How Power Wheelchair Measurements & Drive Wheel Choice Are Related

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Make a drive-wheel choice — front, mid or rear — for a power wheelchair, and you’re simultaneously making a choice regarding power base measurements. For example, rear-wheel-drive power chairs have traditionally had longer wheelbases, which translates into needing more room to turn. A larger turning radius can mean tougher maneuvering in smaller or narrower spaces, such as elevators, hallways and homes.

Of course, a power base is far more than its turning radius, and a turning radius is only one part of the decision-making process.

“The selection of drive-wheel placement on complex rehab power chairs,” said Ayron King, ATP, Power Sales Specialist, Sunrise Medical, “is a decision that entails many factors that need to be considered during the evaluation and home assessment stages of the funding cycle. The common known facts to evaluate include access in the home, community, van or transportation, along with school and/or workplace environment. Whether it’s front-, mid-, hybrid-, or rear-wheel drive, there are many benefits and differences for each selection.”

Front-wheel drive, King said, “allows for the drive wheel to be the first point of contact with obstacles, rather than a caster wheel that relies on the drive wheels to track straight over thresholds. Front-wheel drive should also be the first consideration when it comes to bariatric power wheelchair end users due to center of gravity. The home environment should be an open-concept floor plan, along with access to bedrooms, bathrooms and other rooms that they are required to access.”

Today’s popularity of mid-wheel-drive power chairs can be equated, King said, to “indoor accessibility, turning radius capabilities, cognition in relation to space, and the requirement of all-day access for tight spaces in and out of the home. Today’s recent suspension upgrades have made mid-wheel-drive chairs capable of handling outdoor terrain much better than in the past. Before recent upgrades to mid-wheel-drive designs, road vibration was significantly more harsh to this platform than to frontwheel drive designs due to drive wheel impact placement.”

Hybrid/rear-wheel-drive power chairs — the “hybrid” tag in recognition of the fact that today’s drive wheel is typically not as rearward as it has been in the past — is admittedly not the most popular choice, but its fans tend to be loyal. The configuration has “a special place in the complex rehab technology industry,” King noted. “Rear-wheel-drive power wheelchairs typically meet the needs for end users who require and enjoy full power coming from the back portion of the frame. Active outdoor users typically need the climbing and suspension capabilities these chairs can provide. A rear-wheel-drive power chair requires a larger turning radius, awareness of surroundings, and open floor plans for everyday use.”

King said consumers absolutely get used to and get attached to their power chair’s drive configuration — and making a change after a number of years in one configuration can be tricky.

“My rule of thumb is to stick with what they’ve had,” he said. “I’ve talked a few people into [changing configurations]. We haven’t had great outcomes, and then they’re stuck for five years. So if you’re going to change them, the most important thing is doing appropriate trials in all their environments and making sure they can access everywhere they go.

“If they can’t access one thing that they’re accustomed to doing every day, it’s going to [result in] a chair return. It’s not going to be a good outcome for them, and that’s why the trials are so important.”

This article originally appeared in the October 2018 issue of Mobility Management.

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