Castors & wheels
come in various shapes, sizes and loading capacities. It’s important you choose wisely and factors such as the floor surface, application and loading weight to be carried must be taken into consideration. If you choose the wrong type of castor or wheel you may cause damage the surface on which it’s used, the load being carried and at worst be unable to operate the trolley safely - putting either you or your employees at risk.
There’s a lot to consider - the max load, type of castor, fixings, bearings, brakes and steering. Confused about where to begin?
These are the main things you need to consider when choosing industrial castors and trolley wheels...
Working out the max potential load of your trolley
This is the most important step when choosing any type of castor or wheel you need as failing to do so may mean not being able to operate your trolley safely. First thing you’ll need to do is work out the maximum potential load that your trolley will need to take (don’t forget to add the weight of the trolley to this). This is sometimes referred to as the working load limit (WWL) or safe working load (SWL)
Once established you can now work out the individual load capacity you will require for each wheel on your trolley device.
Divide the total weight by three to give a guide as to the loading capacity required for each castor to be fitted to the trolley.
For example, if you require a 4 wheel trolley to carry a maximum potential load of 400Kg and the trolley itself weighs 50Kg, each castor has to have a minimum loading capacity of :
400KG+50KG =150KG SWL per wheel or castor minimum 3
Which castor wheel diameter do I need?
The larger the wheel, the easier it will be to push over any uneven surface with minimum impact on the load on the trolley. For better safety and performance it’s best to go for the largest wheel practicable even if you think you need small trolley wheels.
What types of castor wheels are available?
You’ll need a different type of castor wheel depending on the application and surface.
● Rubber wheels
Ideal surface type: concrete timber, vinyl and tiled floors
Rubber wheels are generally un-marking, shock-absorbing and quiet. They are strong and durable wheels which are suitable for internal and external agricultural and horticultural applications.
● Polyurethane wheels
Ideal surface type: Floated concrete floors & tiled floor
Polyurethane is renowned as a very tough material. Wheels will consist of either entirely polyurethane or a combination of a polyurethane outer with a centre of metal or nylon. They are durable, long-lasting and have a shock-absorbing cushion between your products and the floor.
However, they’re not suited for high-temperature applications as the durability will be compromised greatly (they won’t withstand a heat of over 230 degrees)
● Nylon wheels
Ideal surface type: hard, smooth surfaces and outside/wet environments
Nylon wheels have been used for decades in industrial applications and specifically materials handling. The wheels are generally non-marking, durable and have low rolling resistance. They are commonly used on smooth surfaces.
● Cast Iron wheels
Ideal surface type: heavy-duty industrial environments
These are the ultimate heavy-duty castor wheels. Cast iron wheels are ideal for industrial environments as they have very high load capacity. They can also deal with extreme temperatures (-30 to 300 degrees) where no tyre is used
● Aluminium wheels
Ideal surface type: use in bakery ovens, smokehouses, chillers and other environments with extreme temperatures
Aluminium are also a good wheel for industrial and extreme-temp environments. However, it’s worth noting that they have a slightly lower weight capacity to cast iron wheels.
What fixing type will I need?
There are two main fixing types which you’ll need to choose between:
1. Bolt Hole
With this fixing, an internal thread is pushed through the bolt hole of a swivel head and screwed into a central bracket that attaches to the equipment to be moved. The stems can come in a variety of ways: expanding pintles, standard pintle bolt (in various sizes), threaded tube inserts or grip necks and friction stems (made for narrow tubes).
2. Plate Type
If your load is heavy and has a flat bottom, these are the most supportive fittings which can be welded or bolted to the product. Plate fixings come in a range of standard sizes making it easy for matching replacements.
What’s the difference between swivel and fixed castors?
- Swivel castors
Swivel castors allow for steering and offer great manoeuvrability of your trolley. This is because they can rotate a full 360 degrees and can deal with quick changes in direction.
- Fixed castors
A fixed castor is a wheel which is mounted in a bracket with a fixed direction. These wheels can’t be steered, but can move loads in a straight lines, back and forward.
Both Swivel and Fixed?
Swivel & fixed castors are often used in combination to allow for a trolley to be moved easily and with a greater degree of controllability
You could opt to have a combination of both swivel and rigid casters - especially when you want the ability to both change direction and move back and forth smoothly. This is possible by having one type on each end of the trolley. Typical examples being shopping trolleys in supermarkets.
- Which bearing do I need?
Different bearings allow a trolley to move easily from a standing start. This is important particularly as loads become heavier
Bearings are a mechanical component of the wheel which allows trolley movement and reduces friction between parts. Instead of two smooth surfaces sliding past each other, causing friction, bearings support the movement and reduce friction for less wear on the parts over time.
There are various types of bearings, but the main ones are:
● Plain: these are generally a simple tube that the axle of the wheel rotates upon are ideal for lighter loads or where high temperatures or corrosive environments are involved.
● Roller or Needle bearings: made to withstand high-impact, reduce roll resistance and can be used for heavy-duty applications.
● Ball bearings: the most popular type and are used where heat can build and cause friction.
Will I need brakes on the wheels?
Brakes are a common additional feature that are generally added to the swivel castor on any trolley. They are foot operated and work by applying a spring-loaded ‘chock’ to the wheel surface preventing it from turning.
Not always necessary, but should be considered if the surface which you are using your trolley is uneven or sloping
If you need castors for your trolley, or would like advice on which to choose, then contact us today
- we’d be happy to help.