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Thread: How to choose wheelchair backrest angle?

  1. #1
    Senior Member sowseng's Avatar
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    How to choose wheelchair backrest angle?

    May I know how to decide how much backrest angle of a wheelchair user need? Thanks.

    Tilite ZRA and ZR price gone up so much.
    Life is meaningles, though you create the purpose.

  2. #2
    Quote Originally Posted by sowseng View Post
    May I know how to decide how much backrest angle of a wheelchair user need? Thanks.

    Tilite ZRA and ZR price gone up so much.
    Like most things it's personal preference. I find that with more upright position (my ZR2 has a fixed back angle set at 92 degrees) my posture is better and I get a more efficient push stroke. I experimented with increasing the angle on my ZR1 at the suggestion of my seating therapist because it lessened my seating pressure. However, with the back reclined further I wound up having to bring my shoulders forward more to compensate for balance AND I had a weaker/less efficient push stroke. I later returned the angle back to a more upright position.
    Last edited by stephen212; 02-16-2012 at 10:58 PM.

  3. #3
    Senior Member sowseng's Avatar
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    How about the guide in Tilite oreder form?

    " Measure angle from front of back post to floor. 90° will be perpendicular to the floor. To approximate the angle from the back post to the seat, subtract 2 degrees from measurement (G) for every 1/2” of dump."
    Life is meaningles, though you create the purpose.

  4. #4
    Quote Originally Posted by sowseng View Post
    How about the guide in Tilite oreder form?

    " Measure angle from front of back post to floor. 90° will be perpendicular to the floor. To approximate the angle from the back post to the seat, subtract 2 degrees from measurement (G) for every 1/2” of dump."
    Not sure exactly what you're asking. TiLite's measurement guide isn't attempting to offer suggestions to find a user's ideal back angle. The angle measurement on the order form measures the back posts relative to the floor. I've never concerned myself to calculate the angle formed at the vertex of the seat and the back posts, which of course is adjustable unless you're specing a fixed back chair.

  5. #5
    Quote Originally Posted by sowseng View Post
    How about the guide in Tilite oreder form?

    " Measure angle from front of back post to floor. 90° will be perpendicular to the floor. To approximate the angle from the back post to the seat, subtract 2 degrees from measurement (G) for every 1/2” of dump."

    Depends level of injury and backrest high.

    Just go for 90º, if is for lower backrest(less than 12") and for guys who have abs, even for guys like me with abs, a higher backrest with 90º is not confortable.

    I`ve got a 11" welded backrest to 90º.

    But for almost all guys works 92º and for some quads prefer 95º.

  6. #6
    Senior Member sowseng's Avatar
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    " Measure angle from front of back post to floor. 90° will be perpendicular to the floor. To approximate the angle from the back post to the seat, subtract 2 degrees from measurement (G) for every 1/2” of dump."

    So according to the statement in Tilite order form above, if I want a 90° backrest for 1" dump, I shall choose 88° right?
    Life is meaningles, though you create the purpose.

  7. #7
    Quote Originally Posted by sowseng View Post
    " Measure angle from front of back post to floor. 90° will be perpendicular to the floor. To approximate the angle from the back post to the seat, subtract 2 degrees from measurement (G) for every 1/2” of dump."

    So according to the statement in Tilite order form above, if I want a 90° backrest for 1" dump, I shall choose 88° right?
    If you want to calculate the angle from the seat frame to the backrest frame using TiLite's approximation method:
    Angle = <specified angle>-(FSH-RSH)/0.5"x2deg = <spec angle>-(FSH-RSH)x4

    for example:
    if FSH=19", RSH=18", & spec angle=90 then 90-(19-18)/0.5x2 = 90-1/0.5x2 = 90-4 = 86
    if FSH=17.5, RSH=14.5, & spec angle=90 then 90-(17.5-14.5)x4 = 90-12=78deg (my chair)

    Personally, I ignore my backrest-to-seatframe angle (78) {in fact I didn't even know it until just now}, and pay attention only to the backrest-to-floor angle (90). Click the AeroZ link in my signature to see pictures.

