Overview

My husband has seizures when he is bumped around too much. We are looking for a solution for outdoor rear wheels and or tires to help with shock absorption. We don’t have a budget for anything too big right now, so I would like to see what can be done with what we have for his TiLite ZRA wheelchair.

The primary use will be for outdoors on bumpy streets and when using his Rio Mobility Firefly handbike. We live in Europe with many bumpy brick roads, but they will not be taken off-road much and he will not be self-propelling much with them on or use them when indoors. It’s the constant small bumps of brick roads and having to struggle to hold himself steady over them that cause the seizures (the concentration needed is a trigger).

These are pictures of the  roads in front of our house that are typical of the type we want to have some shock absorption for:

What we have now for wheels / tires

We have the most common size wheelchair wheels now which are 25-540 (24 x 1″). Unfortunately, it is very difficult to find tires that fit this size rim for outdoor use that have shock absorption for a smoother ride. Most outdoor tires are made for 507’s (24″ MTB/BMX) or 559’s (25″ wheelchair / 26″ bicycle).

We have 2 sets of 24″ Spinergy LX’s (540’s) wheels. One set is used on the TiLite ZRA with Marathon Plus Evolutions 25-540 (24 x 1.0″). They work great indoors for everyday use and outdoors on smooth pavements, and we would like to keep that setup. The other set is on a TiLite 2GX chair that we use upstairs, with standard 32-540 (24 x 1.375) with airless inserts. The airless inserts are a hard bumpy ride, along with being very heavy, so we don’t want to use them outdoors. Both sets of wheels have D’s Locks hub locks on them.

We also have another set of TiLite Shadow (540’s) wheels with Primo V-Traks 25-540 (24 x 1.0″) that we got when ordering the TiLite ZRA. They would be the easiest to swap out the tires on, but then I am concerned that we would loose the shock absorption quality of the Spinergy PBO spokes and will not be as strong as the Spinergy LX’s when using the Firefly. Also, they do not have D’s Locks hub locks on them, so we would need to purchase the lockring adaptors or mount push-to-lock wheel locks on the wheelchair.

Option 1) Shock Absorbing Wheels

We have also considered that maybe it would make more sense to start saving up for suspension wheels. There are 2 types that we have found available, but both are very new.

Loopwheels

Loopwheels are designed to help you push over uneven streets, cobbles, grass, rough tracks and gravel paths, with less effort.    The composite springs give you extra power to get up or down kerbs. Loopwheels are more comfortable than standard wheels: they absorb tiring vibration, as well as bumps and shocks. They’re also extremely durable. With quick release axles and two sizes (24″ and 25″), loopwheels fit most active wheelchairs.

Loopwheels are designed, engineered and made in Nottinghamshire UK by Jelly Products Ltd. They started as a Kickstart project and are available for wheelchairs as well as bicycles.

they can be ordered on their website and start at about GB £695 (ex. VAT) for black, which is about Euro €877 / US $999, and run higher for different colours and options for hand rims. They appear to ship internationally.

Specifications

• 24 inch loopwheel for wheelchair (no push rim): 1.8kg / 3.96 pounds
• ½ inch bearings to fit standard ½ inch quick release axle pins (can be modified for 12mm axles)

Here are some articles about them: https://www.imeche.org/news/news-article/loopwheels-reinventing-the-wheel
http://www.bikeradar.com/gear/category/components/wheel-sets/product/review-loopwheels-20in-spokeless-suspension-wheel-13-47253/

SoftWheel Acrobat wheels

SoftWheel has production in Israel and is starting another in Europe and plan to start selling them in  2014 with pricing around $2,000 per pair. Just for the heck of it, I just sent them a message to see if it is possible to demo them.

• The Acrobat wheel can be adjusted to fit any wheelchair frame design
• The Acrobat provides 360° protection from impacts at any angle
• The Acrobat will take the hit for you

With our unique design, the Acrobat™ wheel delivers flexibility while preserving wheel functionality with no added energy loss and bouncy unstable sensation. On flat terrain it rolls like a rigid wheel and only when encountering impacts the suspension mechanism jumps into action to absorb the shock from the impact, lessening the stress to the rider’s body.

Option 2) Shock Absorbing Tires

There is a long thread about this Advice for best shock absorbing outdoor rear tires on CareCure Forums.

We want something that we can swap out easily without changing the dimension of his wheelchair too drastically. We do not want to add rear wheel spacing, or modify casters and brakes in order to use the tires.

We would prefer a “balloon” tire that is focused on shock absorption and decent puncture protection, even if it not as fast, light weight or maneuverable, because it’s primary use will be with a Firefly power handbike and it will not be self-propelled much.

We would like wide rims, between about 25C minimum and up to about 35C with decent shock absorption and weight. We would like to run high volume tires that are very low pressure, about 20 – 40 psi. We do not want too much tread, and would prefer them in black that will not leave skid marks if they need to be used inside.

