Has anyone broke a set of carbon bars……………….

Carbon weave? Bah Race Face has been doing that for years.

http://www.raceface.com/components/handlebars/57/

“Why are people using XC carbon bars and landing from jumps? duh!”

So there can be no jumping in XC then?

Motocross bikes seem to always have alloy bars on and they take some proper hammer. Quite thick they are though. I have slightly bent a few though when I used to fall off. Carbon is purely about weight. Nothing to do with how strong they are. if they were actually stronger would top end MX bikes not have thick carbon bars etc? The lads who do MX are bigger tarts than anyone on here too, so looks would come into if it was an equal strength thing.

I suppose the manufactures of carbon bars do test them well. But sticking them on a machine and wating for them to snapis like anything not a real world test. The machines dont have ham fists that slightly over tighten bolts on stems and I suppose they dont chuck the bars on the floor under a riders arse.

“brand new whyte hardtail so fatigue is unlikely to have been a factor but an akward landing may have”

That looks more like the shifter or brake lever were overtightened somewhat
Don’t carbon (or otherwise) bars usually go next to the stem?

I’ve used a pair of Easton cnt bars many times at Coed y brenin and other trail centres around wales for well over a year,When I started using them I was 186lbs,down to 175lbs now and Ive never had a problem with them.

And I haven’t been shy when it comes to giving them abuse.My riding buddy on the other hand wont touch them,He spends his nights worrying about when the carbon rear on his 575 will snap!

Again I say CNT versus carbon weave.

That looks more like the shifter or brake lever were overtightened somewhat
Don’t carbon (or otherwise) bars usually go next to the stem?

This is what worries me about them. I cannot trust my sausage fingers not to overtighten things, and it seems that torque wrenches aren’t effective on carbon (does it compress slightly under tension?)

“does it compress slightly under tension?)”

What is ‘it’

I think you’ve got something mixed up there

I cannot trust my sausage fingers not to overtighten things

I often use the long end of the alley key inserted into the bolt I’m snugging up when doing up stem faceplates and controls on carbon bars. If you’ve only got the short bit in your fingers, you physically can’t over torque it becuase you’ve got no leverage. You’re only doing stuff up enough to stop them moving anyway.

Apart from seatposts 🙁 Even using proper carbon assembly paste, you seem to have to crank them up more than I’d like to stop them slipping.

It’s not the carbon per-say, it’s the way the levers and shifters are fitted on that causes problems. If they are overtightend (which is easy to do) it can pinch the carbon and weaken it. One of my mates had this very thing occur and he only discovered the fault when the bar snapped at 30mph on a very rocky path. He spent a number of weeks going back and forth to hospital, spent his 39th birthday being operated on and now has pins holding his arm onto his shoulder. Since then we have all swapped our carbon for aluminum. A decent aluminum bar is not that much heavier than carbon and will be considerable more reliable. I no longer have that niggerling feeling that the front end is going to give out each time I lauch off a jump or plummet down a bridal path.
Good luck with whatever you choose.

“does it compress slightly under tension?)”
What is ‘it’
I think you’ve got something mixed up there

Yes, probably! 😆

By ‘it’ I meant the carbon bars.

Probably I’m just confused/wrong. In my imagination, if the carbon compressed more when clamped than alu did, the carbon might get significantly deformed (to the point of getting damaged) even when only being torqued to what on alu would be a low figure.

So, here’s a thing. All you guys who’ve broken carbon bars, and replaced them with Ali ones, what’ll you do if you break the ali one?

75kgs. Never broken a bar in my life; carbon or ali.

Carbon bar failure is often attributed to sharp edges at the stem/bar interface combined with overtightening effectively acts like a knife cutting into the bar. Raceface’s Deus stem has rounded edges on the stem clamp area to prevent this.
Over tightened brakes/shifters will do much the same thing.
I run shifters and brakes less that tight on all my bikes.. if I crash, my shifters and brakes can rotate which should protect the levers from bending/breaking.
Repeated twisting of shifters/brakes can leave score lines around the bar which is another problem.. but this also affects alloy bars too.