    (The real formula is trigonometry:
    backrest-to-seatframe angle = <spec angle>-arcsin((FSH-RSH)/seat length), which for my chair yields 90-arcsin(3/16)=79 degrees, which is more accurate than TiLite's 78, but very close.)
    Chas
    TiLite TR3
    Dual-Axle TR3 with RioMobility DragonFly
    I am a person with mild/moderate hexaparesis (impaired movement in 4 limbs, head, & torso) caused by RRMS w/TM C7&T7 incomplete.

    "I know you think you understand what you thought I said, but what I don't think you realize is that what you heard is not what I meant."
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    UNKNOWN AUTHOR>

  8. #8
    Go with totoL1's suggestion. Welded at 90° and 10 or 11 inches. It's very important to have an angle adjustable shell like the ADI 2 Point Pro.

    Adjustable back post is just crazy. The changes in configuration are drastic. Get it fixed and make sure the shell is adjustable.

    Users need to make small changes to the back, not big ones.

    At 11 inches, you can probably go as far up as 14 or 15 inches with the shell. I doubt you'll want that much height based on what I've seen of you on youtube.

    Why a titanium chair? Aluminum will survive Malaysia's climate. I'm back to aluminum in South Florida. Cheaper and you can get more extras (2 point pro, good wheels, etc.) for the same amount of money of a standard titanium with no extras.

    And then there's the Icon. Have you checked that out?

  9. #9
    Senior Member sowseng's Avatar
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    Quote Originally Posted by chasmengr View Post
    If you want to calculate the angle from the seat frame to the backrest frame using TiLite's approximation method:
    Angle = <specified angle>-(FSH-RSH)/0.5"x2deg = <spec angle>-(FSH-RSH)x4

    for example:
    if FSH=19", RSH=18", & spec angle=90 then 90-(19-18)/0.5x2 = 90-1/0.5x2 = 90-4 = 86
    if FSH=17.5, RSH=14.5, & spec angle=90 then 90-(17.5-14.5)x4 = 90-12=78deg (my chair)

    Personally, I ignore my backrest-to-seatframe angle (78) {in fact I didn't even know it until just now}, and pay attention only to the backrest-to-floor angle (90). Click the AeroZ link in my signature to see pictures.

    (The real formula is trigonometry:
    backrest-to-seatframe angle = <spec angle>-arcsin((FSH-RSH)/seat length), which for my chair yields 90-arcsin(3/16)=79 degrees, which is more accurate than TiLite's 78, but very close.)
    Thanks, chasmengr, when I order my GTi, the backrest configuration is very simple. So the Tilite backrest configuration is new to me.
    Life is meaningles, though you create the purpose.

  10. #10
    Senior Member sowseng's Avatar
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    Quote Originally Posted by radio_buddha View Post
    Go with totoL1's suggestion. Welded at 90° and 10 or 11 inches. It's very important to have an angle adjustable shell like the ADI 2 Point Pro.

    Adjustable back post is just crazy. The changes in configuration are drastic. Get it fixed and make sure the shell is adjustable.

    Users need to make small changes to the back, not big ones.

    At 11 inches, you can probably go as far up as 14 or 15 inches with the shell. I doubt you'll want that much height based on what I've seen of you on youtube.

    Why a titanium chair? Aluminum will survive Malaysia's climate. I'm back to aluminum in South Florida. Cheaper and you can get more extras (2 point pro, good wheels, etc.) for the same amount of money of a standard titanium with no extras.

    And then there's the Icon. Have you checked that out?
    Consider a second chair, one put in the car, and the another one for home use, then I don't need to transfer my chair every time I drive or when I am home.

    I still consider full welded aluminium or titanium chair, because I want to travel with it too. For those adjustable chair, I think it is too risky for the worker to throw in and out the plane together with so many passenger's luggage. For fully welded aluminium chair seems to be much expensive than ZR.

    I have friend whose chair was broken during the fright.
    Life is meaningles, though you create the purpose.

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