# Why to MTB pros use carbon handlebars but not road pros



## Quinner (Aug 29, 2011)

Look at any road UCI event and you will see mostly cheap alloy handlebars, the reason cited is that they will survive a crash and allow you to continue to race without waiting for the team car (and perhaps prevent catastrophic failure), I guess there is tradition to consider too. So why don't MTB pros follow the same thought process? Are roadies just misguided?


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## Circlip (Mar 29, 2004)

Quinner said:


> Look at any road UCI event and you will see mostly cheap alloy handlebars, the reason cited is that they will survive a crash and allow you to continue to race without waiting for the team car (and perhaps prevent catastrophic failure), I guess there is tradition to consider too. So why don't MTB pros follow the same thought process? Are roadies just misguided?


Many pro road races are stage races. Getting dropped by the peloton early in a stage from a mechanical means you may miss the time cut for the stage, which means you are out of the event and all subsequent stages. That's a real PITA for a pro road team to be missing key helpers on the team roster that are supposed be be helping a team leader who often makes millions of dollars per year conserve energy.

In most MTB races, if you break something you can't fix you just call it a day, although in UCI World Cup MTB XC events and some other races they now have "tech zones" where you can get equipment repairs and replacements. The course loops for World Cup XC are relatively short and running with your bike to a tech zone often might not be that far away. Whether it's worth it as a pro to blow away a few minutes to get fixed up and then hop back on for a backmarker finish position is another question altogether. Pros have different considerations that mere mortals on this point. Based on many years of reading pro race reports around the world, I'm not recalling broken carbon bars as being a common issue anyhow.


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## Harold (Dec 23, 2003)

I would guess that part of the reason might be that it's too easy for a road race bike to be UNDER the minimum weight limit set by the UCI, so they selectively use heavier bits to ensure they meet that minimum.


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## Silentfoe (May 9, 2008)

NateHawk said:


> I would guess that part of the reason might be that it's too easy for a road race bike to be UNDER the minimum weight limit set by the UCI, so they selectively use heavier bits to ensure they meet that minimum.


/\ This


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## Spinning Lizard (Nov 27, 2009)

NateHawk said:


> I would guess that part of the reason might be that it's too easy for a road race bike to be UNDER the minimum weight limit set by the UCI, so they selectively use heavier bits to ensure they meet that minimum.


This and a lot of the pros do not like the carbon bars because they believe they are too flexy during sprints.


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## Mr.Magura (Aug 11, 2010)

Hey, it's obvious!

They can't afford carbon bars 


Magura


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## Quinner (Aug 29, 2011)

Not convinced by the weight theory, and sprinters can be treated as a special case. 

Whats more I don't understand why a MTB racer would risk dropping out due to a cracked bar anymore than a road racer would whether it be stage race or not. If nothing is broken on the bike you jump back on, simple. 

In 20 years of watching cycling I've never seen anyone drop out because of a cracked bar, however it's not confidence inspiring riding a carbon bar after having crashed and bars often take the brunt of a fall. Whether alloy is actually more likely to fair better after an impact with the road/rock is another debate.


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## heyyall (Nov 10, 2011)

Of course this is speculation unless you asked every pro why they set up his or her bike the way they want. Since we can't do that, here are a couple of interesting articles that gives a few insights:

Analysis: Eliminating the UCI bike weight limit is overdue

Note that this article points out the stock (high end) Madone is under the UCI limit so it has to get bulked up to meet the weight limits. Considering the frame is set, no changes are possible. Pros aren't going to go cheap on the gruppo, so that is going to be as light as possible. They aren't going to go with a grossly overweight wheel set. What's left? They could hang a steel water bottle cage on the frame and they can swap the bar. Since the bars are tapped and make for a poor place to hang a sponsor logo on, this is the only logical place to increase weight if the bike is under the limit and nobody will care or talk about it.