We are looking for tires that are between 47-507 (24 x 1.75″) and 50-507 (24 x 2.00″) or 47-540 (24 x 1.75″) and 50-540 (24 x 2.00″). We would also like to go wider (55 or 60) with even more volume, but will probably have too much of a problem with swapping the wheels out because of rear wheel spacing. Although 590’s would be good for shock absorption, we think they would be far too large for the dimensions of the chair.

Converting to Shock Absorbing Tires

General Information

When converting from one size tire to another, many factors need to be considered. Tire tread, width, diameter, tire construction, tube type, the contact patch, and pressure all determine rolling resistance. On a wheelchair, camber also can affect how well tires preform, along with the relative low speed and the varied terrain and conditions they need to accommodate.

Just like with bikes, the dimensions of the wheelchair are also very important. Both the wheel and the tire need to fit the wheelchair and the intended use and abilities of the rider. For people who have a dedicated outdoor wheelchair with off-road and balloon tires, this can usually be figured out when configuring a chair. For others who need to use an everyday chair and swap wheels, it is a lot more complicated to convert to off-road and balloon tires.

I thought it might help to give a brief over of the most common sizes of rims and tires used for off-road and balloon tires on ultralight wheelchairs, because there is not a lot of information on the web except for on bike forums.

• 559 rims are known as 25 inch in the wheelchair industry, and 26 inch in the bicycle industry. 559 rims are often used by people who have a dedicated outdoor wheelchair with off-road and balloon tires. 590 rims are also sometimes used, but are not as common for off-road and balloon tires because they are so large and weigh a lot.
• 540 rims are known as 24 inch in the wheelchair industry. They are the standard for ultralight everyday wheelchairs, with 25-540 being the most common tire size for everyday use. 540 rims are often used by people who have a dedicated outdoor wheelchair with with off-road and balloon tires. For others like us, who want to use an everyday chair with off-road and balloon tires, this is the size we are trying to emulate so that we do not drastically change the dimensions of the wheelchair.
• 507 rims are known as 24 inch in the wheelchair industry, but in Europe they are sometimes known as 22 inch. This size wheel is difficult to find for wheelchairs, or they are low quality, and often people build their own with a wheelchair hub. 507 rims are relatively wide and ruggedly built, offering strength and stability, as well as being a good choice for a wider selection of tires. According to Sheldon Brown the applications are “Juvenile mountain bikes, BMX cruisers”.

Useful Links

Here are some good general links about the very confusing world of wheels, rims and tires:

• Schwalbe about: What do the various size specifications on bicycle tires mean?  How many tire sizes are there?  Which tire fits which rim? What is the exact circumference of my tire?  
• Wikipedia about Bicycle tires, Bicycle wheels
• Wheelchairjunkie.com about Off Road Wheels and Hybrid wheelchair tires.
• Sheldon Brown about Tire Sizing Systems (this is considered the “bible”) and Wheelbuilding.

Tire Sizing

ISO 5775-1: Bicycle tyres and rims — Part 1: Tyre designations and dimensions

This is what Sheldon Brown says about Tire Sizing Systems:

The ETRTO /  ISO system uses two numbers; the first is the width of the tire or rim in millimeters (The actual tire width will vary a bit depending on the width of the rim. The rim width is the inner width measured between the flanges as shown in the diagram.)

The second ISO number is the critical one, it is the diameter of the bead seat of the rim, in mm (“B.S.D.”). Generally, if this number matches, the tire involved will fit onto the rim; if it doesn’t match, the tire won’t fit.

A general guideline is that the tire width should be between 1.45/2.0 x the inner rim width.

If you flatten out a tire and measure the total width from bead to bead, it should be approximately 2.5 x the ISO width.

Rim Type and Size

ISO 5775-2: Bicycle tyres and rims — Part 2: Rims, defines designations for bicycle rims.

Most modern bicycle and wheelchair tires are clincher for use with “clincher” rims. These tires have a wire or Kevlar fiber bead that interlocks with flanges in the rim.These are usually  “hook” (also called “crochet”) designs to hold the bead of the tire in place.

The ISO 5775-2: Bicycle tyres and rims — Part 2: Rims designation for 24″ Spinergy LX and/or TiLite Out-Front Shadow rims are the following:

• Type: Spinergy LX’s are Crochet-type / hook edge (C). The other types are Straight-side (SS) or Hooked-bead (HB).
• Nominal width: The nominal width of the Spinergy LX rim is between 20-21C, This is the inner width between the straight sides or beads. Sheldon Brown calls this the “Inner rim width”.

This is the European Tyre and Rim Technical Organisation (ETRTO) publishes a guideline of recommended rim widths for different tire widths. Unfortunately, to does not go beyond 29C, but it gives an idea of the minimum and maximum tire widths:

This is a chart with comparisons of 26″ MTB tires the effect of rim width on tire size: Effect of Rim Width on Tire Width.  On the page from Sheldon Brown about Tire Sizing Systems he says:

Width Considerations

Although you can use practically any tire/rim combination that shares the same bead seat diameter, it is unwise to use widely disparate sizes.

If you use a very narrow tire on a wide rim, you risk pinch flats and rim damage from road hazards.

