Wheel size - why choose 24, 25, or 26?

[chasmengr]

I'm working on getting my first chair (hopefully a TiLite ZRA), and think I want a 26" wheel to reduce dump to 2.5". I can stand and walk/hobble a short distance, so I don't think I need lots of dump. And the chair is for everyday (not sports). How's my logic?

24" seems to be the standard. What trouble will I run into (or what flexibility will I lose) going to a 25 or 26? My environments are short-nap carpet, vinyl floors, pavement, and grass, so will 1" wide tires will be fine?

I searched the site and couldn't find info on this topic. If I missed it, please point me to an appropriate thread.

Thank
Chas
(MS T7 inc)

[canuck]

Think of the tire sizes as sort of gear ratios, 24" are better if you're climbing hills or ramps, they're easy to get rolling but you need to use more wheel strokes to cover the same distance as you would with 25" or 26" I've always had 24" up until I got my ZRA 6 years ago, now rolling with 25" they are great on flats once you get moving but they're a struggle when pushing up hills.

The reason 25" were suggested was because my wheel stroke wh 24" tends to make my forearms rub against the wheels.

I think for my next Ti-Lite I'll order 24" knobbies with it for winter/rough terrain use & keep the 25" for more urban/home use.

[SCI_OTR]

With a custom ultralightweight, "dump" is not strictly dependent on wheel size. It is the difference between the front and rear STF heights the chair is spec'd to be built to.

Your seat depth, front frame angle, and STF heights should be determined before you select your wheel size. You need to determine what height the front of the chair needs to be for you to come to a standing position and where your arms will be in relation to the push rims.

If you are thinking of an 85 degree frame angle, have a seat depth of ~16", and need a front STF higher than 19" in order to get out of it, having only 2.5" of dump would give the chair a high center of mass combined with a short wheelbase. Those characteristics can make a cantilevered rigid frame susceptible to endos, flipping backward, or position you with your hands too high for good bio-mechanical efficiency. I'm almost 6" tall and can also ambulate most of the time. I found that a high front STF height (20.5") combined with a lower rear STF height (16") gives me the height to stand up while maintaining a low center of mass and near optimal bio mechanical efficiency.

26" wheels would provide better pushrim access if both the front and rear STF heights are higher. However, they would also give the chair a larger footprint, could make mounting wheel locks difficult, be heavier than their 24 & 25" counterparts, and take up more room inside a vehicle.

I would sort out the other specs, then decide which wheel diameter works best for you.

It is all about finding the best combination of trade offs.

[flicka]

Don't forget to think about where your knees will end up, also. You don't want them too high to comfortably fit under tables & things like that.

[chasmengr]

I am currently using a borrowed Q2, which I've adjusted as best I could: with cushion, FSH=23; RSH=19.25 (would prefer 18.5, but chair won't go lower); seat size = 18x16; Camber = 4; lower leg = 18; rear wheel = Primo Orion 1.375x24 with inserts. Seat is a tad big. My hips are 16.25, so I plan to get a 17W seat. Also the cushion hits the back of my legs, so I plan to get 14 deep seat with a 17x15 cushion. (Will a Tempurpedic 16x16 fit a 17x14 sling?) I've removed the swing-away hangers from the Q2 so I can maneuver around my small apartment. But my thighs ache after awhile probably from the lack of a foot rest. I plan to get an 85-90 degree front end to mimic my current setup, but give me foot support.


So I think I've determined all the basic settings. I was considering a 26 rear wheel to decrease dump, but I hadn't thought about the 'gear ratio' concept nor the endo tendency. I've already found some tough grades with the 24s. So I think I'll order the 24s, and accept the dump.


You have given wonderful feedback. I'd sure appreciate more if you have it.

Thanks
Chas

[canuck]

Hills/ramps I've gone up with ease using 24" primo's can be a bit of a pain with the 25" tires, they're doable but at a much slower pace with more effort.

[Patrick Madsen]

Unless you are 6'4" and a basketball player, there is no need for 26" wheels. Most newbies go with the 24" for ease of pushing. Like Canuck and SCI said, wheel size does not determine dump.