Here is the justification of Fabian Cancellara's build for the cobbles:
Pro Bike: Fabian Cancellara's Leopard Trek Team Issue Madone 6-Series SSL Paris-Roubaix | Cyclingnews.com

Given the amount of carbon already on the bike and the fact that if they crash, they generally swap bikes without hesitation, I don't think there is any concern regarding failed materials after crash. Best case is to replace.


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## LMN (Sep 8, 2007)

I have broken a carbon bar, but I have also broken two alloy bars, and I have been using carbon bars longer then I have been used alloy bars.

It would be interesting to see some data on actually sheer strength of a carbon vs. alloy bar. Is there any basis to common belief that carbon is weaker then alloy.


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## Harold (Dec 23, 2003)

Quinner said:


> Not convinced by the weight theory


It's not a theory. Have you weighed a high end road bike lately? Very easy to go under the UCI weight limit. There's a weigh-in for the bike prior to every race to make sure it at least meets the minimum. Too light, you don't race. I knew a shop owner in the early 2000's who had a project bike to beat the UCI weight limit. He did so...easily...and even strapped a bunch of electronics to the bike. That was 10yrs ago, and stuff is only lighter now by comparison.

Why are you not "convinced"?


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## ryguy135 (Sep 24, 2010)

My friend's Trek Madone with Shimano 105 with upgraded wheels comes in just a quarter pound over the limit. That limit needs to be killed. Along with most of the UCI's rules governing bicycle design.


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## ImaFred (May 16, 2009)

Weight is correct, that's why you see quite a few "heavier" saddles on pro bikes too... If you "have to" add weight might as well do it where you get comfort as a side benefit.


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## Shayne (Jan 14, 2004)

Quinner said:


> Not convinced by the weight theory, and sprinters can be treated as a special case.


Weights glued to a Cannondale in the 2003 TdF to make the bike legal to ride.

And I am by no means a sprinter and I flex the heck out of every carbon road bar I've ridden. It's unnerving.


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## Circlip (Mar 29, 2004)

ImaFred said:


> Weight is correct, that's why you see quite a few "heavier" saddles on pro bikes too... If you "have to" add weight might as well do it where you get comfort as a side benefit.


Post ^^^ wins.

On some pro bikes they literally add weights with no functional value to make sure they are over the minimum weight by at least a touch. They usually do this toward the bottom bracket to keep the handling positive with low center of gravity. If they are using any heavier components higher up, they must think it has some benefit. Saddles are an obvious are (saddle sores in a 3 week stage race don't sound very fun), or for the bars performance (stiffness for sprinters) and perceptions (maybe unfounded) of improved crash resistance versus carbon, given that many flyweight non-sprinting climbers use Aluminum bars too.


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## Quinner (Aug 29, 2011)

NateHawk said:


> It's not a theory. Have you weighed a high end road bike lately? Very easy to go under the UCI weight limit. There's a weigh-in for the bike prior to every race to make sure it at least meets the minimum. Too light, you don't race. I knew a shop owner in the early 2000's who had a project bike to beat the UCI weight limit. He did so...easily...and even strapped a bunch of electronics to the bike. That was 10yrs ago, and stuff is only lighter now by comparison.
> 
> Why are you not "convinced"?


Even my wife knows that road bikes can easily get under the UCI weight limit - off the shelf. I personally ride a road bike way under the limit, so you are way off the mark with your understanding of my response. I'm not convinced that weight is the real reason why road pros use alloy bars, although it may be welcome secondary consequence. If that were so why don't they use alloy pedals or seatposts as well rather than dropping weights down the seat tube? I think it's tradition and fear of breaking them/overtightening that is the principal reason, and for larger riders/sprinters it maybe flex.


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## Quinner (Aug 29, 2011)

Shayne said:


> Weights glued to a Cannondale in the 2003 TdF to make the bike legal to ride.
> 
> And I am by no means a sprinter and I flex the heck out of every carbon road bar I've ridden. It's unnerving.


