… try having a flat tire on your wheelchair.
The post in brief
That’s the first lesson I learned, helping a friend do some maintenance on her wheelchairs over the past couple of weeks. Mostly replacing tires and various wheel bearings. Breakdowns are unacceptable.
The second lesson I learned is that if a replacement part says “wheelchair” on it, it’s going to about ten times as expensive as you would guess. Even if it’s just a generic, high-volume, mass-produced part that happens to fit a wheelchair.
Hence, simple low-speed bearings advertised to fit a specific brand of wheelchair are normally $9 each via DME supply websites. But the identical sealed bearings are $0.80 each via Amazon.
How can that be? Breakdowns are unacceptable. Absent the right tool to measure it accurately, the only way the typical wheelchair user can be assured that a bearing will fit is to order the bearings that are “for” that particular chair. And, because (see red phrase above), wheelchair users will quite reasonably pay the premium for the assurance that they are getting the right part.
I hate to use this word, but my impression is that the Durable Medical Equipment (DME) industry exploits wheelchair users. Or, more rationally, the industry prices repair products knowing that for the typical user, (see red phrase above). As a retired health economist, I realize that anything having to do with mainstream health care is going to be expensive. As such, I assumed that I was used to product pricing that took your breath away. But even to my jaded eye, pricing of wheelchair repair parts seems to be a step beyond.
The third lesson I learned pertains to solid-rubber tires and solid-rubber tire inserts. From the perspective a of a life-long bicyclist, these products have so many practical drawbacks that you might reasonably ask why would anyone use them? Breakdowns are unacceptable. Those are the only sure-fire guaranteed ways to avoid flat tires, because they aren’t filled with air. So they are useful on wheelchairs, despite being tough to work with.
How tough to work with? For the amateur, using normal hand tools, I’d rate it as screaming curse-filled tough. Ultimately, touch-and-go as to whether or not I can actually get the tire on the rim tough.
How can that be? For solid-rubber tires, imagine that somebody gave you a rubber band, and asked you to stretch it over a bike tire rim. What’s the catch? The rubber band is about an inch-and-a-half thick, and considerably smaller than the rim it must be stretched over. I’m guessing it takes about a thousand pounds of force to stretch it enough. The force required exceeds what some garden-variety hand tools can take. And is right at the limit of what a normal human being can produce without specialized tools.
By contrast, with solid-rubber tire inserts, (basically, a solid foam replacement for the inner tube), the whole process amounts to abuse of a bike tire. In effect, instead of mounting a bike tire, then inflating it, you do it backwards. You have to mount the bike tire while it’s fully inflated. Which is something that a bike tire — with steel wire embedded in the tire bead on both edges — is specifically designed NOT to do.
Solid tires and solid tire inserts provide yet another example of an internet that only shows you the happy successes, not the failures. If you want to hear about the failures, read the comments on Amazon (below). As a life-long bicyclist, I’d never seen bike tires where easily one-in-five purchasers was literally unable to get the tire mounted onto the bike rim.
I, by contrast, walk through my curse-filled success, in excruciating detail, below.
My only practical advice from all of this is the following:
To a close approximation, bearings are bearings. At least for the low-speed application of wheelchair casters and rear wheels. On Amazon, you can be assured that if bearings routinely fail in normal use, you’ll read about it in the comments. But they won’t. Bearings are the sort of product that in order to make them work at all, you have to make them pretty well in the first place.
If I had to do the tires over again, I would go with solid-rubber tires (not inserts), and I would without a doubt buy the specialized, $35, solid-steel, bolt-to-the-workbench tool specifically designed for mounting solid-rubber tires on wheelchair rims. (Like this one). Trying to mount solid-rubber tires with ordinary hand tools has high risk of injury, damage, and outright failure
Tedious detail follows.
Background: Minimizing the risk of a flat tire on a wheelchair
I have no bona fides for working on wheelchairs. My only training for this is that I’ve been repairing my own bicycle wheels for my entire adult life.
Anything specific to wheelchairs I have learned on the fly, helping a friend replace tires and wheel bearings on one of her wheelchairs.