I trust all my carbon bars implicitly

i bought a 2nd hand set of ea70s from here, abused them for 2 yrs on 1 bike, then 2yrs on another bike. over that time they suffered quite a few scratches and falls with no problem. eventually i just got wary of the damage to them and bought a replacement set. i then decided to smash the bars as i obviously didn’t want to sell them on, or have anyone else find them and use them or sell them… you wouldn’t believe the amount of force i had to use with a lump hammer, and even when they were properly smashed they still had strength to them.
i can’t imagine the sort of jra incident that might “snap” a set of properly installed carbon bars.

we should donate all our old bars that we have lost faith in to STW and get them to video some destructive testing to see how much each material can take, would be very interesting.

A mate snapped a set in anger – he got p***ed off on a ride and chucked his bike to the side of the trail. The bars broke. Hard to imagine how much angrier he could get after that – turning green maybe?

clubber – Member

i’d rather have something bend than snap. hence metal not carbon

I snapped a Ti bar. I’ve seen several snapped alumninium bars. Your point, please…

Trek carbon warning

paragraph 2. that’s all, really.

Carbon has proven its performance pedigree. However, carbon fi ber has unique qualities. Unlike metal parts,
carbon fi ber parts that have been damaged usually do not bend, bulge or deform; they break. A damaged
carbon part may appear normal at a quick glance, but could suddenly fail without warning. Carbon forks,
handlebars and stems are most critical.

From the trek website. The reason why I will never use carbon components. I have never seen a broken metal component that has not had obvious signs of existing cracking. carbon is stronger for the same weight for sure – but its the catastrophic failure mode that scares me.

Unfortunately, in my experience, metal parts don’t bend bulge or deform either – they break. Or they bend so far that you still crash or worse still then bend a long way then snap and leave a razor sharp edge for you… (seen all the above in my time riding).

In fact, I think every statement made in Trek’s quote above could be applied to metal parts in the real world (or at least non-DH weigh a ton versions)

I’ll stick with carbon, thanks.

Back in my canoe slalom days I used carbon paddles – when using sweep strokes in to or out of eddy we frequently bent to paddle shaft to 20 -30 degrees (often moved hands down the shaft to get more leverage) never had as much as a crack in them – and they are a lot less robust then handle bars

Any hoo when jumping don’t you land on the back wheel thus not weighting the bars

they are a lot less robust then handle bars

obviously not…

One of the likely ways for aluminium to fail is by fatigue, leading to fast fracture.

Requires a crack to be present, and stress intensity at crack tip can lead to fast fracture, despite nominal stress levels in overall section being below yield strength of the material. Crack may not be visible to the naked eye.

So metallic bars may just break when jra.

That’s why I like Easton EA70 bars , they’ve been shot-peened (as others have been also), which helps to alleviate crack initiation on the surface.

But i also have Easton EC90 monkeylite bars.

TandemJeremy – Member

Carbon has proven its performance pedigree. However, carbon fi ber has unique qualities. Unlike metal parts,
carbon fi ber parts that have been damaged usually do not bend, bulge or deform; they break. A damaged
carbon part may appear normal at a quick glance, but could suddenly fail without warning. Carbon forks,
handlebars and stems are most critical.

From the trek website. The reason why I will never use carbon components. I have never seen a broken metal component that has not had obvious signs of existing cracking. carbon is stronger for the same weight for sure – but its the catastrophic failure mode that scares me.

Over the years I’ve had aluminium bars, cranks, a seatpost and a stem snap without any obvious signs of them about to break!

In defence of carbon, a few years back I bought some Easton EC 90 SL forks for my road bike. Whilst I had every faith in a set of 350 gram forks being plenty strong enough, there was always a question at the back of my mind about how strong they really were.
A mate of mine who owned a set of the same forks had a car pull out on him whilst he was doing about 30mph, he scrubbed a tiny bit of speed off before colliding with the car and ended up hitting the front wing and sailing over the bonnet. Amazingly, although written off, the forks stayed in one piece, the only damage being a crack running from the underside of the fork and through the hole where the brake mounts.
This put any doubts that I had to the strength of the forks out of my mind.

two hats – the signs would be there – a crack propagating. Metal components simply will not snap JRA – there must be a fatigue fracture starting first

As I said, there were no signs.

TJ – a couple of points here.

First, most people don’t check the metal components before each ride and even then could easily miss cracks

Second, it’s perfectly possible to have a small crack in metal that can’t be seen (easily) which can then rapidly lead to breakage.

Just because it’s there and you can see it after the crash doesn’t mean anything, does it?

it means that there were warning signs that you missed.

Its two different failure modes – gradual or catastrophic. I know which I prefer. The fact some folk dont see the warning signs of a gradual failure is neither here or there – I am confident I would.