If you use a very wide tire on a narrow rim, you risk sidewall or rim failure. This combination causes very sloppy handling at low speeds…. Such narrow rims work very poorly with wide tires, unless the tires are overinflated…but that defeats the purpose of wide tires, and puts undue stress on the rim sidewalls.

Tire Dimensions

This Schwalbe page about converting to balloon tires says that balloon tires are not only wider, but also stand taller on the rim. They will change the rear seat height, and I need to see what the impacts are for that for not sliding out of the chair and the front caster angle.

I am not so concerned when we use them without the Firefly power handbike, which raises the front casters off of the ground, but there are times they will be used without it, and we don’t want him sliding out of the chair.

I made some rough calculations of the outside tire diameter for knowing how much different rims and tire size will affect the rear seat height compared to our Schwalbe Marathon Plus 25-540 (24 x 1.0″). The examples are a random selection of tires that we are considering. I used a simple calculation, because tire sizes vary drastically dependent on many variables, but this gives an idea:

• Wheel diameter (ø): = (rim diameter) + (tire diameter * 2)

These are the measurements of the Schwable Big Apples in similar sizes that were given by Schwalbe about converting to balloon tires:

Tire Pressure

This Schwalbe page about balloon tire advantages shows that they really would help with shock absorption. For us, much of the advantage for balloon tires is to be able to run them at the low pressure, so that we have the shock absorbing advantages. I can not find any information about what the minimum pressure should be based on 25C rims.

This chart shows the maximum pressure that Schwalbe reccommends for 25C rims:

Inflating to the lower number in the pressure range will tend to increase traction and make the ride more comfortable. Inflating to the higher number will tend to make the ride more efficient and will decrease the chances of getting a flat tire.

One published guideline for clincher inflation pressure is to pick the value for each wheel that produces a 15% reduction in the distance between the wheel rim and the ground when loaded (i.e. with the rider and cargo) compared to when unloaded.

Tire Volume

Courtesy of NW-Will in Advice for best shock absorbing outdoor rear tires on the CareCure forums.

Going from a 25-559 to a 60-559 on a 25mm wide rim… gives me a 600+% increase in air volume and the cushioning improvement didn’t make me think it was that great to warrant going the extra yard for the extra 35% of air.

Tire Tread

Tire Manufacturers

Tire manufacturers that sell wheelchair (WC) mountain bike (MTB) and bicycle motocross (BMX) tires include:

• Bontrager (part of Trek) MTB and BMX
• CST (part of  Cheng-Shin Rubber) MTB and BMX
• Maxxis (part of CST) MTB and BMX
• Continental MTB and BMX
• Hutchinson MTB
• Kenda WC, MTB and BMX
• Michelin MTB and BMX
• Schwalbe WC, MTB and BMX
• Specialized Bicycle Components MTB
• Tip Plus (Primo) WC and BMX
• GEAX (part of Vittoria)  MTB
• Vredestein MTB

Shock Absorbing Tire Options

Current 540 Wheels and New Tires

At least initially, we are looking at using the TiLite Shadow (540’s) wheels that we have because we would only need new tires. Because the primary use is for when using the Firefly handbike, which raises the front casters 2″ off the ground, I am not so concerned about the rear seat height.

• Will not require buying new rims, spokes, or hand rims.
• Will not have a problem getting these covered as as “maintenance” with the government.
• D’s Locks will be possible if we purchase the correct lockring adaptors.
• Risk that we have a problem with rear wheel spacing on both the ZRA and the 2GX.
• Risk that the rear seat height is too high. If running at low pressure, it should not increase the rear seat height too much.

Kenda Kobra K885

At ETRTO 50-540 (24 x 2.0″) they are wider, which should help with shock absorption. I have heard that they are not very long lasting, but they may be worth a try until we figure out a better solution, that will definitely cost more.

• They are higher pressure than we would like at 80 psi / 5.5 bar.
• I’m concerned that we might have a problem with the wheel spacing, because at 2″ there is only a 3 mm / .25 inch to the seat post.
• I’m also not sure what they will do to the rear seat height .
• They are knobby’s and we wanted more of a smooth tread
• They are grey with coloured sidewalls — we have green spokes, and it’s a bit of a clash aesthetically. I am also not sure that they are very strong, based on what others have said.

Here are the specs that I could find:

• Size: ETRTO 50-540 (24 x 2″)
• Type: Wired
• Protection: CAP Casing Added Protection (added layer of material under the tread area and runs from bead to bead)
• Color: Grey / red, blue or yellow sidewalls (we would get yellow)
• Weight: 1.00 lb/ 454 gram
• Pressure: 80 psi / 5.5 bar
• Article number: 252422885/20/25/30

Kenda Nevegal K1010

The photo is how they look mounted on Spinergy 24″ 540 wheels.

• I think this is going to be very slow rolling because it is a knobby tire with no connected center tread. We really don’t want knobbies, but there is not a big choice.
• I’m concerned about rear seat height because it will probably be quite high with these, especially because they are 54-540 (24 x 2.10″). The wider the tire, the taller it is.

