This 'high-end' wheelchair, utilizing a titanium main 'box' frame and mostly aluminum parts, weighs 30.68 pounds.
In order to determine what parts need to be replaced versus capable of being re-used and/or adjusted,
it's important to be able to inspect everything at the 'bare metal' level.
In spite of this being a 'high end' wheelchair, there is a significant amount of rust and seizing of the steel
parts, as well as corrosion of the aluminum casting parts used.
There are two main drive wheels, one on each side of the wheelchair. They are powered by the chair's user who uses their hands placed on the 'handrims,' allowing a smoother surface than gripping the tires. The handrims on this model are hollow aluminum tubes bolted to the main wheels' rims. The original rubber outside grip-strip was deemed to be a 'negative feature' and removed by the user.
Wheelchairs tend to use 24" tires, also used in the bicycle industry (although not as common as the 26" size).
Each of the two drive wheels has two bearing each,an inner one and an outer one.
This shows the outer wheel bearing on one of the drive wheels.
It is a R8-2RS ball bearing, with rubber side ("RS") seals.
These bearings were still in good condition, likely due to the fact that they are protected from the elements
inside the wheel's hub, hidden by the axle's quick-release button.
Specs for a R8-2RS bearing (per grok-3):
The R8-2RS bearing is a miniature deep groove ball bearing with the following specifications:
You can buy these R8-2RS bearings for $9/each from wheelchair dealers, OR get 10 of them for $8 from amazon (e.g., https://www.amazon.com/Sackorange-R8-2RS-Premium-Sealed-Bearing/dp/B07DCQLCS3). They are bog-standard bearings and mostly come from the same factories, often in China and Korea. There is nothing about these "wheelchair" bearings that justifies the greater than 1,000 percent markup. Still think that DOGE is without merit? A total of 8 of these bearings are needed per wheelchair. For bicycle wheel hubs, the 6802-RS and 6902-RS bearings are very common, and sometimes the only difference is whether it is an Imperial (American/SAE) or metric size. The R8 is an Imperial size.
This shows the inner wheel bearing on one of the drive wheels. It is also an R8 bearing, the same size
as the outer bearing, but with a steel side protective cover.
These bearings were seized up, likely due to the fact that they are facing the seat and subject to dirt exposure.
It will be interesting to see if the manufacturer fixed this in later models.
The wheels still turned, but there was increased friction because the inner bearing surface rubbed against
the axle shaft.
Bearings on wheel chairs don't "wear out" since these bearings are made to last for thousands of miles
in transport terms, while most wheelchairs probably only travel hundreds of miles during their lifetime.
They "fail" because they get contaminated by the elements in the envirnonment in which they are used.
This bearing, the top one in one of the swivel wheel fork supports, accumulated enough water over a number
of years to wash out the lubricant and cause surface rust inside the bearing. Removing the protective seal,
which in this case didn't do its job very well, shows the resulting mess. If caught early enough, the bearing
can be cleaned out and relubricated manually, adding years of future use to its life.
There are two of these for this wheelchair, one on each main wheel. They are not really 'brakes' in the sense
that they are used to slow the wheelchair, but to lock the wheels so that the wheelchair doesn't move.
They are functionally used as 'parking brakes.'
This photo shows the left wheel brake prior to removal.
This is the side of the brake assembly that faces the inside of the wheelchair.
This is the view of the parking brake from the outside.
These brakes have no 'broken' parts, but the attaching hardware is rusted, and the 'pivot rivet' articulating joint pins need to have their nylon bushings replaced. These rivets would have to be drilled out to be removed, requiring replacement rivets (hinge pins) as well. The main issue here is that these parts are not likely to be separately available.
We ended up replacing the brakes/wheel locks with a set from amazon ($46) for a 1" tube (as measured with a digital caliper).
Each of the two caster (forward) wheels has two bearings each. Each of the caster wheel swivel forks
also uses two bearings. If any of these eight caster bearings have excess play it will result in a wobble in
the caster wheel at higher speeds.
This shows one of the two bearings used in each caster fork (front wheel swivel) assembly.
Per the model number, they are the same bearings used for the main drive wheels.
By: TiLite - Permobil
Part Number: HD100011
Description: BEARING 1/2"ID X 1-1/8"OD X 5/16"
You can buy these R8-2RS bearings for $9/each from wheelchair dealers, OR get 10 of them for $8 from amazon (e.g., https://www.amazon.com/Sackorange-R8-2RS-Premium-Sealed-Bearing/dp/B07DCQLCS3). They are bog-standard bearings and mostly come from the same factories, often in China and Korea. There is nothing about these "wheelchair" bearings that justifies the greater than 1,000 percent markup. Still think that DOGE is without merit? A total of 8 of these bearings are needed per wheelchair.
There are two of these for this wheelchair, and both are mounted forward of the main wheels and keep the chair
from tipping forward. The wheels are mounted in forks which allow continuous swiveling around a 360 degree
circle. These nominal "8 inch" pneumatic wheels are designed to be inflated via a Schrader automotive type valve.
The bearings used on the caster wheels are significantly smaller than the other bearings used on this chair. The identifying markings on these are no longer legible, but the axle size is 5/16" (???) and the bearing's outer dimension is 1" (???).
Q for grok-3 (XAi.com): For the wheelchairs made by TiLite in 2008, was the hardware (nuts and bolts) used metric or American (SAE)?
Grok's reply: In 2008, TiLite wheelchairs primarily used SAE (imperial) hardware for their nuts, bolts, and other components. TiLite transitioned to metric hardware in 2018, as noted in multiple sources, meaning all their wheelchairs produced before this change, including those from 2008, were built with imperial-sized hardware. For example, a Reddit discussion about a pre-Permobil TiLite ZRA mentions screws in inches (e.g., 1/4"x28 fine thread), reinforcing that older models used SAE standards.
If you need specific part details or replacements for a 2008 TiLite model, you may need to consult the owner's manual or contact a supplier like DME Hub, as imperial parts for pre-2017 models are no longer supported by TiLite and may be considered "out-of-stock."
The use of unprotected steel nuts and bolts makes standard removal techniques impractical for some assemblies.
Here a nut needs to be removed with a disc grinder to allow removal of the seat mounting adjustment arm.
The arm is made of plastic, so heating with a torch is not an option.
The photo below shows a crack in the titanium main 'box frame' tubing. This was hidden by the wheel assembly mounting bracket, which also had the effect of keeping the crack from breaking further. The clamping force of the mounting bracket may or may not prevent the frame from failing in the future.
TiLite's advertising claims for this model include this:
"The Tru-Fit System opens up the world of adjustability by incorporating an infinite adjustment mechanism. The Tru-Fit system allows you to fine-tune the fit of your chair because you are not limited to a series of pre-set holes. Also, instead of bolting through frame-weakening holes, components clamp directly onto the frame. This eliminates one of the main stress points on today's wheelchairs by reducing the number of holes in the frame."
Unfortunately the photo of this crack shows that TiLite's strategy didn't go far enough.
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https://www.southwestmedical.com/replacement-parts/tilite/tilite-2gx/crosstubes/15-wide/1-crosstubes (see ), Display a PDF file ... (PDF, # pps, 20??)
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