Why Caster Position Matters
As stated in the articles regarding centre of gravity, it is usually best to locate the casters as far forward as possible. But since wheelchair prescription is a series of compromises, one needs to understand what suffers when something is improved.
Consider the TiLite ZR, ZRA, TX and TR since these chairs are essentially custom made and offer configurations that are virtually unlimited. When looking at the side elevation (side view), the greater the distance between the rear wheels and the casters, the less weight there will be on the casters. This is a good thing ... but like chocolate, too much is not a good thing. Looking at a front view, it is desirable to minimize the distance between the casters. The issues that impact on how far they can be pushed forward and brought inward include:
- Mitigated by...
- More taper
- Less tight front end (e.g. 80° rather than 85°)
- 90° footrest loop (squared off rather than radiused) to allow more caster wheel intrusion into the medial space.
- Smaller diameter casters
- Pushing the casters forward may require that they be moved laterally to clear the footrest assembly. For lateral transfers, it is more difficult to gain a close approach to tub, toilet, bed, car, etc. if the caster assembly is protruding.
- With a wider front end, it is more difficult to negotiate confined spaces
- Casters too far forward will inhibit the approach to objects
- Casters too far forward may interfere with transfers
- Casters too far forward may make the “package” too big to transfer into a vehicle