I trust you are planning on any other chair than that of a Quickie. Perhaps look at the new Tilite ZRA series 2. If your DME is suggesting a Quickie it's because they can buy them really cheap, more profit for them.

With a 18" leg, you could go with a 20 or 21" fsh. your hips are 16.25 aand you want to go with a 17"? why, are you planning on gaining weight. It's a given fact that we eventually will fill the width of the chair we are in. Go with a 16" you are probably less than a 16 anyway. One of the reasons a person starts to lean to one side is because the chair they have is too wide so their bum slips to one side thus causing the lean.

A good rule of thumb for determining length of seat is two finger widths shorter than the back of your knee. If it's too long, the sling rubs the back of your knee; too short and you don't get the support thru the thighs.

As far as wheels go, it would really help knowing your height and level of injury. Are you active or not. dump is usually a way for we higher breaks to be more efficient when wheeling. For lower breaks, too much dump is more of a hinderance than help.

If the wheels are too big, like Canuck says, you can blow out your shoulders trying to push them.

[GL]

I have a question

Basically why not a quickie ? or a quickie GT or their GTi series ......
I am just curious
Thx
Sincerely;
Gypsylady

[TexasWheelz]

A lot of people just consider the Tilite chairs to be of much higher quality then the Quickie chairs. For me any way this is why I always recommend a Ti. I know when I was injured I wasn't even given an option, a Quickie GPV was what I got ordered for me, it was bright yellow and seemed cool compared to my hospital chair so I thought it was the best thing since sliced bread. My next chair was again a Quickie GPV because again I wasn't given any options and I thought it was either that or a hospital chair, again kick ass chair when comparing to the only other then I knew of. Same thing with my 3rd.

All 3 chairs had tons of issues with parts breaking, frame breaking on one...etc. But there was no internet, so I had no information in my little part of Oklahoma on other type of chairs. Then I saw a E&J Barricuda some where and thought wow, what a different type of chair. So I got it next and proceeded to break the frame twice in a year, loved it when it wasn't broke. Went back to Quickie, had more problems but still not given much options. By this time I had moved to a bigger city (Tulsa, Oklahoma) and was given a couple of options and ended up with a Invacare A4, which to me was head and shoulders above the Quickies I had previously used. Sadly I then moved to Amarillo and the place I went to for a chair only did Quickies, so again I had another GPV, however again it was a choice between a Quickie and a POS hospital type of chair, but after getting it I chose to use my old A4 again after month in that Quickie.

Thank God I was living in Dallas by the time I was able to get another chair and I finally was seeing what all was out there via the internet. I got a Ti ZRA and for the last 4 years have wondered how in the hell Tilite was kept hidden from me all that time and why DME's in all those other places I lived weren't selling them. It's such a huge difference in quality, ride, comfort then the Quickie's I had had that to me they don't even compare. Four years and the only problem I've had is a busted seat sling and that has more to do with my fat ass then anything else.

Now I realize that most DME's don't give a shit about us. They are just like a car dealership, they want to sell what is going to make them the most money. So if you don't already know what you want when you go to them, they are not going to put you in the best chair for you. They could get a Quickie(in my case it was always a GPV) for less then other light weight chairs and then keep a bigger % of the money they were given. The few other people I ran across in small town Oklahoma during this time were also in Quickies of various models.

I'll be honest, having a different model of Quickie might change my mind, the GT or GTi, the Q7 ...etc. are much different then the GPV, but I was never even given any other option for a chair. If you know how insurance coding works and then look at the prices for those different chairs you can see why.

Sorry to write such a rant on such a simple question, but after 5 or so Quickies that all fell apart on me within 3 years and gave me nothing but problems, this one Tilite has held together with no major issues for 4 years, which make me recommend the Ti over the Quickie every time.

[radio_buddha]

Shouldn't this be a question of the wheel plus the tire?

24-540 is smaller than 37-540.

I suggest you get used to the ISO numbers instead of 24, 25, 26. As Texas pointed out, more often than not, the wheelchair industry is your enemy. You'll need the ISO numbers to deal with the rest of the human race. Primarily, bicycle shops.

I did 24-540 for the reasons stated in this thread and it makes it easier for women to sit in my lap without their legs hitting the tread.

Sex, basically.