Choosing the Right Castors
The right castor comes down to six things: how much weight it carries, the floor it rolls on, the wheel size, whether it swivels or brakes, the environment, and how it mounts. Get those right and your trolley, bench or bin will roll easily, last longer and stay safe to use.
This guide walks through each step, with links to the matching products. If you're still unsure at the end, call us on (02) 9912 5120 and we'll help you pick.
Quick-start checklist
Answer these five questions before you shop:
- What's the total weight? Add the weight of the equipment to the heaviest load it will ever carry.
- What floor will it roll on? Smooth concrete, epoxy, tiles, timber, carpet, or outdoors on asphalt or gravel?
- Will it face water, chemicals, heat or cold? Washdowns, cool rooms, ovens and outdoor weather all change the choice.
- How does it need to move? Long straight runs, tight corners, or parked in one spot most of the time?
- How will it attach? A flat surface to bolt a plate to, a single bolt hole, or a hollow tube leg?
Then work through the steps below.
Step 1: Work out the load capacity you need
Divide the total loaded weight by 3, not 4, then add a safety margin. That's the minimum rating each castor needs.
Why divide by 3? Floors are never perfectly flat. When a trolley rolls over a crack, a door threshold or a dip, one castor can briefly lift off the ground and the other three carry the whole load. Sizing for three castors means you're covered when that happens.
Why add a margin? Load ratings are tested in ideal conditions: a smooth level floor, walking pace and an evenly spread load. Real use is rarely that kind. Add about 25% for normal indoor use, and more for outdoor work, rough floors, bumps or uneven loads.
The formula: (equipment weight + maximum load) ÷ 3 × 1.25 = minimum rating per castor
Worked examples
| Application | Total weight | ÷ 3 | + 25% margin | A castor that fits |
|---|---|---|---|---|
| Workbench (60 kg) with tools (90 kg) | 150 kg | 50 kg | 63 kg | 80 kg rated 100 mm nylon castors |
| Workshop trolley (100 kg) with stock (500 kg) | 600 kg | 200 kg | 250 kg | 270 kg rated 100 mm urethane castors |
Common mistake: buying castors that only just meet the total weight divided by four. They may work at first, but they wear quickly, get hard to push and can fail under a shock load.
Browse by capacity: Light Duty · Medium Duty · Heavy Duty · Extra Heavy Duty
Step 2: Match the wheel material to your floor
The floor decides the wheel. A wheel that's perfect on smooth concrete can be noisy on tiles, hard to push on carpet, or damage a timber floor.
| Wheel material | Best floors | Noise | Floor protection | Rolling effort | Watch out for |
|---|---|---|---|---|---|
| Rubber (grey or blue elastic) | Tiles, timber, vinyl, smooth concrete | Very quiet | Excellent, non-marking | Moderate | Not ideal with oils or high heat; harder to push under heavy loads |
| Polyurethane (PU) | Most indoor floors, epoxy, concrete | Quiet | Very good | Easy | The best all-rounder for trolleys and workshop equipment |
| Nylon | Smooth hard floors, wet or chemical areas | Noisy | Fair, can scratch soft floors | Very easy | Can slip on wet smooth floors and rattles over rough ground |
| Cast iron | Rough concrete, factories, very heavy loads | Loud | Poor, can damage floors | Easy on concrete | Use only where floor damage doesn't matter |
| Pneumatic (air-filled) | Outdoors: grass, gravel, uneven ground | Quiet | Good | Easy over bumps | Lower capacity and can puncture |
If in doubt, choose polyurethane. It handles most floors, runs quietly and carries heavy loads. Our red urethane castors go from 100 kg to 450 kg per castor.
Shop by material: Wheels · Medium Duty (rubber, PU, nylon) · Heavy Duty (PU, solid rubber, pneumatic)
Step 3: Choose the wheel size
Bigger wheels are easier to push. They roll over cracks, cables, expansion joints and door thresholds that would stop a small wheel, and they need less force to get moving.
