A problem with mid-wheel drive that never seems to be mentioned by the manufacturers but
does come up in discussions by mid-wheel drive owners is called Caster Jerk. This is not the
typical flutter of any caster. It is a jerk or lurch to the side. The leg rests and foot plates
bash walls, scratch furniture, and inflict great pain on any ankles that get in the way!
Any wheel chair has some caster jerking as the casters swivel 180 degrees from forward to
backward. There is resistance to the swivel until it reaches 90 degrees and then it finishes
the swivel quickly causing a little jerk in direction. The movement is slight and soon
With a mid-wheel drive however, there are four casters attempting to change direction 180
degrees. The jerk is accentuated and can be a problematic lurch to the side. This is minor and
easily accommodated to in average size rooms where the casters have enough distance to travel
to move more smoothly through the swivel. This can be adjusted with steering control settings
or may require moving the entire seat on the base. It cannot be eliminated entirely.
In small spaces it becomes a significant problem if it is necessary to back up, turn, and pull
forward again to position the chair correctly. When there isn't enough space/distance for
the casters to swivel smoothly, they jerk the chair quite powerfully to one side. The jerk
occurs even after the joystick is released and even if you attempt to steer to the opposite
side. Perhaps the most frustrating aspect of caster jerk is that once you are in a tight space
you can't adjust the position of the chair without repeated jerks. Times when you are
likely to encounter jerking include maneuvering in a small bathroom to position the chair
accurately beside the toilet or at the sink, at a computer desk where you need to be centered
and straight on, in a van where you need to face forward in alignment with the tie downs, in
doctors and dentists exam rooms, restaurants and buildings with small entries.
The jerking problem is one that most users become accustomed to and they love their mid-wheel
chairs, but will admit jerking does occur and is annoying. People for whom the mid-wheel drive
is their first chair accept the problem as part of wheel chair life. Switching from rear wheel
to mid-wheel is more difficult. The jerking is more obvious, and can make rooms and spaces
designed for a rear wheel drive very difficult in a mid-wheel drive.
For people who can drive themselves, a mid-wheel works well, but when they deteriorate and an
attendant must drive, it can be problematic. Each caregiver must work with the chair often
enough to overcome the learning curve for basic driving and, depending on the home layout, for