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Chapter III:
Power wheelchair bases
When selecting your first power chair, chances are that you will be overwhelmed with the
selection and the features. You may feel like making a quick selection since you have so
many other medical issues to worry about. The decision, however, is very important since
this chair will be your child’s vehicle and mobility for many hours every day for several
years. There is NO perfect power wheelchair. Every type will have its tradeoffs – you
need to match the technology to your lifestyle and preferences as well as your child’s
medical needs. Here are certain features to consider and compare:
Drive configuration – location of the larger drive wheels on the base of the wheelchair
•
Front wheel drive
Large front drive wheels pull the weight instead of pushing
it. This allows for improved curb and obstacle climbing
capabilities, better handling in soft terrain such as grass and
gravel. It also provides very intuitive and tight maneuvering
(i.e. turning into a doorway from the hall). Since there are no
front casters spinning, you can pull in the footplates closer to the body, while still
maintaining a lower seat to floor height.
Disadvantage of the front wheel drive system is the potential for fishtailing – If
you go higher speeds the rear of the chair may “wiggle” around. This issue has
been resolved on some models but not all. The client also needs to get used to
having a lot of the wheelchair behind her, so she needs to be cautious when
turning in tight spaces.
•
Mid wheel drive
Mid wheel drive wheelchairs have the tightest turning radius.
While turning radius does not always equal maneuverability,
it is a very beneficial feature for indoor use. It is also intuitive
to drive since the drive wheels tend to be right underneath the
user.
Major disadvantage is a tendency to “highcenter” – this means that with 6 wheels
on the ground, the drive wheels can get stuck in the air when initiating a ramp or
other obstacle. More and more mid wheel drive configurations offer different
tracking and curb assist capabilities – while it is still not the best configuration for
outdoors use, the performance constantly improves.
•
Rear wheel drive
Rear wheel drive wheelchairs used to offer the best tracking –
that is, they were able to go straight without a tendency to veer
off to the side. With new gyroscopic and alike technologies,
both mid and front wheel drive configurations are getting
better tracking now. Due to the inherent tracking
