need a locking function, and the pedal has to be reachable after the equipment is loaded.
On equipment with an uneven load distribution, the number of casters is not the same as an even load split. A four-caster unit does not divide its total load equally across four wheels — the centre of gravity shifts with the load, and one or two casters can carry significantly more than the others. This is why a catalogue figure expressed as a four-wheel set rating is not a per-wheel figure and should not be divided by four.
Brakes: the detail most enquiries leave out
There are three functions sold as "brake", and they are not interchangeable:
| Function | What it locks | What it solves |
|---|---|---|
| Wheel brake | Stops the wheel from rolling | Prevents movement on a level or slight slope |
| Swivel lock | Stops the bracket from rotating | Converts a swivel caster into a fixed-direction caster for straight-line pushing |
| Total lock (double brake) | Locks wheel and swivel together | Holds both position and direction, typically needed on ramps |
When a specification says only "with brake", confirm which of the three is required. A wheel brake on a swivel caster still allows the unit to rotate on the spot. On an incline, that is the difference between holding and drifting.
Pedal access
A brake pedal is only useful if the operator can reach it with the equipment loaded. Check pedal height, the direction it operates in, and whether the frame, a guard or the load itself blocks access in the installed position. A pedal visible in a product photo does not confirm that it stays reachable on your equipment.
Common specification mistakes
- Choosing four swivel casters for "flexibility". It usually produces wandering in straight-line travel and costs more.
- Assuming the load splits evenly across four casters. Centre-of-gravity offset means individual casters can be loaded well above the average.
- Treating "brake" as one thing. Wheel brake, swivel lock and total lock solve different problems.
- Checking wheel diameter but not mounting height. A larger wheel changes obstacle clearance, but it also raises the deck and can change the turning geometry.
- Fitting only one braked caster. A single locked caster on a four-wheel unit still allows the frame to pivot around it.
What to send with a caster enquiry
To get a usable quotation rather than a price range, include:
- Equipment type and how it moves (manual, towed, powered), plus travel speed and distance
- Total weight including payload, and the number of casters
- Required quantities of rigid, swivel and swivel-with-brake casters
- Which locking function is needed — wheel, swivel, or both
- Mounting dimensions: top plate and hole centres, or stem diameter and length
- Floor type and condition, temperature, cleaning chemicals, and any noise or floor-marking limit
- Sample or bulk quantity, destination country or port
If you have an equipment drawing, send it. Mounting dimensions on the drawing are more reliable than measurements taken from the old caster after it has worn.
Start with the caster range, then confirm the configuration
KORONO publishes 28 industrial caster series across light duty, heavy duty, integral wheel and shock-absorbing ranges, in 75 to 200 mm wheel diameters, with top-plate or bolt-hole stem mounting. Each series page lists the mounting dimensions and available configurations for that range.
Two useful next steps:
- Compare the ranges on the full caster catalogue, or start with heavy duty casters for equipment and material-handling applications.
- Read the seven-step caster selection guide if you are still establishing the load and mounting requirements.
When the configuration is defined, send the specification for a quotation. Include the rigid, swivel and brake quantities separately so the exact models can be confirmed against your equipment.
Related guide: Read why a four-wheel caster load should not be divided by four before selecting the caster configuration.