The Kenda Nevegal is the optimal tire for an assortment of ever-changing terrain. It is highly adaptable and excels under various conditions, from loose rock, tall grass, muddy roots, single track and high speed descents, and many more.

• Size: ETRTO 54-540 (24 x 2.10″)
• Type: Folding
• Protection: CAP Casing Added Protection (added layer of material under the tread area and runs from bead to bead)
• L3R (Low Rolling Resistance Rubber Compound, increased tread life, and lower weight)
• Color: black
• Weight: ???  lb/ ??? gram
• Pressure: 50 – 80 psi / 5.5 bar
• Article number: 212186
• Available at Sportaid $58.50.

Schwable Airborne

At 30-540 (24 x 1.20″) I’m quite sure we will not have any problem with the wheel spacing on either the ZRA or 2GX, and I don’t think they will raise the rear seat height too much.

They are not knobby’s, quite strong, and they are black, and also I just like Schwable tires a lot. I also think we will have an easier time ordering them locally.

The are narrower than we would have liked and thus higher pressure than what we would like at 55 – 95 psi / 4.00 – 6.50 bar. Even when we run the Marathon Plus at their lowest pressure: 85 psi / 6.00 bar, they are still very bumpy.

• Size: ETRTO 30-540 (24 x 1.20″)
• Type: Folding
• Compound: Black’n Roll
• Protection: HD Speed Guard (Puncture protection level 5, same as V-Guard and GreenGuard.)
• Color: Black
• Skin: Lite
• Weight: 400 g (14 oz)
• Pressure: 55 – 95 psi / 4.00 – 6.50 bar
• Maximum load: 70 kg
• EPI: 67 (Ends Per Inch, Threads Per Inch)
• Article number: 11640408.02

Rubena V41 Walrus

I have not been able to confirm that this tire exists at this size.

City, touring, and trekking tire with great all season tread pattern. Optional Stop Thorn puncture protection (3.5mm thick flat prevention strip) and RS (Reflective Stripe with 3M Technology).

• Size: ETRTO 47-540 (24 x 1.75″)
• Type: Wired
• Color: Black
• Weight:??? g (???  oz)
• Pressure: ???.00 Bar (???  psi)
• TPI: 29
• Article number: ???

New 507 or 559  Wheels and Tires

I’m inclined to think that if we decide to get new wheels, it would be better to get 25/26″ 559 wheels, because there are a lot of choices in tires. Because he would not be using these on an everyday basis and need to transfer around them too much, the extra height should not be a big problem. Also, it was a size we considered, because he is quite tall.

• Will be a lower rear seat height with 24-507’s and higher with 25/26″ 559 wheels.
• We can try to purchase used 25/26″ 559 Spinergy wheels, but need to find someone willing to ship internationally, and it may be difficult to get covered by the government.
• If we get Spinergy 25/26″ 559 rims, we would be able to mount D’s Locks lockring adaptors if we find funding for them.
• Can also try to sell or swap TiLite Shadow wheels 25-540’s wheels, tires, rims to help fund them. TiLite (Out-Front) Shadow wheels MSRP $149.00, Primo V-Traks tires MSRP $54.00 / Sportaid $32.00, 24” 6-Pt Tab Silver Anodize rims MSRP $75.00.

Schwable Big Apple

Available as 50-507 (24 x 2.00″)  55-507 (24 x 2.15″) 55-559 (26 x 2.15) 50-559 (26 x 2.00) 60-559 (26 x 2.35)

Air suspension built-in. The Big Apple started off the Balloon bike trend ten years ago: Comfortable cycling without using complicated technology! Air cushion tires are used as natural suspension. Inflated to around 2 Bar a Balloon bike rolls really easily and with a full suspension effect. A normal tire with a width of 37 mm must be inflated to a rock-hard 4 bar, in order to roll similarly well.

• Size: ETRTO 50-507 (24 x 2.00″)
• Typ: Wired
• Compound: Endurance
• Execution: RaceGuard (Puncture protection level 4. A double layer of nylon fabric.)
• Color: Black-Reflex
• Skin: Lite
• Weight: 620 g (22 oz)
• Pressure: 2.50 – 5.00 Bar (35 – 70 psi)
• Maximum load: 100 kg
• EPI: 67 (Ends Per Inch, Threads Per Inch)
• Article number: 11100302
• Tube: ETRTO 50-507 24 x 2.00 AV (auto valve) 10 10421310

Schwalbe Big Ben

Available with RaceGuard as 55-507 (24 x 2.15) 50-559 (26 x 2.00) 55-559 (26 x 2.15) 60-559 (26 x 2.35)

Big Apple got a brother. The comfort is the same, but the Treade and the optics are clearly focused. Also available in the classic colors of cream, brown and grey.With ECE-R75 certification for fast E-bikes (55-406, 55-507, 55-559, 60-559, 55-622).

