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Pneumatic versus flat-free power wheelchair drive tires was a simple debate in years past. If you wished a softer ride, pneumatic (air-filled), tires were the best choice, but at great risk of flats. However, if you wished to eliminate the risk of flat tires, your best choice was a flat-free (foam-filled), drive tire, but with a rougher ride quality.

Fortunately, modern power wheelchair technology has changed dramatically in recent years, making the choice between pneumatic and flat-free drive tires less of a give-and-take, and more of an easy decision.

Drive Tire Construction
Power wheelchair pneumatic drive tires are conventional by nature – featuring a soft rubber tire and an inner-tube, commonly inflated to 35 PSI on most rehab power wheelchairs – and it's imperative to maintain the tire pressure by properly inflating it approximately every two weeks. Of course, pneumatic drive tires are at risk of puncture-related flats – actually quite easily because power wheelchair tires are relatively thin – and to repair a flat tire, the power wheelchair must be elevated off of the ground, the drive wheel removed, the rim unbolted in halves, the tube replaced or patched, then reassembled (needless to say, not an achievable task for those with severe disabilities).

Flat-free drive tires are an outer “pneumatic,” soft rubber tire, as well, but instead of an air-filled inner-tube, the void is filled with a modern, specific-density foam, one that matches the tire's maximum PSI, where the ride quality equals a fully-inflated tire. (More recently, an even newer flat-free tire construction has entered the global market, where a layer of gel is placed atop the foam for a softer ride; however, thus far, the technology proves problematic in that the tires equate to a “half-inflated” tire, dramatically increasing rolling resistance and tire wear). Predictably, the absolute benefit to flat-free drive wheel tires is that they'll never leave you stranded, and are maintenance free – that is, they typically don't need to be touched until the tread wears out. (If you let foam-filled tires sit on an unused wheelchair for months in one spot, they can develop a “flat spot” where the power wheelchair compressed the foam insert, but this isn't an issue for regular users.) Lastly, foam-filled tires shouldn't be confused with polyurethane “solid” tires, which aren't used on higher-end power wheelchair drive wheels due to limitations in durability and performance.

In all, if you look at a pneumatic and a foam-filled power wheelchair drive tires side-by-side, you can't tell the difference – it's what's on the inside that sets them apart.

Ride Quality
A foremost difference between pneumatic and flat-free drive tires that users have long noted is that pneumatic tires offer a softer ride than flat-free tires. And, it's true – but only when pneumatic tires are under inflated. Again, on an industry-standard 14”x3” drive tire, for example, the modern foam density equates to the tire's maximum PSI rating, so when you compare, say, a 35 PSI foam-filled tire to a properly inflated 35 PSI pneumatic tire, the ride quality and performance characteristics are truly the same.

Now, a seeming advantage to pneumatic tires remains that the air pressure can be decreased for a softer ride – but not without consequences. Reducing the air pressure in a tire increases rolling resistance, which decreases battery range and dramatically increases tire wear. For these reasons, maintaining maximum tire PSI is recommended – and if you need a softer ride, strive to address it at the power wheelchair's suspension, not the tires.

Additionally, some users believe that decreasing the tire pressure will increase traction, but there's simply not enough surface or volume on a typical 14”x3” power wheelchair tire to dramatically alter the power wheelchair's performance by decreasing the air pressure. In fact, lowering the tires' air pressure on 6-wheel power wheelchairs can actually decrease traction, as it redistributes weight away from the center drive wheels, placing it on the front and rear casters, reducing drive wheel traction. Therefore, when you hear people recommending lowering the air pressure on typical power wheelchair tires to improve traction, they're truly misapplying techniques used on vastly different vehicles, and don't understand the mechanical aspects of modern power wheelchairs, especially those in the 6-wheel suspension arm class.

Efficiency
Unquestionably, pneumatic drive wheel tires are more efficient than foam-filled, flat-free drive wheel tires. The fact is, foam-filled drive wheel tires are heavier than pneumatic drive wheel tires, and a heavier wheel requires more energy to accelerate. Therefore, each time a power wheelchair accelerates, it uses more energy doing so with a foam-filled drive wheel tire than with a pneumatic tire. If you wish the absolutely most efficient drive wheel tire, then, pneumatic is the best choice.

Still, drive wheel tire efficiency isn't only about the type of tire, but it's also about how it's maintained. Again, pneumatic tires require routine inflation, and if not properly maintained, a pneumatic tire that's low on air will dramatically decrease a power wheelchair's efficiency. In this way, foam-filled tires can prove more efficient in the long term for those who don't routinely air up their tires, as foam-filled tires consistently perform at a full PSI.

A Special Consideration for 6-wheel Power Wheelchairs
Flat drive wheel tires on 6-wheel power wheelchairs can be especially debilitating, rendering a power wheelchair all but inoperable. A flat tire on a rear- or front-wheel drive power wheelchair will cause it to lean, but still drive at a reduced pace. However, when the drive wheel goes flat on a 6-wheel power wheelchair, it redistributes the weight to the front and rear casters, effectively high-centering the drive wheel, eliminating most traction. As a result, driving on flat ground is very difficult, and ascending transitions like ramps is often impossible.

Can You Truly Afford A Flat?
Ultimately the choice for many in deciding between pneumatic and foam-filled drive wheel tires isn't about technology, but about abilities and lifestyle: Can you, personally, afford to get a flat tire on your power wheelchair without it drastically affecting your life?

There are some individuals who remain semi-ambulatory, with full upper body use – and are tinkerers by nature – who are able and glad to roll their power wheelchairs into their garages and change a tire. For them, a flat tire isn't debilitating, just a temporary task.

However, for others with severe disabilities, where if their power wheelchair gets a flat tire, they have to rely on a provider, there can be great consequences. For them, a flat tire can mean being without mobility for several days – a life-altering consequence.

In these ways, it's important to understand one's abilities and the potential consequences of a flat tire, deciding whether pneumatics drive wheel tires are worth the risk, or if foam-filled, flat-free tires are the securest solution?

Making the Call
While there are die-hard holdouts who still swear by pneumatic drive wheel tires, it's increasingly difficult to dispute the overall merits of foam-filled, flat-free drive wheel tires on modern power wheelchair technology. Under ideal circumstances and maintenance, surely pneumatic drive wheel tires offer great efficiency and performance; however, many users don't live in ideal circumstances, and can't risk flats. Furthermore, with specific-density foam-filled tires, and most power wheelchairs now featuring suspension, the days of rough riding flat-free tires are over. With all said, it's hard not to make the call that for users wishing utmost long-term performance and reliability, foam-filled, flat-free tires become the easy choice on modern power wheelchairs.

Published 1/2010, Copyright 2010, WheelchairJunkie.com