For the bearings, there are numerous YouTube videos showing various methods to replace them. And as far as I can tell, it’s just about as easy as those videos suggest. Pound them out (with flat-bladed screwdriver and hammer), and pound them back in (with a block of wood, and a hammer). Plus or minus some blue Loctite to help hold them in place.
The tires, though, were a different thing entirely. My friend wanted solid tires of some sort (either literal solid rubber tires, or tires with solid foam inserts, instead the air-filled inner tubes that are typical for bike tires). Those foam-filled tires turn out to be really hard to install (see below). Plus, they’re less comfortable than standard pneumatic tires, transmitting more of the shocks of uneven pavement to the wheelchair user.
So I asked, why solid tires? Why not regular bike tires with inner tubes?
I got the response shown at the start of this post.
And that stopped me in my tracks. On a bicycle, if you get a flat, you just pull the wheel off the bike and change the tube. Simple enough, if you’ve done it a few times. And so I was thinking about this like a bicyclist.
But if the flat tire is on a wheel that is currently holding up your wheelchair? That’s a whole different ballgame. Not that a wheelchair user couldn’t transfer to another seat, assuming one was available. Then proceed like the bicyclist, and transfer back. But that’s clearly a different order of magnitude for hassle and effort. Particularly, say, if you’re at work, running errands, and so on.
In a separate post, I’m going to discuss what I’d do, as a bicyclist, to minimize the hassles of flats using standard air-filled (pneumatic) tires.
For now, I’m just going to give you an accurate description of my experience mounting one solid-rubber tire, and two tires with solid-rubber inserts, on some 24″ wheelchair wheels.
Airless tires: How to change a bike tire with a hammer.
Above: Tools not normally associated with changing a bike tire.
There are two types of non-pneumatic (airless) bike tires. There are solid tires, which replace the traditional bike tire, and there are solid foam inserts, which are used in place of an inner tube inside a regular bike tire.
As a service to those who may be thinking about putting solid tires on a wheelchair or bicycle, let me describe how that went, for me. Because mostly what you see on the internet is people who can demonstrate how easily something can be done.
Mainly, it’s hard. Really hard. So be prepared. I’m a pretty big guy. I’m no Schwarzenegger but I lift weights regularly. Solid and foam-insert tires took me right to the limit of what I can do with hand tools.
Of the two, if you are using ordinary hand tools, the foam inserts were somewhat easier to do. Note that I did not say easy, just easier than the solid foam tires. That’s assuming you got the exact right foam insert (it must match the tire size), that your tire is an ordinary tire (and not some super-tough premium tire).
But if I had it to do over again, I’d go with solid tires, after I’ve bought and installed the special jig needed to mount those on rims.
Solid tires: Buy the tool first.
Source: Amazon.
Solid tires are exactly what they say they are: They are a solid ring of synthetic rubber. Basically, they are a bike-tire-sized inch-thick O-ring, with tread, meant to replace a traditional pneumatic bike tire. They look like a regular bike tire. But they are solid rubber.
They have to fit the rim really tightly in order to stay on in use. To ensure that, manufacturers make them an inch or two smaller than the circumference of the rim. Which means that you have to stretch a thick piece of tough rubber, that much, on the fly, in order to get the tire up and over the rim of the wheel.
I did one by hand, without the correct bench-mounted tool (below). I managed to do it, but I broke several tools in the process, and felt lucky that I didn’t break any bones. Heating it up helps, but only a tiny bit. In the end, I did it by working my way around the rim using the biggest screwdrivers I own, with a piece of pipe as an extension, to lever the tire up and over the rim. That, plus clamps to hold the tire in place once it was over the rim. And a heat gun, to keep the rubber warm and pliable. And a lot of muscle power. And copious swearing.
Even with that, I damn near gave up. And I’m far from alone. For example, for this solid tire on Amazon, roughly every 5th review was from somebody who tried and failed to get the tire on the rim. Like so:
Source: Amazon.
There is a solid-steel bench-mounted tool designed for installing solid tires. You can see a pro, using such a tool, in this YouTube video. He makes it look easy, but note how hard he has to haul on the bike rim to get the tire mounted.
Maybe there are solid tires that are easier to install. Maybe if your rim is just the right size or shape, it’s not so hard. As for me, I’m never trying that again without the proper solid-steel installation tool shown in the video above. Once was more than enough.