• Size: ETRTO 55-507 (24 x 2.15″)
• Typ: Wired
• Compound: Endurance
• Execution: RaceGuard (Puncture protection level 4. A double layer of nylon fabric.)
• Color: Black-Reflex
• Skin: Lite
• Weight: 700 g (25 oz)
• Pressure: 2.00 – 4.00 Bar (30 – 55 psi)
• Maximum load: 118 kg
• EPI: 67 (Ends Per Inch, Threads Per Inch)
• Article number: 11100555
• Tube: 54-507 24 x 2.10 (could not find 55-507) AV (auto valve) 10 1042131

This is the largest size available, and might be almost as good as a balloon tire, with the advantage of being very strong.

• Size: ETRTO 50-559 (26 x 2.00″)
• Typ: Wired
• Compound: Endurance
• Execution: SmartGuard
• Color: Black-Reflex
• Skin: Twin
• Weight: 1100 g (39 oz)
• Pressure: 2.00 – 5.00 Bar (30 – 70 psi)
• Maximum load: 118 kg
• EPI: 67
• Article number: 11100763

Continental Town & Country

I have heard good things about this tire for wheelchair use.

• police bike squadrons throughout the world use this tyre
• high mileage, puncture resistance, low rolling resistance

This tire performs well from city streets to country backroads. Inverted tread provides reliable traction with low rolling resistance. Ample air volume for comfort. Puncture resistant and long wearing.

• Size: ETRTO 47-559 (26 x 1.90″) also available as 54-559 (26 x 2.10″)
• Typ: Wired
• Color: Black
• Weight: 650g (??? oz)
• Pressure: ??? – ??? Bar (50 – 65 psi)
• TPI: 3/84
• Article number: 0122294

Continental Traffic

Bikes in the big city jungle.

• developed especially for daily MTB use in urban and rural terrain
• the central tread rolls fast and quietly on the road.
• also available with reflective strips for increased safety

The Continental Taffic is a mild tread design for pavement as well as gravel and light trails. Will provide grip and traction under all weather conditions.

• Size: ETRTO 47-559 (26 x 1.90″) also available as  50-559 (26 x 2.00″) and 54-559 (26 x 2.10″)
• Typ: Wired
• Color: Black
• Weight: 800g (??? oz)
• Pressure: ??? – ??? Bar (45 – 58 psi)
• TPI: 3/84
• Article number: 0100352

Maxxis Holy Roller

I have heard good things about this tire for wheelchair use.

• Inverted semi-knob design
• Dirt to pavement versatility

Our most versatile BMX tire – features a tightly spaced knob pattern. A unique design that rolls extremely well on pavement and still hooks up in hardpack conditions.

• Size: ETRTO 47-507 (24 x 1.75″)  50-507  (24 x 1.85″)
• Type: Wired
• Compound: Single
• Color: Black
• Weight: 525 g (???  oz)  and 610 g (???  oz)
• Pressure: ???.00 – ???.00 Bar (??? – 60 psi)
• TPI: 60
• Article number: M126

Maxxis DTH

Drop-The-Hammer BMX. I think this would be similar to Scwable Marathon Plus at low pressure.

• Light weight race tire
• Dual Compound Technology
• Foldable bead

The first few pedal strokes win the holeshot. The holeshot wins the race. Designed for the 2008 Beijing Games, the foldable DTH is super-light to accelerate like no other BMX tire, yet holds up to the abuse you dish out. The dual-compound tread corners incomparably on hard-packed tracks and rolls fast on the straights. The Gold Medal is just a sprint away.

• Size: ETRTO 44-507 (24 x 1.75″)
• Type: Folding
• Compound: Dual
• Color: Black
• Weight: 440 g (???  oz)
• Pressure: ???.00 Bar (??? – 65 psi)
• TPI: 120
• Article number: M147

Others to add

Bontrager (part of Trek) MTB and BMX

Hutchinson MTB

Michelin MTB and BMX

Specialized Bicycle Components MTB

http://www.specialized.com/nl/en/ftb/mtb-tires/recreational-mtb/roller

http://www.specialized.com/nl/en/ftb/mtb-tires/streetdj-tires

GEAX (part of Vittoria)  MTB

Vredestein MTB

Current 540 Hubs Rebuilt for 507 Wheels and New Tires

Buy new 24″ 507 rims, spokes and tires and rebuild with Shadow 24″ 540 hubs. The spokes are straight 14 gauge, 2.0mm commonly used for bicycle wheels. It is not possible to buy 24″ 507 Shadow rims. The problem is that the Shadow’s have a 30 spoke count hub, but most bike rims have 28, 32 or 36 spoke holes, so I don’t think this will work.  See Mismatched Wheelbuilding.

• D’s Locks might be possible if we purchase the correct lockring adaptors.
• Can probably have the wheels built locally at a bike shop.

Current 540 Hubs Rebuilt for 559 Wheels and New Tires

Buy new Shadow or Spinergy Wire 25″ 559 rims, spokes and tires and rebuild with Shadow 24″ 540 hubs.  (more information coming….)

• D’s Locks might be possible if we purchase the correct lockring adaptors.
• Can probably have the wheels built locally at a bike shop.
• Sportaid  sells  the complete Shadow wheels for about $253.30. Possibly also just the rims??? Probably Bike-on also sells them, because they carry other Out-Front products.
• Both Sportaid and Bike-on sell the complete Spingergy Wire wheels for about $235.00.