Well done we all know that they add weights to road bikes, you miss the point.


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## heyyall (Nov 10, 2011)

Quinner said:


> Even my wife knows that road bikes can easily get under the UCI weight limit - off the shelf. I personally ride a road bike way under the limit, so you are way off the mark with your understanding of my response. I'm not convinced that weight is the real reason why road pros use alloy bars, although it may be welcome secondary consequence. If that were so why don't they use alloy pedals or seatposts as well rather than dropping weights down the seat tube? I think it's tradition and fear of breaking them/overtightening that is the principal reason, and for larger riders/sprinters it maybe flex.


re: bars -- You are right. We are sorry that we suggested otherwise.

re: pedals--that's easy. You have to spin them so weight really matters

re: seatposts--who knows, but dampening would be my guess.


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## shiggy (Dec 19, 1998)

NateHawk said:


> It's not a theory. Have you weighed a high end road bike lately? Very easy to go under the UCI weight limit. There's a weigh-in for the bike prior to every race to make sure it at least meets the minimum. Too light, you don't race. I knew a shop owner in the early 2000's who had a project bike to beat the UCI weight limit. He did so...easily...and even strapped a bunch of electronics to the bike. That was 10yrs ago, and stuff is only lighter now by comparison.
> 
> Why are you not "convinced"?


The bikes are light enough that the pros can run "heavy" power meter cranksets on their race bikes and still be under the minimum.


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## customfab (Jun 8, 2008)

NateHawk said:


> It's not a theory. Have you weighed a high end road bike lately? Very easy to go under the UCI weight limit. There's a weigh-in for the bike prior to every race to make sure it at least meets the minimum. Too light, you don't race. I knew a shop owner in the early 2000's who had a project bike to beat the UCI weight limit. He did so...easily...and even strapped a bunch of electronics to the bike. That was 10yrs ago, and stuff is only lighter now by comparison.
> 
> Why are you not "convinced"?


It's actually pretty rare for the UCI to actually put the bike on a scale. The only time I've ever seen it happen was for an uphill TT


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## peabody (Apr 15, 2005)

LMN said:


> I have broken a carbon bar, but I have also broken two alloy bars, and I have been using carbon bars longer then I have been used alloy bars.
> 
> It would be interesting to see some data on actually sheer strength of a carbon vs. alloy bar. Is there any basis to common belief that carbon is weaker then alloy.


it isn't weaker then alloy, the issue on the rd is in a crash generally the brifters twist on the bar, the clamp has a very high potential for scoring the bar, which is then carbons weak point.


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## LMN (Sep 8, 2007)

peabody said:


> it isn't weaker then alloy, the issue on the rd is in a crash generally the brifters twist on the bar, the clamp has a very high potential for scoring the bar, which is then carbons weak point.


I follow you. But I do wonder if in practice this the issue we believe it is (carbon is more vulnerable then alloy). I am not a material engineer, really all I know about the materials is "folklore".


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## DIRTJUNKIE (Oct 18, 2000)

So with all this talk recently of carbon bars being so fragile. I guess I should be concerned of my Easton Monkeylites. They have only survived some 2000 and some odd crashes with my 210lb heft over 12 years of use. I better head out to the garage and strip them off the bike because apparently they're not doing their job.


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## rockcrusher (Aug 28, 2003)

I think the issue with the road bars is that when hitting the ground they have a nice flat spot (the hooks) in which to sit while another mass lands on the other flat spot (the other hook) and they break. In mountain biking, if you land on the bar that way you will have a lot more problems than breaking a bar. An AL bar will bend with a racers weight on it and while it might not be perfect they can get back on and ride. A carbon bar or an aluminum bar might not get damage from hitting the ground as they will hit and turn the bar. If you land on it as I a said before you will be mightily hurting and be off to the hospital or more than likely.

Plus mountain bike racers rarely ride in large pelotons where someone might crash ahead and take down 20-30 people all landing on each others handlebars.