This matters for safety as well as convenience. WorkSafe Victoria lists small-diameter castors as a hazard that increases pushing force, and larger-diameter castors as a way to reduce it.
| Wheel size | Typical use |
|---|---|
| 50 mm (2") | Furniture, display stands, light carts, low-profile machinery skates |
| 75–80 mm (3") | Light trolleys, shelving, workbenches on smooth floors |
| 100–125 mm (4–5") | General trolleys, tool chests, workshop equipment |
| 150 mm (6") | Heavy trolleys, 660 L and 1100 L bins, rougher floors |
| 200 mm (8") and up | Outdoor use, uneven ground, very heavy loads |
Two things to check before you size up:
- Overall height. A bigger wheel raises your equipment. Measure the clearance you have, especially under benches and machines.
- Rough or outdoor ground. As a rule of thumb, go bigger whenever the bumps you'll roll over are more than about 5% of the wheel diameter (5 mm for a 100 mm wheel).
Step 4: Swivel, fixed or braked?
Most equipment uses a mix. Swivel castors turn 360° for steering; fixed castors roll in a straight line for stability; braked castors lock in place.
| Layout | How it handles | Best for |
|---|---|---|
| 2 swivel + 2 fixed | Steers like a shopping trolley; tracks straight on long runs | Warehouse and platform trolleys, bin carts, long corridors |
| 4 swivel | Moves in any direction; harder to keep straight | Tight spaces, workbenches, furniture, kitchen equipment |
| 4 swivel, 2 with brakes | Manoeuvrable, and stays put when parked | Workbenches, tool chests, anything you work on while it's parked |
Where to put the brakes. Fit brakes on the swivel castors, at the end you push from, so you can reach them with your foot. For anything you load or work on, brakes are worth having. WorkSafe Victoria recommends lockable wheels to stop trolleys moving during loading and unloading.
Push, don't pull. Put the swivel castors at the end the operator pushes from. Pulling a trolley backwards risks running over your own feet and you can't see where you're going.
Shop ready-made sets: Castor Sets, with free shipping. Many sets come as two swivel with brake plus two fixed, or four swivel with two braked.
Step 5: Think about the environment
Water, chemicals, heat and cold wear castors out faster than weight does. Match the frame and wheel to where the castor will live.
| Environment | What to choose | Why |
|---|---|---|
| Commercial kitchens, food processing, washdown areas | Stainless steel frame with a nylon or PU wheel | Won't rust with regular cleaning and sanitising |
| Cool rooms and freezers | Stainless steel, or a castor rated for low temperatures | Standard rubber can harden in the cold |
| Ovens, bakeries, heat-treatment areas | High-temperature castors | Ordinary wheels soften or melt near heat |
| Chemical or oily areas | Nylon wheels | Resists most oils and chemicals |
| Outdoors | Pneumatic or large solid-rubber wheels, zinc-plated or stainless frames | Handles uneven ground and weather |
Our stainless steel range runs from 40 kg rated 50 mm castors up to 350 kg rated 150 mm castors. It also includes a 180 kg rated monolithic castor that handles −30 °C to +300 °C, for freezers and ovens alike.
Food businesses: Australia's Food Safety Standard 3.2.3 requires premises and equipment to be easy to clean and sanitise (see FSANZ's Safe Food Australia guide). Putting benches, racks and appliances on castors lets staff roll them out and clean underneath.
Step 6: Choose how the castor mounts
The mount has to suit what you're attaching it to. There are four common types.
| Mount type | What it is | Best for | What to measure |
|---|---|---|---|
| Top plate | A flat plate with four bolt holes | Trolleys, benches, bins, anything with a flat base | Plate size, and the distance between hole centres both ways |
| Bolt hole | A single hole through the centre of the castor (e.g. M10 or M12) | Furniture, shelving, frames with a single fixing point | Bolt diameter and thread |
| Stem or pintle | A threaded stem on top of the castor (e.g. M16) | Low-profile machinery castors, equipment with threaded sockets | Stem diameter, thread and length |
| Tube insert | A threaded insert that fits inside a hollow tube leg | Square or round tube frames, steel benches, racking | Inside size of the tube and the thread you need |
Replacing a castor? Measure the old one before you order: plate size, hole centres, bolt or stem size, wheel diameter, and overall height from the floor to the top of the plate. Matching the overall height keeps your equipment level.