Solid Foam Tire Inserts: Tire abuse.
Source: Amazon.
Foam inserts take the place of normal pneumatic inner tube. Like the foam tire, a foam tire insert is basically a gigantic synthetic rubber O-ring. You place this in a regular bike tire, and then (attempt) to mount the bike tire as you would normally.
The task gets harder as you progress.
First you slip one bead of the tire over the rim, as you would for mounting a bike tire normally. This is no different from mounting a regular bike tire. All you need is a couple of small bike tire irons or tire “spoons”.
Second, you slip this new foam core over the rim. This requires at least some long screwdrivers, for leverage. And some significant muscle power. But it’s not all that hard if you have the arm strength and the leverage.
Finally, you have to slip the second bead of the tire over the rim, and get it to seat on the inside of the rim.
This is the part that I refer to as “tire abuse”, because you are, in effect, trying to mount a tire after it’s been fully inflated. Tires do NOT want to do that. The wires embedded in the bead of the tire are, in fact, specifically designed to prevent the tire bead from moving over the edge of the rim, once the tire is inflated. That is their entire purpose in life. And unlike the rubber, those wires in the bead do not stretch. The upshot is that you have to fight the fundamental nature of the bike tire in order to mount it.
That’s where the clamps, multiple tire irons, pipe extensions for leverage, water-pump pliers, and hammer come into play. The water-pump pliers and hammer are for seating the bead of the tire, once you’ve managed to slip it over the rim.
With sufficient leverage, working a few inches at a time with a handful of steel tire irons or flat screwdrivers, it’s not too difficult to get the bead of the tire to go over the edge of the rim. But then it just sits there, instead of seating well down inside the rim, because the foam insert is in the way. So my solution was to grab the tire with water-pump pliers and twist it, to coax the bead to go inside the edge of the rim.
Kudos to Mr. Ron Friedrich (via this YouTube video) for the tip about the water pump pliers. I wouldn’t have had the courage to abuse a bike tire that way without seeing somebody do that first. And ultimately, that was my inspiration for using a hammer. I figured if water pump pliers were fair game, nothing should be considered out-of-bounds.
Then beat the tire with a hammer, right at the spot where the bead needs to be driven down into the rim. This both relieves stress (of the installer, not the tire) and eventually works the bead down below the edge of the rim, where it belongs.
Lever up another few inches of tire, and repeat.
This was hard, but not as hard as putting on a solid tire without the proper tire installation tool. As evidenced by the Amazon comments, such as those below. I didn’t see anyone who gave up, but many people made comments about the difficulty of installation.
One more point: Once a tire has been properly installed with a foam insert, the only way to remove the tire from the wheel is to cut the tire off. Take a utility knife (Skil knife), cut through the tread all the way around the circumference, then pull the tire halves out using pliers or vice grips. The foam insert is then re-usable.
One more, more point: The foam insert must match the tire exactly. On my first attempt, I destroyed a tire because it was a high quality tire with a very thick, puncture-resistant section under the tread. That made the foam insert too large for the tire, and I ended up having to cut the tire off to remove it. (By the time I realized it wasn’t going to go on, it wouldn’t come off, either.) Only when I tried again with cheaper, thinner tires that were matched to the insert did I manage to get the tire on correctly. So my advice is, if you go with foam inserts, go with cheaper, thinner tires.
Conclusion: Solid rubber tires and tire inserts
I definitely see the advantage now, for use on wheelchair rims.
But these are not for the faint of heart. That’s how I characterize solid rubber tires and tire inserts.
You can find all kinds of pleasant success stories laid out in YouTube videos. What you don’t see is the folks who tried to mount these products on their rims, and either failed, or both failed and destroyed their rims in the process.
I’m very mechanically inclined, I know all about using “cheater bars” to extend the leverage of wrenches and such. And I was within a hair’s breadth of giving up on both the solid tire mounting, and the solid insert mounting. For my part, I’d never try solid tires again without using the tool specifically designed for that task.
I’m not saying don’t do it. I’m saying that if you’re going to try this yourself, using common hand tools, you need to go into it with your eyes open.
