Manual Wheelchair Caster Types and Sizes
Wheelchair casters are the small wheels on the front of a wheelchair that swivel when the wheelchair changes direction. On basic wheelchairs you probably won’t have much choice but on the lightweight and high performance chairs several options will be available.
Wheelchair casters are most commonly 8″ or 6″ in diameter, about 1″ wide and will be either solid rubber, have a solid insert or be air filled. Less common are 3″, 4″, 5″, 7″and larger than 8″ that can be found on wheelchairs designed for specific specialty uses.
Generally the larger the caster, the easier it is to propel the wheelchair over obstacles and rough terrain. Wheelchairs that are designed as all terrain or rough terrain chairs will normally have casters that are 8″ or larger in diameter. Sportier custom wheelchairs will usually have 6″ or smaller casters that are more responsive and make turns quicker but function less well on rough or soft surfaces.
Normally wheelchairs with casters 6″ or less in diameter will have adjustable axle plates that allow for adjustment to the chair’s center of gravity. By moving the center of gravity backward less weight is transmitted through the casters making the small casters function better when encountering soft or rough terrain.
Solid Versus Air, Versus Solid Inserts
Solid Casters are normally about 1″ wide (1/2″ to 3/4″ for 3″, 4″ or 5″ diameters) and are solid rubber, or similar material all the way through. Solid casters roll easily, don’t get flats and will last a very long time before wearing to the point that they need to be replaced. The biggest downside of solid casters is than every bump will be felt by the user but for most people this is not an issue.
Air filled casters
Air filled casters are normally a little wider than solid casters at about 1 3/8″ for 6″, 7″ and 8″ diameters and will have a treaded tire and inner tube much like a bicycle tire. Some chairs offer the option of 2″ or wider widths on air casters 8″ or larger. Air filled casters will give a bit of a softer ride than solid casters.
The biggest problem with air casters is they will wear out over time and tend to lose air pressure and can get flats. A soft, or worse flat, tire on a wheelchair caster makes the chair very difficult to propel and make turns.
The smaller the tire the harder it is to keep the casters inflated to an air pressure that works well which is why I don’t recommend air casters smaller than 8″ in diameter. Casters less than 6″ in diameter are not available with air tires.
Solid Inserts are air tires with a solid insert instead of an air tube inside. They will wear out over time and can be difficult to change but they won’t get flats and will maintain a firmness that will give a softer ride than a solid caster tire.