Everyday Front Casters
Wheelchair casters - come in a variety of diameters, widths, styles and sizes and each will have its own attributes that make it appropriate for different applications. The purpose of wheelchair casters is to stabilize the wheelchair while the drive wheels propel the wheelchair.
Caster load - (the weight on the casters) is a factor that affects the ability of the casters to roll over obstacles and the lower the caster load the smaller the casters can be and still function well. Caster loading is a factor that experienced wheelchair technicians take into account when setting up a wheelchair for a user, if possible, try to find an acceptable load level for function.
Caster diameter - The diameter of wheelchair casters can range from 3" for some rigid sports chairs to 12" for extreme rough terrain wheelchairs with the most common diameters on everyday wheelchairs being 4" (100mm) to 6" (150mm) with sports chairs being 3" (76mm) to 4" (100mm). Generally the larger the caster diameter the easier the wheelchair will be propelled over obstacles and rough ground. On the other hand, the smaller the caster diameter the easier the caster will swivel and the more responsive the wheelchair will be when turning. Based on this, one would think that the little 3" casters would be almost impossible to use outdoors however because the type of wheelchairs that use the tiny casters have their center of gravity centered on the rear wheels and there is very little weight on the casters.
Caster width - is another factor that affects how a caster will roll over rough terrain. The wider the caster tire, the easier rough terrain can be travelled over. Most manual wheelchair casters are around ¾" (19mm) wide with 2" (50mm) being considered wide. The heavier the combined weight of the wheelchair and the user, the wider the the casters have to be to prevent them from sinking into soft terrain and to enable the wheelchair to roll over obstacles.
Caster tyres - The tyres on the casters can be a huge factor on how easily the wheelchair will roll over all terrains. With the constant improvements with rubber compounds, the most popular choice for front castors on everyday wheelchairs are generally the hard and soft compound rubbers as supplied by company's like Frog Legs Inc with Court Sport chairs such as Rugby, Basketball and Tennis etc using the harder solid front castors for fast rolling and turning
Generally the harder the caster tyre or front caster, the easier the wheelchair will roll and turn corners. The softer the caster tire, the harder it will be to propel the wheelchair and the harder it will be to turn the wheelchair.
