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Thread: World's Lightest Wheelchair Wheels

  1. #11
    Quote Originally Posted by 1029xx View Post
    Lighter and cheaper than Topolino, Spinergy, Golz, Dinos...
    http://www.tiarrow.com/?product=sweel

    Thoughts?
    Look closely at their chart. It is deceptive since the baseline does not start at zero. There is only a 0.4 lb difference between Sweel and Spinergy, that's 6 ounces. I would stay with the Spinergy products.
    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.

  2. #12
    Quote Originally Posted by nonoise View Post
    Look closely at their chart. It is deceptive since the baseline does not start at zero. There is only a 0.4 lb difference between Sweel and Spinergy, that's 6 ounces. I would stay with the Spinergy products.
    Yes, the static weight is 0.4 lbs which is 0.8 lbs for a pair which equals 3.2 lbs when you roll around (since it's rotating mass, discussed earlier in this thread). 3.2 lbs all day everyday adds up.

    You only have two shoulders in a lifetime. To me that's reason enough to care about this kind of products.

  3. #13
    Senior Member canuck's Avatar
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    Looks like they also make some good looking chairs if you prefer a more box style then a open frame.

  4. #14
    Senior Member Oddity's Avatar
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    Quote Originally Posted by 1029xx View Post
    I think it's great if you're happy and think you found some kind of sweetspot between function, durability and lightness.

    However, I really can't see anything wrong about getting light wheels. In particular these TiArrow wheels that's cheaper than everything else in it's class. To me, it seems like a win-win situation.

    I agree. We all need to find what works best for our given situations (including budget), setups, and seat-of-pants feedback.

    Since you mentioned the "physics" of the situation, and you seem to know something, can you entertain a few more questions?

    For a cylinder, MoI (moment of inertia) is going to be as dependent on the location of the mass relative to the axis of rotation as total mass. All else being equal, less mass = lower MoI, but where the mass is located affects the feel quite a lot. A slightly heavier hub + light rim can feel easier to rotate than a heavier rim + light hub.

    I point this out simply to support the notion that focusing on weight/mass as the goal can be misleading. Where the mass is located relative to the axis matters too, if not more.

    Also, we're talking about MoI, aka acceleration. Momentum is another thing, and is actually compromised by lower rotational mass. A cylinder that requires more energy to overcome the moment of inertia conserves more energy while rolling. Right?

    So, here are my questions:

    Do you know how the mass of the Sweel is distributed differently along the rotational axis than a Spinergy LX, or other competitors?

    ...and...

    Any ideas as to the effect (in terms of, say, push strokes required to maintain a given pace over a given distance) that lowering the rotational mass of a wheel has on our pushing experience?

    Accelrating easier is good, in and of itself, but pushing more to maintain a given pace may not be, from a repetitive stress point of view.

    FWIW, I still think there's more to this "equation" than weight, although I do appreciate the product for what it is, and what it is trying to represent.
    "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

    "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

    "Even what those with the greatest reputation for knowing it all claim to understand and defend are but opinions..." -Heraclitus, Fragments

  5. #15
    Senior Member Oddity's Avatar
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    Quote Originally Posted by canuck View Post
    Looks like they also make some good looking chairs if you prefer a more box style then a open frame.
    Indeed, they do! Reasonably priced, too. I'm definitely intrigued.
    "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

    "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

    "Even what those with the greatest reputation for knowing it all claim to understand and defend are but opinions..." -Heraclitus, Fragments

  6. #16
    Senior Member canuck's Avatar
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    Could be in for a surprise on the pricing as they are located in Europe so I don't think that pricing is in U.S. Dollars.

  7. #17
    Oddity: I was an elite cyclist before my accident so wheel weight was something I've experimented much with. Most competetive cyclists love to do that since it affects the cycling performance a lot.

    You're absolutely right about the importance of weight distribution. The weight of the rim is definitely more important than the hub weight. The description on the TiArrow site says that they got the world's lightest aluminum rim in this wheel, which is very impressive considering the flora of bicycle rims out there. So should be very good distribution wise.

    When it comes to everyday wheelchair usage it's all about acceleration. For the majority of people most pushing is done indoors which means lots of starts and stops. Outdoors this effect is most noticable when you're going uphill. Regarding the idea that a greater amount of inertia would be something good (it's called the flywheel effect) that's mostly just true when you do declines. But as soon as you get to a incline where it gets a little bit harder it's always better with lightness to conquer gravity.

    In short - unless you're only going downhill with your wheelchair you should always strive against having as light wheels as possible.

    This site has a lot of formulas to count for different scenarios and calculate to see the importance of wheel weight. It's a lot of fun if you're as geeky as me regarding these things...
    http://www.analyticcycling.com/

  8. #18
    Quote Originally Posted by canuck View Post
    Could be in for a surprise on the pricing as they are located in Europe so I don't think that pricing is in U.S. Dollars.
    I think it is U.S. Dollars if you click on the american flag in the top on the site. The prices gets different and currency symbols changes if you choose GB or EU.

  9. #19
    Senior Member Oddity's Avatar
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    That is a cool site! I was heavy in to 2-wheeled sports prior to my injury as well, although of the motored variety. I was a "never gonna make it Valentino Rossi wanna-be"! Yes, hopefully their claims of being the lightest are actually in the rim itself and not mostly on account of the carbon fiber hub.

    re: the flywheel effect, that comes into play on the flats, too, where it helps maintain more forward velocity between push strokes. But, I think it's true we are always either decelerating or accelerating, never actually maintaining a truely steady velocity, in absolute terms. And at the price I think these wheels are a great addition to the market. I admit to having a bit of a grudge against the "weight is the priority" manufacturer marketing hype because a lot of it is down right misleading. Such is the way of marketing in general, I reckon!

    Quote Originally Posted by 1029xx View Post
    Oddity: I was an elite cyclist before my accident so wheel weight was something I've experimented much with. Most competetive cyclists love to do that since it affects the cycling performance a lot.

    You're absolutely right about the importance of weight distribution. The weight of the rim is definitely more important than the hub weight. The description on the TiArrow site says that they got the world's lightest aluminum rim in this wheel, which is very impressive considering the flora of bicycle rims out there. So should be very good distribution wise.

    When it comes to everyday wheelchair usage it's all about acceleration. For the majority of people most pushing is done indoors which means lots of starts and stops. Outdoors this effect is most noticable when you're going uphill. Regarding the idea that a greater amount of inertia would be something good (it's called the flywheel effect) that's mostly just true when you do declines. But as soon as you get to a incline where it gets a little bit harder it's always better with lightness to conquer gravity.

    In short - unless you're only going downhill with your wheelchair you should always strive against having as light wheels as possible.

    This site has a lot of formulas to count for different scenarios and calculate to see the importance of wheel weight. It's a lot of fun if you're as geeky as me regarding these things...
    http://www.analyticcycling.com/
    "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

    "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

    "Even what those with the greatest reputation for knowing it all claim to understand and defend are but opinions..." -Heraclitus, Fragments

  10. #20
    I recently inquired about shipping charges on these wheels. They told me shipping to the U.S. was around $110.

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