New Already Built 507 Wheels and Tires

Buy new already built 24″ 507 hubs, rims, spokes and tires in standard mountain bike configurations with a wheelchair hub. Probably much cheaper than labour costs to build a wheel with separately purchased hub, rims, spokes and tires. I am not seeing many wheels like this that are of a higher quality. Most use cheaper components.

Bergh Special Products  Spoked wheel Off the road

The price each is €125.34  (excl. 6% VAT). Price per pair is €250.68 / $339.28

• Size: ETRTO 50-507 (24″ x 1.95″)
• hub: alu black
• Ball bearing: 12 mm / .5 inch or 17 mm / 0.66 inch
• Rim: black
• Pushrim: alu black 6 p
• Tyre: black block profile, tube AV valve,
• Spokes: 36 spokes, stainless steel,crossed spoked,
• Hub length: 63/54 (bearing to bearing: 63 mm /  2.48 inch, overall 54 mm / 2.125 inch
• L.24195.22233Z11 (small axle)  or L.24195.22233Z12 (large axle)

Sportaid Off Road Wheelchair Wheels

Not sure of the wheel type. Available at Sportaid for $299.00

Looks to be a 36 spoke wheel. Not sure of the rim width or manufacturer.

Outdoor sports enthusiasts and anyone who wishes for additional traction for everyday wheelchair use have benefited from all terrain wheelchair wheels. This all terrain wheelchair wheel includes a Sun black double wall rim, black knobby tire, and six tab Aluminum handrim all standard. Vinyl or Foam coated handrim available. Note: This wheel takes a 25″ (559) tire. It is referred to as 26″ size due to the tires large profile.

• Size: ETRTO 55-559 (26 x 2.10″)

Sportaid Off Road Rear Wheels

Not sure of the wheel type. Available at Sportaid for $279.00

Looks to be a 36 spoke wheel. Not sure of the rim width or manufacturer.

There are multiple uses for all-terrain wheelchair wheels from outdoor sports to everyday use with added traction. When you can get a Sun black double wall rim, aluminum handrims, and a gray knobby tire with your all-terrain wheelchair wheel in one price, you go for it.

• Size: ETRTO 50-507 (24 x 1.95″) grey Kenda knobby
• Size: ETRTO 54-540 (24 x 2.10″) black Kenda Nevegal K1010
• Looks to be a 36 spoke wheel

Tween 24″ Tout Terrain (All Terrain)

They have the price listed as €225.00 / $304.00 per pair, which seems like an okay, but not great price, considering the parts.

Looks to be a 36 spoke wheel. Not sure of the rim width or manufacturer.

I had some confusion about the size, because they have it listed as  22″ on the website. A member of CareCure who has them confirmed that they are ETRTO 50-507 (24 x 1.95″).

He also confirmed that the Cheng Shin (CST) tires are similar to his Kenda Kobra’s with very small diamond head knobs on the middle, bigger and more aggressive knobs on the sides. They are easy to roll with minimal drag.

He also said that the Schwalbe Land Cruiser HS 307, which is an additional €24.00 / $32.50, has a slick band in the middle and moderate knobs, and thought it a very good choice too, and easier to push and more durable.

This is what I think the website says:

• A pair of wheels having the same outer diameter as a conventional 24″ rim with a Marathon Plus tire.
• Rim 22″ (usually considered 24″)
• Tire 22″ x 1.95″
• Black aluminum hand rim
• A pair of pins with a quick release axles attach to the wheels set on all chairs.

New 559 Fatbike Wheels and Tires

• I don’t think D’s Locks would be possible.
• Very expensive. Will have a problem getting these covered  as “maintenance/support” with the government.
• Will require purchasing wide rims and tires along with a hub and spoking the wheels.
• Wheels can be spoked using only one side of the spoke holes would give more wheel spacing.

This is a pretty extreme example of Wheelchair Clown Shoes, with Phil Wood & Co wheelchair rec. hubs laced on Surly Clown Shoe rims  topped off with 4.8 inch wide Lou rubbers!

Colours 540 Fatso  Wheels

Made for Colours Tremor wheelchair. At a price of  $1,284.00 (pair) it is not something we would consider. I think they are motorcycle wheels/rims that have been modified for the axle.

Designed with a one size fits most attitude, the “Fatso” wheelchair wheel assembly gives you the ability to transform your existing wheelchair into an off-road vehicle.

• Wheels made from aluminum alloy
• 24″ Diameter
• 8″ Wide
• Hub width at bearing faces is 2.25″
• Anodized Handrims
• 13.5 lbs. each
• Comes standard with foam coated handrims
• The minimum size for an Axel must be: Length 4 1/2″ – Diameter 1/2″. The length can be longer, but the diameter must be exactly 1/2″.

