Factors to Consider When Choosing Wheels and Casters
IMPORTANT NOTICE
Where casters are used as a component of a product, place proper instructions on the product including the information provided by Mister Roller Inc.
CONDITIONS OF SALE AND DELIVERY
The sale is subject to standard conditions set forth on the back of our invoice. The following information is provided for general information purposes and is not intended to constitute representations or warranties. A deposit for large orders or for an order of custom casters will be required. Customer will be advised with a formal quotation. Custom made caster orders cannot be cancelled after order has been issued.

1. Type of tire
The choice of the tire along with the correct wheel or caster is crucially important. The caster should be chosen knowing the required load capacity, the application and environmental conditions.

2. Chemical resistance
The chemical resistance of tires depends on the temperature and period of contact with the medium. Contact for a short period of time usually does not have a negative effect. Solid rubber tires normally demonstrate good resistance to water, diluted bleach and acids. Topthane® usually demonstrates good chemical resistance to grease, oil, aliphatic hydrocarbons and many solvents. It is not resistant to hot water, steam, acids and some alkalines. On request a list of chemical resistance for tires is available.

3. Working Conditions

a) Storage
Tires should be stored in a dry, cool place and be protected from direct sun-light. Storage time should not exceed more than 2 years although polyamide wheels can be stored for a longer period under proper conditions.
b) Conditions of application
The quality of the tires as well as the wheel diameter are determined by the nature of the road surface. For example, it is preferable to choose a large wheel diameter with elastic tires for use on an uneven surface.

4. Load capacity
The load capacity for the wheel or caster may be determined as follows:
Gross weight (=weight for vehicle + load) divided by 3. (In general, only three of the four wheels are in contact with a rough surface). Moreover temporary overloading can occur (for example when obstacles are encountered). More severe conditions may require a higher margin of safety.

5. Rolling and start-up resistance
The rolling and start-up resistance are important factors for determining the power required for the movement of a vehicle. Resistance depends on the tires, temperature, floor surface and the total load. For example, on a smooth road surface and a wheel diameter of 200 mm:

8" diameter wheel
Nylon
Standard rubber
Elastic Rubber
Topthane®
Soft Topthane®
Starting resistance in %
1.4
4.6
1.4
1.4
1.4
Rolling resistance in %
0.6
3.4
0.9
0.7
0.6

6. Application and intensity of use
The choice of bearing depends on the conditions under which the wheel or caster is to be used and the intensity of use. Wheel bearings can be divided into the following groups:

Plain bearings
Simple, almost maintenance free bearing. Resistant to shocks. Suitable for use in wet conditions. For low speed vehicles.

 
Roller bearings
Sturdy, resistant, almost maintenance free bearing. Low friction bearing. Shock resistant. The bearing most often used on low speed vehicles.

 
Groove ball bearings (Precision ball bearings)
Roll well even at higher loads and speeds and are suitable for continuous use.
   
Tapered roller bearing
Used on heavy duty wheels. High load capacity. Variable movement.
7. Coefficient of friction
The coefficient of friction is important for powered or braked wheels. The coefficient of friction depends on various factors such as the type of surface, humidity, dust, grease, the tire material and so on. Experience has shown that the coefficient of friction vary according to changes in the various factors. For example, a Topthane® tire can rub a rolled steel surface or a rough concrete surface. The coefficient of friction indicates the relationship between horizontal force and vertical load. (example: 10 000 newton vertical load, tyre with m = 1 requires engine power of 10 000 newtons).
 
Elastic rubber
Topthane®
Dry Concrete
1.0
0.6
Wet Concrete
0.6
0.4
Dry Asphalt
0.5
0.4
Wet Asphalt
0.3
0.2 - 0.3
Dry Steel
0.7
0.2 - 0.4
Wet Steel
0.3
0.1 - 0.2
Grease / Ice
0.1 - 0.2
less than 0.1

8. Resilience
The degree to which tires retain their shape under loads is called resilience and contribute to the driving comfort. Factors include the hardness and thickness of the tire. The resilience diagram does not proceed linear but degressive. On a smooth and hard road surface, the resilience would be measured as follows (having wheel of 200 mm diameter and bearing a nominal load):

 
Polyamid
Standard rubber
Elastic rubber
Topthane®
Load ( Kg )
550
205
400
700
Resilience ( mm )
0.6
4.5
5.0
1.3
9. Pressure on the ground
The degree of contact on the ground depends on resilience. The load divided by the surface contact indicates the static pressure of a wheel to the ground.
Measured on a hard smooth surface with a wheel diameter of 200 mm, the pressure (N/mm2) amounts to:
 
Polyamid
Standard rubber
Elastic rubber
Topthane®
Load ( Kg )
550
205
400
700
Resilience ( mm )
50.3
1.5
1.4
8.7

