This FAQ helps you choose the right industrial castors and wheels for trolleys, machinery, warehouse equipment, food production, outdoor use and replacement applications. For advice on load capacity, wheel material, fixing type or floor suitability, contact Keystone Castors for technical support.
Not sure which castor or wheel you need? Contact us and send us what you know, even if some details are missing. We’ll use that to recommend suitable options and will only contact you if we need to clarify your requirements.
General Questions
What is the difference between a castor and a wheel?
A wheel is the rotating component that allows movement. A castor is the complete assembly, including the wheel, bracket and fixing method used to attach it to equipment, trolleys or furniture.
What are the main types of castors?
- Swivel Castors – Rotate 360° for easy manoeuvrability
- Fixed (Rigid) Castors – Provide straight-line movement and directional stability
- Braked Castors – Include wheel or swivel locking mechanisms
- Directional Lock Castors – Switch between swivel and fixed movement when required
What wheel materials are castor wheels made from?
- Rubber – A good choice where quieter movement, vibration absorption and floor protection are important. Rubber wheels are often used on lighter-duty trolleys, institutional equipment and applications where noise reduction matters.
- Polyurethane (PU) – A popular industrial wheel material that combines good load capacity with floor protection and relatively low rolling resistance. Polyurethane wheels are often used in warehouses, factories, workshops and material handling applications.
- Nylon – A hard-wearing and economical material with low rolling resistance. Nylon wheels are suitable for smooth floors and higher load capacities, but they are noisier than softer tread wheels and provide less vibration absorption.
- Polypropylene – A lightweight, economical wheel material often used for general-purpose applications. Polypropylene wheels can work well on smooth floors and are resistant to many chemicals, but they provide limited cushioning and can be noisier than rubber or polyurethane.
- Cast Iron – A strong, durable material suitable for heavy-duty applications and harsh industrial environments. Cast iron wheels can carry high loads, but they are noisy, provide no vibration absorption and may damage delicate floor surfaces.
- Steel – Used for demanding industrial applications where strength, impact resistance and high load capacity are required. Steel wheels are very durable but are hard on floors and best suited to robust industrial surfaces.
- Phenolic Resin – A hard, durable material often used for high-temperature applications. Phenolic resin wheels can carry good loads and resist heat, but they are harder and noisier than softer tread wheels.
Each material offers different performance characteristics depending on load capacity, floor surface, noise level and working environment.
Need help choosing? Contact us and tell us your load, floor type, wheel diameter and fixing type, and we’ll recommend suitable options.
Selection & Sizing
How do I choose the right castor?
When selecting a castor or wheel, consider the following:
- Load capacity: Calculate the total weight of the equipment plus the maximum load it will carry. Always allow for uneven weight distribution.
- Floor conditions: Consider whether the castors will be used on smooth floors, concrete, tiles, uneven surfaces, thresholds or outdoor ground.
- Wheel diameter: Larger wheels are generally easier to push and perform better on uneven floors. Smaller wheels may be suitable where overall height needs to be kept low.
- Wheel material: Rubber, polyurethane, nylon, polypropylene, cast iron and steel wheels all perform differently depending on load, floor surface, noise and environment.
- Noise requirements: Softer tread wheels such as rubber and polyurethane are usually quieter than hard tread wheels such as nylon, polypropylene, cast iron or steel.
- Environmental conditions: Check whether the castors will be exposed to water, washdown, chemicals, oil, heat, cold, corrosion or outdoor conditions.
- Mounting type: Make sure the castor fitting matches the equipment. Common options include top plate, single bolt hole, threaded stem and expander fittings.
- Frequency of movement: Equipment moved regularly may need larger wheels, better bearings and lower rolling resistance. Equipment moved occasionally may prioritise load capacity and stability.
- Brakes or locks: Consider whether the equipment needs to be held safely in position using wheel brakes, total stop brakes or directional locks.
How do I calculate load capacity for a castor?
Standard 4 castor setup
- Each castor must support at least one-third (33%) of the total gross weight:
- Formula: (Transport Equipment Weight + Maximum Load) ÷ 3
Example: trolley weight 60kg + max. load 300kg = 360kg gross weight.
360 ÷ 3 = 120kg minimum load capacity per castor.
Light Load 3 castor setup (Light Loads Only)
Each castor must carry at least 40% of the total gross weight.
- This setup is suitable only for lightweight trolleys.
6 Castor Set Up (Central Fixed Castors)
This configuration features two central fixed castors that are slightly taller – either by size or with packing plates (typically 25mm extra height).
Used for long platform trolleys to enhance manoeuvrability and control.
- Central fixed castors: Must each support at least 50% of the gross weight
- Other castors: Should support at least 33% of the gross weight
See Load Capacity of Castors | Considerations | Keystone Castors for a more detailed explanation
What wheel diameter should I choose?
Larger wheels roll more easily and perform better on uneven surfaces. Smaller wheels are often used where overall equipment height must be kept low.
Need help choosing? Contact us and we’ll recommend suitable options.
How do I measure a replacement castor?