Surly Rolling Darryl

82mm wide single wall. Same 64 dual-spoke hole design as Marge Lite (now available in 72-hole for use with 36h hubs). This rim will increase the footprint of 3.8˝ tires compared to 65mm rims. Cutouts shave weight and allow your rimstrips to show through, which looks pretty cool we think. Note: Use of this rim will increase the width of your tire and may cause the chain to rub the tire in the lowest gears, so either remove a couple cogs and add some spacers behind the cassette or else get you an O.D. Crankset or some of our Mr. Whirly Offset Double chainrings. Available in 32-hole and seasonally 36-hole (without cutouts).

• Hub Compatibility: 32h & 36h hubs
• ETRTO*: 559mm
• Weight: 860g
• Color: Black, polished silver and limited edition seasonal variety.

Surly Nate 3.8

We named this tire for our friend Nate, who is himself large and aggressive. This tire has a shred-your-face-off, run-over-anything, kung fu grip knobby tread pattern. The casing is round and supple. Tall, widely spaced knobs are siped for added grip and compliance. The knobs’ wide spacing means they dig deep and still shed the crap you’re riding through. The tread is wrapped around the sides of the tire some, providing good knob contour even on very wide rims, which in turn allows good offcamber traction.

• ETRTO: 559mm (fits rims 50–100mm wide)
• Casing: 120tpi with Kevlar bead (1350g); 27tpi with wire bead (1730g)

Tire Instructions

Surly Black Floyd 3.8

Sometimes a lot of tread isn’t necessary. Sometimes, even on a fat bike,you don’t want to run real low pressure in your tires. Sometimes even fat bikes want to stretch their legs and run. Enter Black Floyd. Black Floyd allows you to pump up the pressure and cruise like a ’71 El Dorado. The casing is designed to work best on 65mm rims. The tread is comprised of tightly spaced low profile “bricks”. Naturally, it’s designed for street and hard-pack conditions. We expect the unicyclers will dig this one too. Your ideal pressure will vary according to what you want to ride, but in those places where less is more, Black Floyd will transform your fat bike into a road warrior.

• ETRTO: 559mm (fits rims 50–65mm wide)
• Casing: 60tpi with Kevlar (1050g)

Surly Larry 3.8

Larry is designed as a front tire for riding in snow, sand, mud and other loose or soft conditions. Its series of dart shaped knobs and tiny domes scattered among them combine traction and drift control. Designed around a 65mm rim, it will also retain good height and traction characteristics on 50, 82 and 100mm rims.

• ETRTO: 559mm (fits rims 50–100mm wide)
• Casing: 120tpi with Kevlar bead (1255g) 27tpi with wire bead (1635g)

New Build-Our-Own 507 Wheels and Tires

Buy new 24″ 507 hubs, rims, spokes and tires in standard mountain bike configurations with a wheelchair hub. (more information coming….)

Bike-on is probably a good source for us for components and kknowledge and have a Wheelbuild Pricing that lists components and gives an idea for pricing. Sportaid is probably also a good source.

See Center for International Rehabilitation Building the Rear Wheels

Hubs

The 24″ Shadow has an overall Hubshell Width of 2.5”, Hub Bearing Spacing of 2″ (outside-to-outside), with a Flush Bearing Face, and Outboard Bearing Recess of.5”. Axle Length 4”, Axle Diameter .5”.

The 24″ Spinergy LX has an overall Hubshell Width of 3″, Hub Bearing Spacing of 1.8″ (outside-to-outside), with an Inboard Bearing Recess of .5” and Outboard Bearing Recess of .7”. Axle Length 4”, Axle Diameter .5”.

• Phil Woods
• DT Swiss
• Bitex Wheelchair hub (DH12.7N). They have a distributor in Austria Bike & Sports HandelsgmbH.
• Sun Metal GT1000 Alloy wheelchair Hubs / Medium Flange from Sportaid $60.00
  

  The time has come for Sportaid to introduce you to Sun Metal GT1000 Alloy Wheelchair Hubs. These hubs feature a Medium Flange that measures 2″ providing a bearing width of 2.0″ from outside to outside. For 1/2″ quick-release axle 6061-T6 aluminum GT1000 Alloy Hub. Give your Sun Metal GT1000 Alloy Wheelchair Hubs 36 spoke holes and a hub body width of 2.5″ and make it stylish black, and you have a great looking valuable component to your transportation.

• Sun Metal GT1500 High Flange Hubs from Sportaid $69.00
  

  The Sun Metal GT1500 Hubs feature at 2.5″ wide hub body and measure 2″ from outside to outside bearing. Sun Metal GT1500 Hubs are meant for 1/2″ quick-release axle 6061-T6. The Aluminum GT1500 Hubs also have a High Flange of 3″ and 36 spoke holes. Sportaid can offer the best deals on Sun Metal GT1500 Hubs.

