FAQ / Technical Guidebook
FAQs and useful information on using office chair casters.
There is a simple rule for this:
- hard floor = soft casters
- soft floor = hard casters
This is a safety feature. Office chair casters are equipped with a load-dependent brake. This means they lock if there is no load that stops the office chair from rolling away uncontrolled when standing up. When loading again, thus when you sit back down, the brake releases and the casters can run free.
When using your casters, have you taken the rule from point 1) into consideration? Hard floor = soft casters, soft floor = hard casters.
The marks on your floor probably depend on the quality of the tread material of the casters. Gross Stabil twin wheel casters are coated with high-quality plastic. This is decisive for the abrasion condition of the casters, marks on the floor will therefore be avoided.
There are different reasons for this:
- wear due to age
- the use of aggressive cleaning agents
- excessive UV radiation
In all cases, we recommend that you replace these casters with new ones.
We generally advise against only replacing individual casters. The complete set of casters must always be replaced, generally 5 items.
Technical Information on Casters
Twin-wheel casters, wheel diameter 32 - 37 - 40 mm = furniture casters
Twin-wheel casters, wheel diameter 50 - 55 - 60 - 65 mm = office chair and furniture casters
Twin-wheel casters, wheel diameter 75 - 80 - 100 mm = furniture casters
We also supply single-wheel and roller casters, caster modules and caster cups as well as chair and furniture glides.
There are hard and soft wheels. Soft wheels have a contact surface of non-smearing, abrasion-resistant polyurethane.
The following general rule applies:
- hard wheels for soft surfaces such as carpets and linoleum
- soft wheels for hard surfaces such as tiled, parquet or laminate floors
- spindle with retaining ring
- screw-on fixture plate
- threaded spindle
Please refer to our catalogue for the various types. Special spindles can be supplied to the customer's specifications.
- un-braked: free-running, without brake or locking mechanism.
- load-dependent braking: the brake is only applied to the caster when not under load. That means it will not shift when you stand up.
- braking under load: the caster brakes the chair or furniture only when under load. That means it will not roll while sitting down.
- wheel-locking: the brake lever locks the wheels.
- complete braking: the brake lever locks the wheels as well as the swivel movement.
The load capacity in kg is approximately the same as the wheel diameter in mm. Please refer to our catalogue for further details.
We recommend the following approximate calculation for furniture on 4 casters:
required load capacity per caster = (weight of furniture + guaranteed maximum loading) x 1/3
Our casters are available for a variety of recess diameters. This enables optimum matching to the office chair base. Casters are also available with universal adaptors for special applications.
Before an object on casters can start to move, three resistances have to be overcome by force. The resistances are depend on the following factors: weight, wheel diameter, load on the casters, material and shape of the contact surface and the type of the floor.
The x-value shown in our catalogue for each type of product has to be added to the y-value of the fixing used. The y-values can be found in the catalogue in tables at the end of the catalogue.
Besides plastics (PA6, TPU, etc.), we use zinc die-casting for certain designs, which can be chromium-plated or powder-coated in a variety of colours.
Casters which conduct electricity are capable of earthing electrostatic charges. Their electric resistance is R = 104 Ohm.
The following standards apply:
- EN 12528 for furniture casters
- EN 12529 for braked and unbraked chair casters
Both European standards define the technical requirements, suitable dimensions and requirements for testing.
We can also produce casters to custom-designed specifications.
In order to ensure a caster's long service life, the following recommendations should be followed:
- The load must not exceed its load-bearing capacity
- It must not be used on unsuitable surfaces
- The ambient temperature must not be too high or too low
- Furniture with locked brakes should not be moved by force
- It must not be subjected to particularly aggressive agents (cleansing, etc)
- It must not be subjected to improper shock-loading or being dropped
- The casters should not be moved at speeds above 4 km/h (2.5 mph)
- No modifications should be made without consultation.