For the same weight carbon is stronger, for the same strength carbon is lighter. Its only marginal however and I cannot trust anything that when overstressed will turn to dust. I like stuff that bends

My choice

Looks like bars are good but just don’t over tighten the stem and add ons like brakes and shifters.

Use a decent torque wrench?

Haven’t snapped mine yet and I weigh 200 lbs.

@james I can understand the odd landing in xc but some of the people have busted bars doing silly jumps that you wouldn’t see in xc series.

LOL – Out of interest, do you check all of your bike EVERY ride TJ?

And even if YOU do (hell you’re so an@l, it wouldn’t surprise me), the vast majority of people don’t.

Plus, as above, you can miss a small crack very easily, particularly if your bike’s not spotless (do you also clean your bike to spotless every ride?) even if you do check. Yes, it’s a failure to spot but equally cracks can be near impossible to see if they’re small and neat enough.

I’ll stick with my point. In the real world, there’s actually no real difference in the end result of a metal or carbon failure…

Like comparing an orange apple and an orange similar but different

Three mountain bikes, three sets of carbon bars, two of which are six years old. One pair are on my SS, so get heaved on quite a bit climbing hills. Two of those bars are standard size, the oldest ones, and I have every confidence in them. I wouldn’t trust an alloy bar that old, especially a light one, and if one of those carbon bars fails, I will replace with carbon without a seconds hesitation, although I may go O/S when/if replacing. Certainly carbon bars make the ride more comfortable, due to their damping qualities, and for that reason I will stick with them. Had enough numb hands with alloy bars, thank you.

[Quote]Its two different failure modes – gradual or catastrophic. I know which I prefer. The fact some folk dont see the warning signs of a gradual failure is neither here or there – I am confident I would. [/quote]

You could put the whole non-destructive test (NDT) industry out of business.

For example: aircraft are now designed to damage tolerant, which means the tolerable defect size still be detected with a high degree of reliability. For cost effective purposes at inspection, this is generally visual cracks, but some components may require NDT inspection, where the tolerable defect size is below the visual inspection limit e.g. ultrasound, eddy current methods etc..

So depends how well those bars are designed and how damage tolerant they are, if at all. And if the crack in bars is hidden by stem?….clamping/unclamping stem lots could cause a defect to start in bar.

I think KennyNI and I may well work in the same industry and possibly do similar jobs, because he’s saying a lot of things that spring instantly to my mind as well as being very correct indeed!

I think one thing to bear in mind is that a component is not just its material, it’s what you do with that material that really counts. If a company designs a bar with the right level of overstress capability, chooses the right layup and gets it made by someone competent then a thousand to one it won’t break. If they design the bar so that normal stresses push it right to the limit, choose a crappy layup (unidirectional bars, anyone?) and get it made by numpties, it’s going to ruin someone’s day.

So there’s no ‘carbon bars break’ or ‘aluminium bars don’t’. Rubbish carbon bars will vapourise. Good ones will go and go. Same with any material. Buy what suits your needs, but personally I’d be wary of super-mega-light-as-a-feather carbon stuff.

Jon

saladoger broke his Easton carbon bars this morning, they broke in exactly the same place as the ones in the pic above, right on the brake lever clamp.

I was there… and all he did was start riding and it just pulled off in his hand!

“if they were actually stronger would top end MX bikes not have thick carbon bars etc?”

MX bars aren’t built to stop them getting damaged when they’re ridden- they’re build to stop them getting bent like a pretzel/broken when 120kg of bike hits the ground at 30mph directly on the bars. It’s not a very good comparison.

from my own exp and of people i’ve been riding with who’ve ‘snapped’ bars in front of me, alu bars break from fatigue and are usually 2 yrs + old when they go and carbon bars have been crash damaged or clamps have been overtightened, lock-on grips have broken one of my carbon bars too.
cr-mo bars don’t break but are heavy.

a well clamped and non-accident damaged carbon bar, evenly loaded (2 hands on at landing) will stand far more than any of us can do on a bike, but carbon is really easily damaged by fitting errors, stem compatibility etc. I’d bet that every broken carbon bar here has been crashed grip-digging-into-dirt style or had a clamp-crush, it doesn’t always take a major off or gorrila-torqued bolts to overload one side and cause unseen damage. it’s unreal some of the damage we see on carbon parts, as if people think it’s harder than metal so do clamp bolts up to 500% of the torque settings..