I have always wondered about these bars, I am glad that I got some legit information regarding how faulty they are.

Sorry about them sucking for u though.

Like I said a couple of posts back, I have two of these handlebars and they've been fabulous.

I doubt the bars were the problem. Just blind over tightening; relying on a torque wrench rather than good wrenching technique. Bars joints should be tightened just enough to keep them from slipping. Especially when you are tightening a relatively stiff clamp to a relatively flexible bar.

It's easy to get a carbon fiber product to look good from the outside, but you never know about what's underneath. You might like your bars, but I'm telling you these are not well made and are not worth risking your life over. I've never seen anything like this. Even if the bars (or stem) was out of spec, it took almost no force to crush them. The underlying structure is weak regardless of how well made they look on the outside.

Doubt it all you want, but these were not "blindly over tightened." I would say they started crushing even before they would have been clamped down enough to prevent slipping. In other words, the bars failed before you or anyone else would have considered them tight enough through "proper wrenching technique."

I love how posting about a problem on the internet always results in at least one "find a real mechanic" type of response.

I'm in for having the face plate cock-eyed. The crease looks very similar to a set of carbon bars that I wrecked doing this.

It was a case of poor installation. You heard them start cracking and continued to tighten. The second there was any type of resistance that wasn't normal you should have backed off and checked the alignment. The fact the crack is only on one side of the bar indicates that either there was a poor mismatch of the bar/stem diameters or the faceplate wasn't aligned correctly.

Looks like your friend owes you some new bars.

Carbon paste can be applied to carbon bars at the faceplate, and can allow you to use less torque to hold the bars. Not much less, but a bit. Can also help with bars that slip as well, have used it on aero bars clamping to carbon base bars before and while not perfect, worked ok.

Jeebus haha. At least the outcome was nice!

To the prior Mikey post, my bars are alloy so the carbon aerobars are safe to clamp. Just saying in general, I like to torque everything to the number it says on the product after that experience. Very scary stuff when you're moving along at a high rate of speed. Luckily a failure of any sort didn't happen! :)

Thanks for playing, but no.

The crack being on one side of the bar means nothing. It means that is where the carbon fiber failed. Nothing more. There was no more resistance than any of the dozens and dozens of times I've installed handlebars. This isn't rocket science, you know. I didn't realize the cracking noise was the carbon bar itself. I wouldn't expect that when there was hardly any force being applied. Like I said before, the noise occurred long before I got anywhere near the 5 Nm mark. It was making noise practically from start to finish. Not sure what you mean about the faceplate not being aligned. I put the faceplate on, threaded the bolts by hand for 1-2 turns, then went in a cross pattern from there, making sure to tighten them as evenly as possible. Misalignment was not the case here.

So, in other words it couldn't possibly have been your fault...is that correct? At least that's how it sounds since every time someone offers a very reasonable/plausible cause you refute it.
Question, I take it the bar itself did not have a torque spec on it, correct? If not, why guess, especially since you had no idea and severely guessed wrong enough to crack the bar. It's OK to admit to your friend(s) that you're not a pro tour wrench and are not sure how to do something. Most guys would rather have you admit to not knowing or being sure then to have a busted part in their hands.
There are ways to get torque info on most parts with a bit of internet searching and maybe even a phone call to the company. It's usually not that hard to get the needed info.
Misalignment of the stem, continuing to install once you heard the "wrong" noise, not enough experience installing carbon components etc all played a part in the busted bars. And yes, perhaps the bars weren't perfectly round but that's rare but [I]could happen[I].
I ride a lot of carbon bike and components and when I'm not sure I make every effort to get the needed info before guessing in order to avoid exactly what happened to you and your bud.

You are correct. I did not make a mistake in installing these bars. I am no pro tour wrench, but I know how to install handlebars, carbon and aluminum alike. I've done it many many times before (with quality products) and have never run into this issue. I did not "guess" the recommended torque setting. If the bars are going to crack at 5 Nm (note: they cracked well before this point), they are ****ty bars. I did not refute the reasonable/plausible causes that were brought up. It's very possible the stem and/or bars are out of spec. The only thing I refuted was that I installed them incorrectly. I will continue to refute this because I am certain I didn't do anything wrong when installing the bars. Some of you are acting like you really need to wrench for a living to install carbon fiber handlebars without breaking them. LIke I said before, it's not rocket science.

