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Thread: Occasional use off-road wheels on a budget???

  1. #11
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    Quote Originally Posted by baldfatdad View Post
    How about this. Make a chair out of PVC. Use a piece of steel rod for an axle. Get both rear wheels and front caster wheels from Harbor Freight.com. Probably throw the whole thing together for less than a $100, maybe $50. That way you leave your street chair alone.
    That might work, but it seems a bit clunky to me... I also suspect that it would end up bigger and heavier than my street chair - given that I'm already on the hefty side, I want to keep life easy on the volunteers...

    Also I have a second arguably more scary project in mind.... The Artisan's Asylum where I spend a lot of my time is also the home base of "SCUL" the friendly Somerville Bicycle Chopper Gang - a quite colorful group that goes out on "missions" (group rides) every Saturday night during season. They want to take me along with them, with the plan being to try and turn my manual chair into a trailer that they can haul behind one of their tandem bikes - design already exists on paper, and is at least consistent with existing bicycle trailer designs - and will be tested carefully before doing any distance.... A PVC chair would definitely NOT work for that!

    I have found some more relevant data, partly from the Sheldon Brown website (one of the definitive sources for bicycle tech, according to all sources I've asked) and partly from checking out the chairs other folks were using on an adaptive rock climbing trip to the "Gunks" we just was on...

    Per Sheldon's site, http://sheldonbrown.com/tire-sizing.html there are a BUNCH of different bicycle tire sizing "standards" that have been used by different countries, bike brands and so on, most of which actually have little to do with the actual size of the RIM that a tire goes on, and which are NOT compatible... To fix this there is a new standard "ETRTO" that is a metric sizing system that is based on the diameter of the rim.

    Per the linked article, MOST wheelchairs use an ETRTO rim size of 540, and a traditional size of 24 x 1 3/8" E-5, (there is also a Schwin S-5 size that's different) which translates to ETRTO size 37-540. The first number in the ETRTO system is the approximate inflated diameter of the tire, and the second is the actual diameter of the rim's bead seating diameter. I measured my rims with the usual generic "Orion Primo" grey 24 x 1 3/8" tires at almost exactly 24" / 610mm, I also have a pair of SPOX wheels with Mako KIK solids on it, which are 24x1 nominal size, and are 588mm / 23 1/8" OD. Since I use the SPOX wheels most of the time, I'd like the replacement wheels to be around the same size.

    There is an ETRTO size that uses a 507mm rim, and uses the DECIMAL tire sizes 24 x 1.5" to 24 x 2.125" which are usually found on Juvenile mountain bikes and cruisers.... (Note that the decimal size tires are NOT the same rim size as the equivalent fractional sizes!)

    The old sizes sort of described the tire WIDTH by it's approximate inflated OD, with emphasis on the "approximate" part.... In most cases, the tire height above the bead seats is about the same as the width... So if one translates the decimal 1.5" - 2.125" to metric 38.1mm - 54.61mm, doubles it and does a bit of rounding you get about 80-100mm - added to 507, gets about 590 - 610mm.... This is the just about the same ID as my existing wheels....

    As further practical evidence, one of the other wheelers on the Gunks trip had wide mountain knobbies on her chair - I didn't have a tape with me, but parking next to her, I found her wheels were about the same size as my 24x1 3/8" tires or a bit smaller. They were marked on the tires as 24 x 1.95" ! So it looks like I have found a rim solution, Now all I have to do is find some appropriate ETRTO size 507 rims the right width and with 30 spoke holes to match my existing hubs....

    ex-Gooserider
    T-5 ASIA-B para, currently working on building own power chair, as being in a manual is an EXTRA handicap.

  2. #12
    Senior Member ~Lin's Avatar
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    Standard 24" wheelchair wheels are 540 wheels and can fit anywhere from 1-2" (25-50) tires depending on width. 25" wheelchair wheels are 559, which is actually what 26" mountain bike wheels are. Yes, you always want to use ERTO when matching up tires and wheels. I have a set of 540s with 25-540 right runs, and a set of 559s with marathon plus in 25-559. There are other individuals here who use 507 wheels for wider off road tires.
    Board Member of Assistance Dog Advocacy Project working in Education. Feel free to ask me any service dog questions!

    I am not paralyzed. I have a genetic connective tissue disorder with neuro complications and a movement disorder.

  3. #13
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    Thanks for the confirmation, and added info.

    To me, the biggest appeal of the 507 wheels is that they allow super wide tires, which will give better traction on rough ground, and that the finished wheel will be about the same size as my indoor wheels, so I (hopefully) won't need to do anything with my brakes when swapping the wheels. (I might consider making a set of "adapter blocks" to change the brake spacing without needing to adjust the brakes otherwise...)