As a minimum, we need the following measurements to help identify a suitable replacement castor:
- Wheel diameter
- Tyre tread width
- Overall height
- Fixing type and fixing measurements:
- For top plate castors: plate length, plate width, bolt hole centres and bolt hole diameter
- For single bolt hole castors: bolt hole diameter, usually 10mm or 12mm
- For stem castors: thread size and stem length
Other measurements may also be relevant depending on the castor type and application. These are shown in the diagram below and can help us match the replacement more accurately.
Not sure which castor or wheel you need? Contact us and send us what you know, even if some details are missing. We’ll use that to recommend suitable options and will only contact you if we need to clarify your requirements.
Can castors be fitted to any trolley or equipment?
Many castors can be fitted to existing equipment provided the mounting type, fixing centres, load capacity and overall height are suitable.
Performance & Applications
What castor wheels are best for concrete floors?
Polyurethane and rubber tyre wheels are commonly recommended for concrete floors as they provide smoother movement, reduced vibration, and enhanced floor protection.
Nylon and polypropylene wheels are also often suitable and, thanks to their hard tread, offer very low rolling resistance, making them the easiest option to push. However, they provide minimal vibration dampening.
What castor wheels are best for protecting floors?
Soft Grey rubber and polyurethane wheels are ideal for protecting delicate floors, reducing marking and minimising noise.
What’s the difference between nylon, rubber and polyurethane wheels?
- Nylon Wheels – Hard-wearing with low rolling resistance
- Rubber Wheels – Quiet operation with good shock absorption (Choose grey rubber for non-marking)
- Polyurethane Wheels – Durable, floor-friendly and suitable for higher loads
Are there castors suitable for outdoor or wet environments?
Yes. Stainless steel and powder-coated castors are commonly used in outdoor, washdown and corrosive environments.
Zinc-plated castors provide cost-effective corrosion protection, as the zinc coating acts as a protective layer that wears away before the underlying steel. However, they are not as durable or long-lasting as Stainless Steel or Powder Coated finishes.
Why are my castors difficult to push?
Poor manoeuvrability can be caused by:
- Overloading
- Incorrect wheel material
- Small wheel diameter
- Damaged bearings
- Uneven floors
- Incorrect castor layout
What’s the difference between plain bore, roller bearing and ball bearing wheels?
The bearing type inside a castor wheel affects how easily the wheel rolls, how much weight it can carry, how well it performs at speed and how suitable it is for different working environments.
Plain Bore Wheels
Plain bore wheels do not contain a separate bearing. Instead, the wheel rotates directly around the axle or bore.
- Simple and economical design
- Suitable for lighter loads and occasional movement
- Low maintenance
- Can perform well in wet or washdown environments where bearings may corrode
- Higher rolling resistance compared with bearing wheels
Plain bore wheels are commonly used on lighter-duty equipment, institutional applications and equipment that is moved infrequently.
Roller Bearing Wheels
Roller bearing wheels use cylindrical rollers inside the wheel hub to reduce friction and improve load handling.
- Good load capacity
- Lower rolling resistance than plain bore wheels
- Suitable for medium and heavy-duty applications
- Perform well under higher loads and slower speeds
- Often used on industrial trolleys, warehouse equipment and handling applications
Roller bearings are a popular choice where equipment carries heavier loads but does not operate at high speeds.
Ball Bearing Wheels
Ball bearing wheels use precision ball races to provide smooth rolling performance and low friction.
- Very low rolling resistance
- Smooth and quiet operation
- Suitable for frequent movement and higher operating speeds
- Good manoeuvrability and reduced pushing effort
- Often used on equipment that is moved regularly
Ball bearing wheels are commonly used on warehouse trolleys, production equipment, transport equipment and applications where ease of movement is important.
Which Bearing Type Should I Choose?
As a general guide:
- Plain Bore: Best for lighter-duty or infrequently moved equipment.
- Roller Bearing: Good for heavier industrial loads and slower-speed applications.
- Ball Bearing: Best for smoother rolling, frequent movement and reduced pushing effort.
The best bearing type depends on the load, movement frequency, floor conditions, environment and operating speed.
Maintenance & Replacement
Can I replace just the wheel?
Yes. Replacement wheels can often be fitted provided the wheel diameter, hub width (the distance through the centre bore/hole) and bore size match the existing assembly:
- A = Wheel Diameter
- B = Tread Width
- C = Bore Size
- D = Hub Width
How should castors be maintained?
- Inspect for wear or damage
- Remove debris from wheels and bearings
- Lubricate moving parts where required
- Tighten loose fixings
Brakes & Special Features
What is a braked castor?
A braked castor includes a locking mechanism designed to prevent unwanted movement when equipment is stationary.
What is the difference between a wheel brake and a total stop brake?
A wheel brake stops the wheel rotating but still allows the castor to swivel. A total stop brake locks both the wheel and swivel movement.
Are custom castor solutions available?
Yes. Keystone can often provide customised solutions including:
- Wheel material selection
- Special mounting options
- Brake configurations
- High-temperature wheels
- Heavy-duty solutions
- Stainless steel assemblies
Not sure which castor or wheel you need? Contact us and send us what you know, even if some details are missing. We’ll use that to recommend suitable options and will only contact you if we need to clarify your requirements.