Like someone else already said, what good would it have been if I did stop when I first heard it crack? They were already rendered broken and unsafe at that point.

*edit* I would have been a ****ty friend if I pretended like nothing happened and let him ride with damaged bars.

I find it entertaining, the number of internet doctors/mechanics that are certain the failure was due to the installer. Granted, I might have stopped when the cracking sound first occurred, but if it was so early in the installation process, the bars were toast from the beginning, and possibly came that way.

Thank you.

Also, I did stop when I first heard the creaking/cracking noise, but everything checked out okay at that point. There was no visible damage to the bars at that point. All three people in the room heard it, but since there was nothing visibly wrong we thought it was the face plate bolts creaking as they turned. Now, I've never heard face plate bolts creak while turning, but at the time it seemed like the only explanation for the noises.

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Stick with aluminum bars would be my advise.

Lesson learned and I am going to stick with aluminum bars and stem. I'll just order 3T Ergonova's, the same on my Cervelo. I might just get a 3T stem as well to prevent any issues if it was a ****ty stem.

Btw, I don't have any doubt in ilovecycling's wrenching skills. He even mentioned to me that the bars seemed too light for the price and recommended I just stick with alum.

This is what I heard too. Thats why you don't torque numbers on bars and seatposts.

Maybe that bar was doomed the day it left the factory.

Also the "out of round" face plates that Dopolina mentioned happened to me with a 3T Arx stem. Top of the face plate was biting down on my EC90 bars...left some nice marks.

Hum, that sounds very low. Zipp for example has a max torque spec of 8nm

http://zipp.com/bars/slc2-bar/#

Aluminum corrodes. I've had al bars that wer just about ready to snap from the salt air, and sweat on the trainer.

Nothing is immune to failure.

I find this post hilarious. Basically you're accusing him of being uninformed yet everything you've posted he's already answered. Most importantly, the part about the cracking sound starting BEFORE the bars were at the torque that would prevent them from slipping. So regardless of what the torque rating for the bar was, he hadn't reached it yet. Also, who cares if he keeps going after hearing the initial cracking sound? Once the sound is heard, the parts are toast either way.

It's OK to admit to your friend(s) that you're not a reading comprehension pro and are not sure how to interpret text on a screen.

Yeah I saw that the other day... someone on here has the boomerang style wing handlebar... 8Nm seems Very high considering many stems don't even go that high. I wonder if there is an aluminum ring in there for support... or if it is just Very thick carbon at the stem clamp/aerobar clamp section...

as for low, I torque to 4Nm and have NEVER had bars slip, but they typically have a rough finish around the clamping section... I assume that helps.

i think the reason many of us doubt the ability of the helping friend is because he continued to keep wrenching after hearing cracking sounds.

would stopping after cracking fix any issue with the bars? no.

would continuing to wrench after hearing cracking in carbon bars fix anything? no.

it is irrational and counterproductive to continue the process once failure has occurred.

also, i found it weird that the friends mentions thinking that the cracking might have been the sound of the bolts threading in.

if the integrity of the bars was compromised, but was not visible from the surface, then the safety of the rider would be at risk.

if i worked on someone's bike and heard cracking or any other breaking noise, i would inform the person that the bike may not be suitable to ride.

so while we do not have proof that the failure was due to the mechanic or the handlebars, there are many of us who would refuse the service of the man who keeps cranking after hearing cracking.

ps- in addition, that the mechanic will not admit that it was foolish or an "dumb moment" to continue wrenching after hearing cracking, adds to the doubt of his claims.

I know Easton reinforces the clamping area on their carbon bars. IIRC, my Deda stem specs 8nm...but I always stop at 5.

That Cutter bar looks to be clear coated...possible its the clear that cracked and not the carbon?