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## Quinner (Aug 29, 2011)

Theories on carbon is probably a mute point for many riders, they will probably go with a traditional tried and tested bar option i.e. an alloy one. Maybe because the consequences of bar failure would be pretty gruesome on a descent. Also think of Hancapie snapping his carbon steerer in (2008?) paris roubaix or Cancelarra breaking his carbon zipp 303 in 2010 paris roubaix (though he still won). I know its PR, but still...


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## ghettocruiser (Jun 21, 2008)

Quinner said:


> Also think of Hancapie snapping his carbon steerer in (2008?) paris roubaix


No help there. It was 2006, and that steerer was aluminum.


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## ImaFred (May 16, 2009)

That was such a bummer moment, felt bad for big George that was probably his most on form year at roubaix. After that Im almost sure he'll never win it.....matter of fact I believe he's going this year as helper to Thor


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## Caffeine Powered (Mar 31, 2005)

NateHawk said:


> I would guess that part of the reason might be that it's too easy for a road race bike to be UNDER the minimum weight limit set by the UCI, so they selectively use heavier bits to ensure they meet that minimum.


This. Quite a few brands have to add "ballast" because the frames and wheels are getting so light. And then there's the the rider's own input for the bars they prefer since the brands they're using run the full range of materials. Plus you can't win if you don't finish.


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## Berkeley Mike (Jan 13, 2004)

I like the flex.


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## ImaFred (May 16, 2009)

Berkeley Mike said:


> I like the flex.


I like a lil flex as well :thumbsup:


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## zebrahum (Jun 29, 2005)

LMN said:


> I follow you. But I do wonder if in practice this the issue we believe it is (carbon is more vulnerable then alloy). I am not a material engineer, really all I know about the materials is "folklore".


I work with carbon fiber every day and I can honestly say that if you are worried about carbon composites being strong enough then you really need to be worried about your metal as well.

You have to understand that carbon composites are far more sensitive to its construction (ply alignment, fiber orientation and type) than a metal would be, but that also means that it can be far stronger than a metal at any given weight (incidentally, that's also why I shudder to think about buying one of those really pretty looking knock off ebay carbon bikes. Who knows what design work went into those?).

Here's an example of some material properties:
"The stiffness of a material is measured by its modulus of elasticity. The modulus of carbon fiber is typically 20 msi (138 Gpa) and its ultimate tensile strength is typically 500 ksi (3.5 Gpa). High stiffness and strength carbon fiber materials are also available through specialized heat treatment processes with much higher values. Compare this with 2024-T3 Aluminum, which has a modulus of only 10 msi and ultimate tensile strength of 65 ksi, and 4130 Steel, which has a modulus of 30 msi and ultimate tensile strength of 125 ksi."
What is Carbon Fiber? Carbon Fiber Technology

So that's one example for one carbon composite construction (a plate). The strength of carbon in this example lies somewhere between Aluminium and steel. I'm sure with a bit of searching you could find particular examples using handlebars or seatposts and some real numbers rather than these base examples I found.

The drawback of carbon is "catastrophic failure" according to most. Well, I've only seen one carbon bike part fail and it was a Schwinn Homegrown that slowly broke straight in half before our eyes (completely awesome except it was the end of someone's bike). I've seen a handful of sheared aluminum handlebars broken from fatigue.

So you can have splintering failure from carbon or shearing failure from aluminum. Either way, I would suggest replacing your bars every 5 years or so just to be on the safe side. Stop being afraid of what things are made of and go ride your bike!


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## DIRTJUNKIE (Oct 18, 2000)

zebrahum said:


> I work with carbon fiber every day and I can honestly say that if you are worried about carbon composites being strong enough then you really need to be worried about your metal as well.
> 
> You have to understand that carbon composites are far more sensitive to its construction (ply alignment, fiber orientation and type) than a metal would be, but that also means that it can be far stronger than a metal at any given weight (incidentally, that's also why I shudder to think about buying one of those really pretty looking knock off ebay carbon bikes. Who knows what design work went into those?).
> 
> ...


