Castors in the workplace
The choice of castor has many influencing factors to consider
Factors that have an influence are:
tyre or no tyre
pressed steel or fabricated construction
fixings plate. bolt hole, tube end
type swivel, fixed, total stop brake, wheel brake, directional lock
factors to consider are:
required carrying capacity
floor surface to be used on
required ease of manoeuvrability
Our standard range covers three wheel material types
The most popular material for the wheel is nylon, this is due to the fact that nylon is strong and resilient and also has a degree of self-lubrication, so is good as a plain bearing this means that you can often buy a more economic plain bearing wheel in nylon, where other materials would need a bearing to give the low roll resistance required for easy movement.
For light duty castors, untyred polypropylene wheels can give an economic alternative, but these are only suitable up to a capacity of 75kg per castor.
When fitted with a tyre, polypropylene wheeled castors can be suitable for greater load bearing capacities - up to 200kg castor capacity with rubber or polyurethane tyre.
Cast iron wheels
Castors with cast iron wheels have the capacity to carry much heavier loads load capacities up to 1100kg in our range with yellow polyurethane tyres
Tyred or untyred?
There are a number of factors to consider when choosing to have a tyred or untyred castor.
Untyred castor wheels are more economic
Untyred castor wheels are most suitable for use on a good, hard floor surface
If the end product is to be used on a poor floor surface or a soft floor surface it would be advisable to consider a tyred castor wheel.
Untyred wheels tend to be more noisy in use, which may be a factor to consider in your choice.
Castor tyres in our popular range come in two materials: rubber and polyurethane
Rubber tyred castors
Generally, rubber tyres are softer, but can still be used for carrying capacities of up to 400kg,
Black rubber tyred castors are extremely popular for many uses, but on clean floor surfaces, they can leave marks.
If marking of floor surfaces is a problem, then your choice would be better catered for by the other coloured rubber tyres either grey or blue.
Smart grey rubber tyred castors are frequently chosen when a non-marking tyre is required in an office or other location where a smart appearance is required.
Grey rubber tyred castors in our popular range are concentrated on the lower carrying capacity range up to 100kg per castor.
Blue rubber tyred castors in our range, however, are fitted to castors with load carrying capacities of up to 450kg
Polyurethane tyred castors
Polyurethane tyres are harder and suitable for castors with carrying capacities up to 1100kg.
Red polyurethane tyres in our popular range are fitted to polypropylene, nylon and cast iron wheels, whereas yellow polyurethane tyres are only fitted to the cast iron ‘G’ range
Carrying capacity / castor capacity
Each castor has a specified maximum load capacity. When choosing the required capacity you need to design in a safety factor.
To calculate the required load-bearing capacity of each castor, first decide upon the total capacity required by the end product that the castors are to be fitted to (truck, trolley etc)
Assuming that the product will be fitted with four castors, the recognised safety margin is achieved by dividing the total required capacity by three to determine the capacity for each castor
eg: For a total load of 600kg, you would select an individual castor capacity of at least 200kg (600 divided by 3)
If the castors are to be used on very uneven floor surface, it would be wise to increase the safety factor even further.
Our popular range of castors include castors with plain bore, roller, or ball bearings, the choice will depend on the use.
The purpose of a bearing is to reduce the resistance to movement (roll-resistance) and to increase the life by reducing potential wear bearings do not increase the load bearing capacity, but they do reduce the roll resistance, and therefore improve mobility.
Castors without bearings are used mainly for the lighter duty work, as the weight of the load increases, so the resistance to movement increases, which is when the use of a bearing can help
The most common bearing used on our popular castor range is the roller bearing. These are used on castors from 100kg capacity and above and improve the mobility due to the reduced roll resistance.
Ball bearings reduce the roll resistance still further, and would be chosen when longer distance and high frequency of use would benefit from this improved mobility.
The use of castors with bearings has an affect on the cost, and this has to be weighed against the improved mobility.
In general, items that simply need to be moved occasionally (eg a cupboard that may be moved from one location to another or moved for cleaning purposes) are more suitable for plain bore castors, whereas products that are designed for transporting other items (eg trolleys and trucks) would benefit from the use of castors with bearings.
The choice of wheel size used on castors is influenced by the floor surface and the roll resistance required in general, the larger the wheel diameter, the greater the wheel leverage (axle to edge distance), and therefore the easier it is to move (lower roll resistance). Also small wheels are best suited to good condition hard floors. Any unevenness in the floor surface would make transport harder for small diameter wheels, so the more uneven the floor surface, the greater the wheel diameter that might chosen.
Pressed steel or fabricated construction
The majority of our popular castor range is of pressed steel construction, although ranges ‘F’ and ‘G’ are of fabricated steel construction.
All our popular castors range have plate fixing, and many have option for bolt hole fixing which, with the addition of expanders, are suitable for tube end fixing situations.
Plate fixing castors are suitable where a flat surface is available that can take the fixings as shown on the individual castor details pages
Bolt hole fixing
Bolt hole fixing castors would be suitable where there is a single fixing hole required, and where there is not sufficient flat area for a plate fixing castor.
When a castor is to be fitted to the end of a tube, then you need a combination of a bolt hole fixing castor with an expander. The expander fits inside the tube and expands to hold the castor firmly in place when the bolt is tightened.
There are different expanders for either square or round tube, and each is available for a range of tube sizes.
For your convenience, we have provided a full range of expander options on each detailed page of bolt hole fixing castors, so a single order will include both the castor and the expander.
If you require expanders without castors, these can still be purchased separately.
All the castors in our popular castor range are available as swivel castors
They are fitted with double ball race swivel heads.
Many of the castors are also available as fixed castors, allowing two-directional movement.
A common combination for trolleys and trucks is to have two swivel and two fixed castors.
Total stop brakes
The most common form of brake is the total stop brake, which simultaneously locks both the wheel rotation and the swivel mechanism
On some ranges there is an option for a wheel brake only, which prevents directional movement, but still allows the swivel mechanism to operate.
An additional directional lock is available on our ‘F’ range of castors, this prevents the swivel action from operating, but allows the wheel to rotate