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Are Carbon bars ok?


crazyt

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Interesting readĀ on the subject.

https://mbaction.com/the-carbon-conundrum/

Seth, you should definitely ride an aluminum bar if it makes you feel like you can shred harder. If your AL bar fails on you, you should definitely move to a Ti handlebar. Then if your Ti bar fails, then you should definitely move on to a solid section of cold forged steel rebar. šŸ˜„

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21 minutes ago, Teamsloan said:

Interesting readĀ on the subject.

https://mbaction.com/the-carbon-conundrum/

Seth, you should definitely ride an aluminum bar if it makes you feel like you can shred harder. If your AL bar fails on you, you should definitely move to a Ti handlebar. Then if your Ti bar fails, then you should definitely move on to a solid section of cold forged steel rebar. šŸ˜„

Good read. Glad I'm replacing my Renthal Bar with a new one. My other two bikes both have Answer Protaper carbon bars, which seem to always be on sale for really cheap. Not sure if that is a bad thing or not. Looks like they fall under the same company that makes Manitou forks. I don't ride or crash those bikes nearly as much.Ā 

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2 hours ago, Teamsloan said:

Interesting readĀ on the subject.

https://mbaction.com/the-carbon-conundrum/

Seth, you should definitely ride an aluminum bar if it makes you feel like you can shred harder. If your AL bar fails on you, you should definitely move to a Ti handlebar. Then if your Ti bar fails, then you should definitely move on to a solid section of cold forged steel rebar. šŸ˜„

"We advise that any product, carbon or aluminum, be replaced in the event of an accident. Once you have come off the bike, itā€™s hard to tell what forces may have gone through the handlebar as the bike cartwheeled down the trail. Particularly with carbon fiber, it may not be evident that there is structural damage. With aluminum, a bent handlebar is clear evidence that the structure has been compromised. Carbon fiber is much less ductile, and although the bar may look fine, the next big impact, like a heavy landing, may break the bar if the strength has been compromised in a previous impact. This could result in injury, hence our advice to change the bar following an accident. "

'nuff sed.

I much prefer my handlebars to show "clear evidence that the structure has been compromised"

over

"although the bar may look fine, the next big impact, like a heavy landing, may break the bar"

It's not so much that they will break with no clear evidence, it is also about how they will break at the worse possible moment.

No siree, that ain't for me.

Ā 

Edited by Ridenfool
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I think this is also an interesting takeaway from the article...

"Are carbon parts more susceptible to failure than alloy ones if they suffer damage?

Renthal:Ā Yes and no. Yes, as carbon is obviously a softer material than aluminum, so damage can occur due to direct contact with rocks or the ground more easily. No, as aluminum has a grain structure that can propagate cracks if surface damage occurs. Carbon fiber doesnā€™t exhibit this type of crack propagation. We fatigue-tested aluminum and carbon bars with very similar surface damage. The fatigue life of the aluminum handlebar was reduced due to surface damage, but the carbon bar was not affected. That said, we still recommend replacing any carbon or aluminum product that has been damaged."

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They didn't really answer the question, beyond the "Yes and No" response.

It sounds as if they picked a particularly vague type of damage (surface damage), for a test where they knew the carbon would be more resilient. I'd be more interested to see a breaking strength (not bending strength) of both bars with controls clamped on them.

What percentage of carbon bar failure is the result of surface damage from contact with rocks or the ground? Seems like most of the photos I've seen are breaks at clamping force points.

Ditto with aluminum bar failure from surface damage? Most damaged aluminum bars are bent, not broken off.

"The fatigue life of the aluminum bar was reduced ..." means they tested it using a method and applying a force in a way the carbon will perform well under and aluminum will not. So what? Were the levels of fatigue induced into the bars similar to normal use, or, was the force selected specifically because it would paint a rosy picture for carbon and was actually well beyond an aluminum bar's expected operational range?

Then, the patent disclaimer at the end to buy more aluminum or carbon bars every time you fall down.

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I've been running carbon barsĀ for 11 years across multiple bikes, hadĀ countless crashes, but never had one break (chips on the surface too).Ā I may replace them every 5-6 years, but this isn't unusual for other parts on my bikes. I never considered carbon bars having a bling factor, only lightweight and functional.

It mentions in the article that both barsĀ areĀ designedĀ with similar ultimate strengths (I think you used the term breaking strength), but each material has different failure modes. Clamps can deform the outer diameter of the carbon bar when overtightened and can cause the weakest area for failure. Once aluminum alloy goes through it's stress/strain proportional limit (rebounds back without deformation), it then goes through its yield strength (bending), strain hardens, and then fatigues out and breaks. The carbon fiber yield strength is so close to it's ultimate strength, the impression is that aĀ failure happens unexpectedly and at a much lower ultimate stress than aluminum. We could go into lattice slip planes of Al, dislocations, propagation, inclusions, but that gets boring..

I think we're all set in our own beliefs and experiences. Ride aluminum. Ride Carbon.

Signed, Chuck Yeager- a weight weenie, pro wannabe, weekend warrior

Ā 

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  • 1 month later...

Prime example here of carbon bars ready to shit the bed. Look to be in good shape at first glance and then I put my glasses on. They have been over clamped at both ends and at the stem. The cloudy spots look to be some separation going on. Put these on your bike and you'll have Weyless teeth.

iffy bars 010.jpg

iffy bars 012.jpg

iffy bars 003.jpg

iffy bars 002.jpg

iffy bars 001.jpg

iffy bars 013.jpg

iffy bars 014.jpg

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12 hours ago, JRA said:

Prime example here of carbon bars ready to shit the bed. Look to be in good shape at first glance and then I put my glasses on. They have been over clamped at both ends and at the stem. The cloudy spots look to be some separation going on. Put these on your bike and you'll have Weyless teeth.

iffy bars 010.jpg

iffy bars 012.jpg

iffy bars 003.jpg

iffy bars 002.jpg

iffy bars 001.jpg

iffy bars 013.jpg

iffy bars 014.jpg

and the only reason why there is anything wrong with those bars is because they are carbon. if they were aluminum, they would be in 100% great shape in the condition those bars are in. Ā so literally - what is the problem here? real answer: becauseĀ carbonĀ 

Edited by Seths Pool
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