Finally someone who knows what they are talking about on this subject.:thumbsup:


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## Quinner (Aug 29, 2011)

ghettocruiser said:


> No help there. It was 2006, and that steerer was aluminum.


doesn't really change my point does it?


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## jeffgothro (Mar 10, 2007)

IMHO screw all that crap, just keep a back up bike, c'mon, these sponsors got the moolah'lah's, I mean what the f**k...lol. (unless the sanctioning body dont allow it)?


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## twinkles (Oct 14, 2004)

Road bars are covered with tape, so a damaged cf bar cannot be seen and can fail catastrophically. A mountain bar is bare and can be seen if it's damaged.


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## torque29er (Oct 11, 2011)

Quinner said:


> doesn't really change my point does it?


Just for comfort...

Testing handlebars at Specialized - YouTube


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## Ciesiel (May 31, 2012)

*same braking point*



LMN said:


> I have broken a carbon bar, but I have also broken two alloy bars, and I have been using carbon bars longer then I have been used alloy bars.
> 
> It would be interesting to see some data on actually sheer strength of a carbon vs. alloy bar. Is there any basis to common belief that carbon is weaker then alloy.


many years ago I studied this subject and the braking point of both aluminium and carbon are roughly the same given equal weight.

The main difference is, that under some percentage of braking point (let us say about 50%), aluminium will start to bend, whereas carbon bar will be unaffected. When you go towards this braking point, aluminium will bend even further and finally brakes. Carbon will brake very close to this very same point when aluminium broke, but until this very moment nothing happens (no signs of failure).

Carbon brakes spectacullarry though, and probably that is why people are more afraid of it.

Please also remember that carbon does not fatigue over time, as do metals (e.g.aluminium).


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## Ciesiel (May 31, 2012)

twinkles said:


> Road bars are covered with tape, so a damaged cf bar cannot be seen and can fail catastrophically. A mountain bar is bare and can be seen if it's damaged.


This is so misleading what you write and conclusion is simply wrong .

Carbon cannot be partially damaged? It either brakes or it does not.

Carbon bar is constructed of enormous amount of fibers, combined together to make an uniform structure. Each fiber has enormous longitudinal strenght (if you took opossite sides of a fiber and tried to expand it, it would be extremely difficult to brake). Those fibers and also "stuck" together with epoxy resins, and pressed firmly in the mould in order to make all the air bubbles go out (this is the part of the process which is most tricky, and distinguishes cheap carbon products, from high end ones).

There is no place for "some" fibers to fail.

It either is OK, or it is not (it is clearly broken).


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## Gered Dunne (Feb 2, 2013)

gear is irrelevant. riding your bike more makes all the difference. but, mtb pros want a reliable bar for crashes. on the rd side, it doesn't matter much.


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## dru (Sep 4, 2006)

Ciesiel said:


> Carbon cannot be partially damaged? It either brakes or it does not.
> 
> Carbon bar is constructed of enormous amount of fibers, combined together to make an uniform structure. Each fiber has enormous longitudinal strenght (if you took opossite sides of a fiber and tried to expand it, it would be extremely difficult to brake). Those fibers and also "stuck" together with epoxy resins, and pressed firmly in the mould in order to make all the air bubbles go out (this is the part of the process which is most tricky, and distinguishes cheap carbon products, from high end ones).
> 
> ...


This is not true. I had a 16 year old carbon bar that was cracked for many years before I noticed it. The crack was right beside the brake lever and I didn't even see it till I pulled the brakes off for maintenance. I needed to get my jewellers loupe out to clearly see the broken fibers underneath the outer clearcoat. It was maybe 1 cm long. The bars had years of abuse on them, I got my money's worth for sure.

Drew


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