10. User information
1.0 Product guide

Wheels and casters are components that are generally replaceable. They are installed on equipment, furniture, material handling systems or similar products to make these products mobile. This product guide refers to casters and wheels and particularly to swivel casters (not steered casters) which are used on non-powered equipment at a speed not to exceed normal walking speed and not being used continuously. Casters and wheels, according to this product guide, may be classified by the following categories:

Domestic Uses i.e. seating, furniture

-General

i.e. shopping carts,
office equipment

-Health care

i.e. beds, carts etc.
Industrial Uses i.e. material handling of all load capacities

Casters and wheels may have a long and trouble-free life provided the following guidelines are adhered to:
a) Correct and secure mounting at the proper locations.
b) The mounting location must have adequate strength and material for
stable installation.
c) The installation must not interfere with the operation of the product.
d) For swivel bearing king pin must be vertical at all times.
e) Rigid casters must be installed with their axles perpendicular to the
direction of travel.
f) If only swivel casters are used,all of them must be of similar type.
g) If rigid casters are used in conjunction with swivel casters, all casters
must be compatible and in accordance with the specifications recommended by the manufacturer.
Where casters are used outdoors, in coastal areas, in corrosive and/or aggressive environments, custom products will be required.
For use in temperatures below 5°C (40°F) and above 30°C (85°F), the
performance of the caster may be impaired and particularly its load bearing capacity may be affected. Custom products will be required.
Casters are made of component parts. The manufacturer is only liable for the original components incorporated in the assembled caster.
When selecting a caster, it is necessary to take into consideration the technical specifications for such caster.

2.0 Misuse
The following conditions are not acceptable when using casters:

2.1 Overloading
2.2 Unsuitable floor conditions
2.3 Excessive (high or low) temperatures
2.4 Failure to use brakes properly
2.5 Exposure to hostile environment
2.6 Excessive loads or shock
2.7 Foreign objects penetrating the wheel tread
2.8 Excessive speed
2.9 Changes made to components and to assembled casters without prior approval of the original manufacturer.

3.0 Maintenance Tips
The user is responsible for proper operation and maintenance of the casters and wheels. How often maintenance is to be done will be determined by how the product is used. To help you extend the use of our products, you should do the following:

• Regularly lubricate the axles and bearings.
• Periodically clean dirt and dust particles from the axle swivel and wheel bearings.
• Check for thread wear and replace worn casters.
• Verify that the swivel head and wheels turn freely and smoothly, otherwise change the casters.
• Verify that the casters are not bent.
• Verify that the welding is intact and not broken.
• Verify that the kingpin is fastened securely.
• Retightening the axle and/or any adjustable fittings.
• Use lock washers or lock nuts on all axles
• When cleaning casters and wheels, do not use cleaning agents that contain corrosive or granular ingredients.

4.0 Product-Information and User Guide
It is necessary to insure that the Product Information and User Guide are made available as required and that the reseller ensures that his customers are furnished with the appropriate catalogs, etc. The Original Equipment manufacturer on whose equipment the product is attached, must ensure the end user is provided the Product Information and User Guide. To ensure proper performance of the casters and wheels, the reseller must consider the Product Information.
 
FORBIDDEN

 

SWIVEL CASTER
WHEEL

Dimensions are approximate. They are subject to change without notice, particularly as a result of new designs or improvements.

 

 

 

CASTER ARRANGEMENT
4 Swivel
Four swivel casters mounted in a rectangular or square pattern. This arrangement offers maximum maneuverability and allows for directional change with little effort: it is ideal for use in confined areas.
2 Swivel / 2 Fixed
Two swivel and two fixed casters mounted in a rectangular or square pattern. Steers accurately and is pulled or pushed from the swivel caster end with a slight loss in overall maneuverability compared to the previous arrangement.

4 Swivel / 2 Fixed
Four swivel and two fixed casters mounted in a rectangular pattern with either all wheels equal or rocking on the two fixed center casters. Load capacity is dependent on the choice of arrangement. Trucks using this layout are very stable and maneuverable, with easily controlled steering and are able to negotiate ramps. Suitable for long or wide trucks.

2 Swivel / 2 Fixed
Two swivel and two fixed casters mounted in a diamond pattern, with either all wheels equal or rocking on the two fixed center casters. Trucks using this arrangement are very maneuverable and can be steered in straight lines, but require an even distribution of load for full stability and will not negotiate ramps.
4 Fixed
Four fixed casters mounted in a diamond pattern rocking on the two center casters. Maneuverability is limited and an even distribution of load is required for full stability. Not recommended for ramps.
3 Swivel
Three swivel casters of equal height mounted in a triangular pattern. Highly maneuverable, this arrangement gives stability on uneven floors although steering, particularly on uneven surfaces, is difficult.
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