carbon fiber handlebars - Page 2

Hmm...

Overthinking? I just told you what I did with my bike... If its overthinking, than I'd rather spend those few extra seconds thinking, then a few weeks in hospital...

Myth of Carbon Fibre? There aren't any...

I'm not sure what the argument here is about. I never thought it was in dispute that carbon components and tubes failed in a different fashion than steel or aluminum ones, and that it was important to keep an eye out for cracks or fissures.

At the same time, feanor isn't insisting that carbon fiber is a disaster prone material. He said he rides a carbon frame.

Don't let damage go unchecked, and you'll be fine with carbon stuff. We're in agreement here, aren't we?

Yeah,I forgot I see folks lying about bleeding to death from flying shards of catastrophically failed CF all the time. Try and tell me an ultralight aluminum bar won't fail just as fast and with no warning.

PULEEZE!

I really have to comment about the failure properties in CF.
It IS a myth that carbon breaks suddenly and violent. In fact is has a more gentle and warning way to break.
I found out last month, that my Cinelli RAM bars had been broken on the flat part on top, both sides, for a couple of months. (Probably due to a bad crash). It had two vissible cracks, that went from the middle to the bends. I only discovered it, because it felt a little soft when sprinting...
This shows how much strength carbon has, even if the integrety is gone.
In a very thorough test done by the german "Tour" magazine, tests showed, that carbon forks after a dynamic load test, to the point, where a visible crack appeared, it still had very high strength reserves when applied to a static load test.

The CF mythology mongers would probably loose sleep over that one. Not me tho.

For myself, I wouldn't "lose" sleep over that particular one either... Not enough force generated to do damage even if the bars were made of balsa wood.

Boudreaux,

No offense, but you have yet to offer a serious rebuttal against any of the points raised here to which you don't agree.

If I'm understanding you correctly, anyone who thinks that carbon fiber has the potential to fail catastrophically, or anyone so paranoid to bother to inspect a carbon fiber frame or handlebar set is simply and obviously beneath contempt, yes?

I'd be interested to know your expertise on this topic, if you have any expertise. Or at the minimum, I'd like to know the information that is animating your views.

My view on carbon fiber durability and resistance to failure is based mainly on what Craig Caffe has to say about it. Caffe, being one of the country's premier builders of carbon frames, is hardly a critic of carbon fiber. Nevertheless, he has made the point regularly that carbon fiber frames and other stressed components like handlebars can fail catastrophically as a result of impact damage.

I have no disagreement with you there Mario... But like real estate, it's all about location There are sections of the carbon tubing in a CF frame where the walls are very thin... So much so that clamping an area like the top tube in a shop stand with even moderate clamping force will crack it (this is not only from manufacturers warnings, but from a club mate who cracked the top tube of his Trek 5500 in exactly this way (Trek replaced it for him too!)

I saw the frame after it was broken... it didn't "peel" like delaminating CF sometimes does, but broke clean in a "jagged" circle all the way around.

Just out of curiosity (around 7 or 8 of us from the club came over to look) We "bent" the tube ends at the break clear of each other so that they didn't rest on each other and one of us sat on the saddle and gradually applied weight... the whole frame flexed at the junction of the down tube and the BB shell with only a little weight...

Our conclusion is that if the top tube broke in this same way while riding the whole frame would have collapsed by snapping at the BB... With the added thrill of perhaps getting skewered by a part of the frame...

Your experience with the Cinelli bars is different because the flat area at the top is probably reinforced, or at least much thicker since bars are meant to support load in that direction... Maybe if the crack was at the front of the bar and you pulled it straight back, the failure would be different...

But I am glad that your CF bars held out for you the way they did! Nasty business when you "drop" out of the drops You also mentioned the static load test of the cracked CF fork... Did they stress it to yield point? or just stop when they reached a respectable load number?

Have a good one!

Good discussion here. Certainly we all need to pay attention to cracks and damage in frames, forks and handlebars. But I wouldn't think the type of failure that occurred on the 5500 would be a hazard while riding. After all, that failure was due to the compression loads of the workstand clamp, not any loads which would occur on the road.

