GoldenMotor.com Forum
General Category => General Discussions => Topic started by: anne@yourkitchen.com on May 24, 2014, 06:23:46 PM
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Hi, brand new here but keen.
I have a XTC full composite Giant.
Anyone done one yet ?
I like the idea of Smart Pie, but don't want to ruin a very nice bike, prob sell it if I cant.
Must have Magicpie ;D
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Hi Again
Any info on installing onto composite frame will be brill
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Hi and(https://i.imgur.com/evDSMvT.png)to the forum.
Is this the bike you're talking about?
(http://4.bp.blogspot.com/_V54WWNeyyp4/SrJp549cnXI/AAAAAAAABps/mVNR_0PHabY/s1600/DSC00268.JPG)
I really don't think carbon fibre and high axle torque will be a good combination.
It might just be feasible with a front mounted Smart Pie and some custom made torque arms, but I certainly wouldn't risk fitting a rear mounted Magic Pie into a composite frame that isn't designed to withstand any torsional load applied directly to the dropouts.
I'll make my prediction now:
Magic Pie 3 - Composite Frame Nil
(and perhaps some extra time for injuries too)
:o
Alan
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Mmmmm that don't look good, what happened ?
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Unfortunately, I've no idea what caused the damage in the photo, I just came across it on bustedcarbon.com (http://www.bustedcarbon.com/) during a Google search.
It would seem that carbon fibre frames often suffer from self-harming when they are feeling really stressed, driving into a garage with the bike still mounted on the roof rack can instantly increase the stress level of both the bike and the owner. ::)
Alan
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Carbon fiber has a different failure modes than steel or Al. But they both can fail. I've built and broken stuff made of both......
Carbon fiber can resist tremendous loads, but it doesn't bend or neck down like metal when loaded to failure. It fails dramatically, typically by shattering. Imagine if the bike frame was made of steel, and large angle bends were in the spots where the CF is split. Would it be any less useless than the three pieces in the photo? Maybe it doesn't look as dramatic, but in my mind, broke is broke.
The nice thing about CF is that you can quickly increase the load capacity of a component by simply increasing the thickness of the existing CF section. Think about how hard it would be to increase the wall thickness of a 1" diameter, 2 foot long steel tube by .010" . With CF, you need only abrade the existing tube to ensure adhesion, and then wrap it with 1-2 layers of 3K CF fabric. Need even more strength? Wrap it with 6K, 12K, you get the idea.
If the frame you are talking about has Al. dropouts, that would be the more probable failure point. The torque would likely open up the slot.....
CF is some tough stuff. But people can break anything.......
TTFN,
Dennis
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Imagine if the bike frame was made of steel, and large angle bends were in the spots where the CF is split. Would it be any less useless than the three pieces in the photo? Maybe it doesn't look as dramatic, but in my mind, broke is broke.
Dennis, it would be easier for one of your cycling mates to carrying the broken remains home it they were still held together in one piece, and no chance of any carbon splinters being embedded in their shoulder either:
(http://1.bp.blogspot.com/_V54WWNeyyp4/SsEtlo8XXlI/AAAAAAAABsM/tSLkeVeGYcw/s1600/627050942_RWKJ4-L.jpg)
But, on second thoughts, the separate parts of the carbon frame should also be able to fit inside the ambulance along with the rider. ???
Alan
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Hi Alan,
Your concern about CF splinters is understated. The ends of breaks are incredibly sharp and jagged. If you happen to neglect tucking in a single tow when laying it up, once the epoxy cures it becomes a very stealthy knife, capable of causing great harm and quite a bit of swearing......
But damn, is it light....
TTFN,
Dennis