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Thread: Oracing combines carbon fiber and titanium in a new way

  1. #11
    Senior Member wheeliecoach's Avatar
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    Quote Originally Posted by Black Alloy View Post
    The consequences of eliminating the bracing between the caster housing and camber tube are plenty. Just sitting on a cantilevered frame won't be a problem, but once you start to move it, the problems begin.

    I am interested in this comment...since there are many of us that are sitting in these types of frames...myself included. I have not had any problems with this frame...and I love the ease of transfer and how minimal it looks. What consequences are you talking about? I have had a chair like this for over 4 years and never once had an issue.
    "Unless someone like you cares a whole awful lot nothing's going to get better. It's not." - Dr. Seuss

  2. #12
    Titus started building mountainbikes with the same idea back in 2005. They called it exogrid but it has never really caught on and has been more of a novelty item. It saves a bit of weight and allows for them to tune the rigidiity of different tubes a bit for hardtail use but it basically just look cool. They laser cut the titanium tubing and insert a carbon sleeve.

    http://www.on-one.co.uk/news/product...9er-prototypes

  3. #13
    wheeliecoach,

    Without lower bracing the caster housing assembly has much less support and the welds/brackets would be more likely to fail. Especially welded aluminum. Titanium stands a better chance of holding up over time when used in that scenario, particularly in the welds. Using a bolted on caster housing could offer more strength, but the tradeoff would be weight.

    The frame as a unit is also likely to be much less rigid, especially in twisting.

    If you like the way they look, that's certainly a consideration. They won't fit in any smaller box than a standard frame, so space savings is negligible.

    I'm not trying to scare anyone from using one, I just don't think they provide any advantage IF built AS strong as a box frame.

  4. #14
    or you could just do like I am and have your frame hydro dipped to look like carbon fiber
    Life's perceived journey in this PMR is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "holy **** what a VR ride!"
    Pete C6/'97

  5. #15
    Quote Originally Posted by Black Alloy View Post

    The frame as a unit is also likely to be much less rigid, especially in twisting.

    That is exactly the reason I'll never go back to a cantilever frame (only had one of 'em.) After using a box frame, the canti feels like a wet noodle.

    As for the carbon/titanium conundrum... Personally, I don't think carbon is a good material for everyday wheelchairs. Does anyone remember the all-carbon Quickie that was around several years back? Most everyday chairs get a lot of bumps and bruises. Carbon just doesn't stand up well to that kind of use. The main reason to blend carbon and titanium would be for aesthetic purposes. I remember working on a high-end Merlin road bike that had a creaky frame! The noise was coming from one of the titanium lugs that had a carbon tube going into it.

  6. #16
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    Quote Originally Posted by The_Wheel_Life View Post
    As for the carbon/titanium conundrum... Personally, I don't think carbon is a good material for everyday wheelchairs. Does anyone remember the all-carbon Quickie that was around several years back? Most everyday chairs get a lot of bumps and bruises. Carbon just doesn't stand up well to that kind of use. The main reason to blend carbon and titanium would be for aesthetic purposes. I remember working on a high-end Merlin road bike that had a creaky frame! The noise was coming from one of the titanium lugs that had a carbon tube going into it.
    CF when designed and used properly is superior in every way. That's why it's used in F1, Indycar, Nascar. Just about every type of high performance sport. And they don't go kid gloves on their CF parts.
    ---------
    C5-6 / '88

  7. #17
    Quote Originally Posted by Reed-edm View Post
    CF when designed and used properly is superior in every way. That's why it's used in F1, Indycar, Nascar. Just about every type of high performance sport. And they don't go kid gloves on their CF parts.
    As CF becomes more prevalent in future wheelchair designs (an assumption on my part) how will first generation consumers assess whether the CF was designed and used properly?

    What's your take on the Panthera-X? A friend of mine bought one recently and I learned that the rim on the custom Spinergy wheel exclusive to the Panthera-X cut severely bent while he was dropping off a curb. He's also reported a failure of the one-lever wheel lock system.

  8. #18
    Mountain biking is going through the same process right now. Back in the 90's they built some terrible cf frames that were way too lite and failed which gave it a terrible reputation. The new frames are way superior and pretty much all have a sacrificial cosmetic outer layer that takes the scratches and chips without affecting the underlying strength. I road cf bikes exclusively the last couple years and they took 100 times the abuse any of my chairs ever will with no failures whatsoever. Loading and unloading a chair isn't the same as pitching a bike down a rock chute as far as impact and abrasion. Any crash that destroys a well built cf frame would have destroyed an aluminum frame faster.

    If you want to see some clear measured and documented demonstrations of the superior strength and toughness of a cf frame read this article and watch the first video to the end where they smash a cf frame into a concrete block without any damage.
    http://www.pinkbike.com/news/santa-c...-test-lab.html

  9. #19
    Quote Originally Posted by The_Wheel_Life View Post
    That is exactly the reason I'll never go back to a cantilever frame (only had one of 'em.) After using a box frame, the canti feels like a wet noodle.
    .
    You are a bit exaggerate lol, but yes, that usually happens, people that try box frames, usually never go back to cantilevers again.

  10. #20
    Quote Originally Posted by gmorris View Post
    Mountain biking is going through the same process right now. Back in the 90's they built some terrible cf frames that were way too lite and failed which gave it a terrible reputation. The new frames are way superior and pretty much all have a sacrificial cosmetic outer layer that takes the scratches and chips without affecting the underlying strength. I road cf bikes exclusively the last couple years and they took 100 times the abuse any of my chairs ever will with no failures whatsoever. Loading and unloading a chair isn't the same as pitching a bike down a rock chute as far as impact and abrasion. Any crash that destroys a well built cf frame would have destroyed an aluminum frame faster.

    If you want to see some clear measured and documented demonstrations of the superior strength and toughness of a cf frame read this article and watch the first video to the end where they smash a cf frame into a concrete block without any damage.
    http://www.pinkbike.com/news/santa-c...-test-lab.html

    Bike riders are lucky that they get to have all of that cool carbon stuff. Such are the luxuries of using mass production! Carbon stuff keeps getting better and better, but very little of it is custom one-off work. Of course, there are some independent carbon frame builders, but most of them use tubes and lugs. Not too many out there doing custom mold work for one or two frames. The setup necessary for making ONE SIZE of ONE MODEL for ONE MANUFACTURER (of bikes) probably costs $20,000 in tooling. It'll be tough to effectively incorporate that technology into everyday chairs. Even the one-size-fits-all carbon handcycles cost over $10K. It would be tough to make all-carbon everyday chairs in just a S, M, and L.

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