I think most cases of CF failure on bikes ought to be similar to the Cinelli bar case: the epoxy laminate layer will crack and things will get creaky/flexy long before the CF separates. As opposed to aircraft structures, we have the big advantage on the bike of being able to hear, feel and see things going bad as they happen.....and we can readily stop to check it out.

Dan

DHK,

Granted, the failure was caused by stresses you would never encounter on the road...

Potential hazards would be something like, during a shift while climbing, dumping the chain off the small ring and ending up planted straddling the top tube... That kind of loading could cause a problem with the top tube and a crack on the bottom of it could develop into something worse in a subsequent crash, rough road, etc...

The thing that really had me going about the 5500 frame was it broke kind of like an "eggshell" just cracking clean along a fissure (I suspect it was due to the very thin walls in that area of the tube)... I was expecting to see a delaminated fibrous "crushed" area, not that kind of break... It made me consider the possibility that if you whacked the tube sharply with a hammer, it would just break away clean and not just "crunch"

Kind of reminded me of those stiff taffy candies that if you bend them slowly they would just bend, but if you bent them quickly, they would break clean...

At any rate, thanks for the comments! I think that CF is a great material all around for frames, and have no problems going over the whole bike for a few minutes before a long ride... Unlike Boudreaux who appears to believe that looking over your bike for 2 minutes before a ride is overthinking things...

Have a good one!

Your generalization bursh is too wide. Certainly it makes sense to check ANY peice of equipment regardless of material.

Interesting Question & Reply - CARBON

Easton EC90 Carbon Handlebar

HEY UNC: Has anyone at RBR had experience with the Easton EC90 195-gram carbon road bar? I'm thinking of buying one and any feedback is appreciated. Thanx! -- Tom C.

UNCLE AL FIRES BACK: I've got a buddy who has used this bar since it first became available. He loves it for its light weight, shock-absorbing qualities, nice bend and super strength. In fact, he loves it so much that he bought a second one for his backup bike, which is a Merlin.

Can you imagine having a Merlin as a backup bike? I'd like to imagine having a Merlin at all. His primary bike is an all-carbon Calfee.

My friend believes that carbon eventually turns into diamonds. I believe he's nuts, but we gotta love the guy, anyway. We call him "Carbon Man."

The red EC90 bar is a work of art. It's incredible to hold in your hands. I've never seen anything quite like it. It's a shame to cover it with bar tape.

FROM WILL V.: I've had an EC90 on my Trek 5500 for almost a year. It's super light, super stiff, excellent for damping road shock, and all-day comfortable. I've used it for racing as well as extended climbing in the Alps. The EC90 is a steal at $160 when you compare it to the European carbon bars. The Deda Spectrum and TTT More are listed at $350, and the Cinelli Ram is a whopping $470!

FROM RICK T.: Uncle Al, I'm surprised at your review of the Easton EC90 carbon bar. You neglected to mention the most important "feature" -- it snaps like a twig if you go down in a crash. I've seen three of them do it at races this year.

UNCLE AL FIRES BACK: So do collarbones, Rick. There are trade-offs whenever we push the technology edges. I don't think I could pedal a bike that was built to be crashproof, because it would certainly be heavy.

You might only bend an alloy handlebar in a crash, but you wouldn't still use it, would you? You should never try to bend back a bent bar. It would be a time bomb waiting to go off.

WARNING FROM EASTON: Do not use clip-on aero bars on Easton's carbon road bar -- or on any lightweight road bar in aluminum or carbon, for that matter. The clamp design on aero bars is generally of poor design. Most of these clamps are not round and therefore force the bar into an oval shape when torqued to the proper values. This is not good for a handlebar and can lead to breakage. If you want to use aero bars, you need a heavier handlebar closer to 300 grams.


Artcile from: www.roadbikerider.com

And how often do you unwrap your bars to check and see if a stone might have damage them? After every ride? How about 'stress risers' from where the brake levers calmp them?