No good mounting surface? A castor base plate gives you a flat surface to mount to.
Castors by application
Short on time? Start with the application closest to yours.
Trolleys and carts
Polyurethane wheels at 100–125 mm suit most indoor trolleys. Use two swivel castors with brakes and two fixed for steering and stability. Keep castors clean and replace worn ones early, as damaged castors make trolleys much harder to push. WorkSafe Victoria's trolley guidance is a good checklist for workplaces.
Shop: Castor Sets
Workbenches and tool chests
Use four swivel castors with at least two braked, so the bench stays put while you work. PU or rubber wheels protect garage and workshop floors. Check the overall height so the bench ends up at a comfortable working level.
Shop: Medium Duty Castors
Waste bins (660 L and 1100 L)
Large bins carry serious weight. The City of Fremantle's waste guidelines list typical weights of 265 kg for a 660 L bin and 440 kg for an 1100 L bin. Use 150 mm bin castors: cast iron for toughness, or urethane for quieter rolling near homes and businesses.
Shop: Waste Bin Castors
Commercial kitchens and food processing
Stainless steel frames with nylon or PU wheels handle daily washdowns. Choose braked castors for benches and appliances that need to stay put during service.
Shop: Stainless Steel Castors
Furniture and DIY projects
For planter boxes, shelving, display stands and furniture, 50–75 mm rubber or nylon castors are usually enough. Bolt hole castors suit furniture with a single fixing point.
Shop: Light Duty Castors · Bolt Hole Castors
Gates
Spring-loaded gate castors take the weight off gate hinges and absorb bumps on uneven driveways. We stock 50 mm and 100 mm rubber-wheel versions.
Shop: Light Duty Castors
Machinery and very heavy loads
Low-profile castors keep heavy machines close to the floor; our 50 mm low-profile sets are rated to 1,200 kg. For machines that need to stay perfectly level once in place, use adjustable levelling feet.
Shop: Low Profile Castors · Extra Heavy Duty Castors
Frequently asked questions
What does the load rating on a castor set mean?
A set's rating is the four castors' ratings added together. For example, a 600 kg set is four castors rated at 150 kg each. Because you should size for three castors (Step 1), that set safely carries about 450 kg of total weight, or around 360 kg once you allow a 25% margin.
Should all four castors swivel?
Only if you need to move in tight spaces. Four swivel castors are easy to manoeuvre but hard to push in a straight line. For trolleys travelling any distance, two swivel and two fixed is easier to control.
Will castors damage my floor?
They can if the wheel is too hard for the surface. Rubber and polyurethane wheels are gentle on tiles, timber and vinyl. Cast iron and nylon wheels can scratch or dent softer floors.
Why is my trolley so hard to push?
The most common causes are wheels too small for the floor, the wrong wheel material, worn or damaged castors, debris wrapped around the axle, or overloading. Upgrading to larger polyurethane wheels often makes the biggest difference.
Is it "castor" or "caster"?
Both are correct. "Castor" is the usual Australian and British spelling, and "caster" is the American spelling. They mean the same thing.
Can I mix different castors on one piece of equipment?
You can mix swivel, fixed and braked versions of the same castor. Avoid mixing wheel sizes or overall heights, because the equipment won't sit level and the load won't spread evenly.
How often should I check my castors?
Inspect them regularly for flat spots, cracks, loose bolts, wobbly swivels and debris around the wheel. Workplaces should include castors in their equipment maintenance schedule.
Still not sure? Talk to us
We've been helping Australian businesses and DIYers choose castors for over 15 years. Tell us what you're moving, how heavy it is and what floor it rolls on, and we'll recommend the right castor.
- Phone: (02) 9912 5120, 8am–4pm, Monday to Friday
- Email: sales@castorco.com.au
- Online: Contact us
Need something custom? We can help with non-standard sizes and applications too.
Free shipping on all castor sets and orders over $50 (no PO boxes). Shop all castors
Important: Load ratings assume use on a flat, even surface under normal conditions. Never exceed a castor's rated load, and inspect castors regularly for wear or damage. You are responsible for choosing castors suitable for your application. See our full Legal Disclaimer.