    My plan is essentially to have the chair set up for indoor use, since that is 99% of what I do with it, but then have an "outdoor kit" with all the parts I need to switch over to the outdoor configuration in 10 minutes or less, using few or no tools, and without needing to make any extra adjustments...

    ex-Gooserider
    T-5 ASIA-B para, currently working on building own power chair, as being in a manual is an EXTRA handicap.

  4. #14
    Senior Member ~Lin's Avatar
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    If you want to look up elarson's thread about trying to get suspension through tires, there is discussion about using 507's for outdoors.

    I'm not sure if that would work with the brakes, since slight differences in tire tread or height can be an issue. However if you went with hub locks and had discs for different wheels you'd never have to worry about adjusting brakes again. Depends on if the cost is worth it for what you want.
    Board Member of Assistance Dog Advocacy Project working in Education. Feel free to ask me any service dog questions!

    I am not paralyzed. I have a genetic connective tissue disorder with neuro complications and a movement disorder.

  5. #15
    Check out the new Fatso: http://www.livingspinal.com/Fatso-Of.../col-fatso.htm It appears to be coming with the axle and the ad says it's sized to swap out with a chair having 25 inch rear wheels. I don't know what your budget is, but these look good. That said, I liked the photos of the older ones because they looked even fatter and more soft sand worthy and I am hoping used ones start to go on the market now that these are out. I had to get carried off the beach my last time out because I was in a regular chair.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  6. #16
    Senior Member ~Lin's Avatar
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    I've wondered about having some wheels built, talked to the local bike shop. If you bring everything in they only charge 35 to build and true them. So I've got spokes and hubs, and just need a wider rim lol. But then comes in having to get it drilled for handrims.... I haven't seen the exact size wheelchair rim I'd want, and of course they're so much more expensive than bicycle ones. Guess I'll have to find out if the upcharge is worth it compared to getting handrims put on. At the same time I want to get a set of those taiwan wheels and matching casters some day, the price is 407 for a pair of rear wheels with 100-125 for shipping to the US, I'm waiting to find out the price for just the wheels and no handrims or tires since I use natural fits. Someday... haha.
    Board Member of Assistance Dog Advocacy Project working in Education. Feel free to ask me any service dog questions!

    I am not paralyzed. I have a genetic connective tissue disorder with neuro complications and a movement disorder.

  7. #17
    Maybe something like this could be fabricated.

    http://www.melrosewheelchairs.com/

  8. #18
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    Well the new Fatso's are totally budget busters as far as I'm concerned... I'm looking more at a budget of $1-200, doing most of the work myself... (I have access to people with expertise on building / truing wheels and tools if needed...) In addition the idea of tubular pushrims is a total non-starter as far as I'm concerned, as Natural Fit rims are so much better. That said, I'm not planning to put ANY pushrims on the outdoor wheels - I will be wearing gloves anyway, so pushing on the tires isn't a big deal, and besides volunteers will be doing a lot of the pushing..

    Speaking in more general terms, I think it's an incredible ripoff what we get charged for wheelchair wheels when compared to the cost of pedal bike wheels....

    I'm also not going to do hub locks for the same reason - not to mention the extra weight...

    In terms of making something, those Melrose chairs look cool, but seems to me like they would be more in the way than anything for off-roading, as those guards make the footprint bigger... They certainly would have been a problem for the crew that was helping to get me to the climbing crags on Crow Hill... It was hard enough finding a way to get my minimal framed Quickie Q-7 over the rocks...

    Totally an "other person propelled" approach, but at the Boston Abilities Expo they had an Italian tourism outfit that had a neat all-terrain approach - essentially a sedan chair with a single central wheel directly under the seat / center of gravity, with stretcher handles and shoulder straps on the front and rear. The claim was that this allowed HP access to all the pre-ADA Italian historical / scenic sights with less hassle than with a standard manual chair (forget about doing it in a several hundred pound power-chair...) Would be a nice solution for those situations where you are dependent on AB assistants to get where you are going...

    ex-Gooserider
    T-5 ASIA-B para, currently working on building own power chair, as being in a manual is an EXTRA handicap.

  9. #19
    I suggested Fatso's just as I browse the second hand cast offs. It is amazing some of the extra ordinarily low prices that come up on Craigslist. As for brakes, it shouldn't slip away too fast with soft tires anyway.
    On the other hand...I think you did not see the right wheels in the Melrose link. Look at these X-Wheels:
    [TABLE="width: 700, align: left"]
    [TR]
    [TD="width: 220"] [/TD]
    [TD="width: 20"][/TD]
    [TD="width: 460"]Melrose X-Wheels[/TD]
    [/TR]
    [/TABLE]
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  10. #20
    Well that is a surprise. I copy pasted Melrose X-Wheels and got the picture instead, cool. So looking at that picture, a year ago I tried to build something like that out of composite (the cheap plastic) wheels hooking them up side by side. Some things don't work out. Ah, many things don't work out.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

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