• Bergh Hub aluminum Ø50mm, black, for 36 spokes, axle hole Ø12mm / .5 inch, Hub length: 63/54 (bearing to bearing: 63 mm /  2.48 inch, overall 54 mm / 2.125 inch one side recessed S.NF.TOP.120.Z € 23,31
  
• Axles:  12 mm/ 1/2″  or 16 mm / 5/8″
• Spokes: probably 32 or 36 is the most common

Advice from Spinergy

I was able to get through to Spinergy about my question about rim type and size for Spinergy LX’s. Joe in service was very helpful and I wish I would have had more time to chat with him, because he was also very interested in what we are trying to do, and hinted that he hoped Spinergy would come out with more options for wheelchairs <service@spinergy.com>. He has worked with others using chairs, and understood the conundrums involved.

He also encouraged me to be in contact with Ryan Baker or Ryan Webb about it, and I hope to follow-up on that sometime soon. He did not give me these e-mail address’es, but i’m posting them just in case anyone else wanted to give some input: Ryan Webb <ryan@spinergy.com> Ryan Baker <livingspinal.sales@gmail.com>.

– Tire width/pressure: He felt the maximum we should go is 2.25, with a maximum of no more than 35 psi, and a minimum of about 27-30 psi. He made a good point that on tire pressure you loose about 10% just checking  with a pressure gauge and said that a Park or Schwalbe AirMax were good (digital are a bit better).

– Tube or tubeless: He really thinks tubeless are the way to go. He said we could probably run at 20-25 psi on tubeless, and recommended to get good sidewalls and use Stan’s NoTubes or Smart Tubes- Inner Tubes with Slime Inside (available in 507’s and 559’s). I have had my concerns about installation and maintenance, but am slowly starting to think that either may be a good way to go, with a preference leaning towards what he called “slime tubes”.

Option 3) Suspension Wheelchair

A rear suspension wheelchair is an option, but we do not have budget for a new wheelchair until 2020. Therefore, we will need to make do with other options.

Icon A1

We investigated getting an Icon A1. The Icon uses SRAM RockShox rear shocks for wheel suspension. Unfortunately we did not think we could make it work because the front frame configuration, and needing individual flip-up foot plates with enough room for foot propulsion. Also it was very new and just being introduced to the market at that time, and we felt that was a bit risky with a new chair.

The nice thing about the Icon is that it also very adjustable, and swapping wheels to have balloon tires would be less of an issue than it is for our TiLite ZRA, even though it also has many adjustments that can be made, it does not allow us to change the rear wheel spacing or rear seat height on the fly.

Is it possible for a wheelchair to be revolutionary? We think so. The Icon is adjustable to let you “dial-in” that perfect fit. You don’t need to worry about having to choose permanent specifications that can never be changed after a chair is built.

Your body and your needs are always changing. Your Icon’s geometry will change with you, ensuring a perfect fit right now, and for years to come.

Our suspension design allows it to be set to your exact weight. The compression and rebound can both be tuned to reduce fatigue and give you a custom ride over the bumps of everyday life. There is also a lock-out option for those times when you don’t want suspension.

The modularity of the Icon offers flexibility to change every component, including wheel sizes, and maintain the geometry that’s best for you.

The RockShox Monarch R air shock (205g, standard) as well as the Monarch RL (215g, upgrade) both adjust to match rider weight, and both have adjustable rebound (the rate at which the shock returns after compression). The R is 10g lighter than the RL, however, The RL adds the option for a remote lockout. Both are extremely durable air spring systems. The internal pressure is adjusted through a single Schrader valve, simplifying suspension setup while retaining the light weight and plush ride quality.

Oracing SX

The other suspension wheelchair that might be possible for the future is an Oracing SX. When we were looking for a new chair, we were not aware of it, or possibly it did not yet exist, but it will be on our radar for the future.

The SX is a cantilever style framed wheelchair with a difference. The chair incorporates a rock shox shock -absorber underneath the seat. This creates the ultimate in ride comfort with the shock absorber being adjustable to allow for different lengths of travel depending on your specifications. This chair is ideal for highly active users, including those that go off-road. It increases comfort when dropdownping  curbs and on uneven surfaces. It reduces vibrations through the body which may ease spasms. Combined with Frogs Legs Suspension Castor Forks this chair becomes a fully suspended smooth rider.

Other types of suspension

We also tried to get front suspension with Frog Legs Shock Absorbing caster forks (suspension forks) on his TiLite ZRA. Unfortunately, we could not get this configuration working with them, because they were interfering with the stability of the chair. See Front Forks / Casters.

In a perfect world, it would be great to have a suspension wheelchair, with both front and rear wheel suspension, and wide tubeless wheelchair rims/wheels, that we could run on a lower tire pressure for a smoother ride. If we had adjustability for rear wheel spacing and seat height along with front casters so they did not flutter, and preferably being also able to swap out front casters, it would be a great. For our application it would be perfect, but the cost is too prohibitive right now and swapping front casters is just not even possible as far as I am aware except on a Lasher Sport: BT-X.

Lastly, it was suggested that we get a Freewheel. We agree that this would help at some level, but not when using the Firefly power handbike, which will provide it’s own front suspension. This is something that we would have liked to have, but it was impossible to configure with the ZRA chair. See All-Terrain Third Wheel Options for more information about what we did not get and why, and what we are trying to do about front suspension for use with the ZX-1  Power Add-on.