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sonyisdope said:
What is this bulge in the middle of all the new handlebars I'm seeing? Is it necessary? WHY OH WHY!
Do you have an example? Most bars have had a center bulge for years because the stem clamp is larger diameter than the grip area.
 

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Might I suggest...

sonyisdope said:
What is this bulge in the middle of all the new handlebars I'm seeing? Is it necessary? WHY OH WHY!
You bring your bike in to get the BB shell tapped with a case of Guinness in your hand for the wrenches. Then spend some time picking their minds for some of these questions.

The bulge in the middle of the bar is to bring the bar up to the standard OD for the stem interface.

Ken
 

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uofabill
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It's the new 31.8 mm dia bars

That's what they are, but why and what the purpose is, is another question. I have no idea. It seems to me that it is something that started on road bikes and has made it's way to mtn bikes. I have read about them in some previous threads on these boards. I think there was mention about those bars being stronger but since it is only the bulge where they clamp to the stem I don't know how that would make the whole bar stronger. You have to get a new stem that accomodates that bulge.
Re: carbon bar failure, what I read here is that the most common location of failure is where the brake levers and or brake/shifter pods clamp onto the ends of the bars. I have read some instances of carbon bar breakage at the stem clamp but it doesn't seem as common. With metal bars I don't know what the benefit of that bulge would be?
 

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Discussion Starter · #6 ·
uofabill said:
That's what they are, but why and what the purpose is, is another question. I have no idea. It seems to me that it is something that started on road bikes and has made it's way to mtn bikes. I have read about them in some previous threads on these boards. I think there was mention about those bars being stronger but since it is only the bulge where they clamp to the stem I don't know how that would make the whole bar stronger. You have to get a new stem that accomodates that bulge.
Re: carbon bar failure, what I read here is that the most common location of failure is where the brake levers and or brake/shifter pods clamp onto the ends of the bars. I have read some instances of carbon bar breakage at the stem clamp but it doesn't seem as common. With metal bars I don't know what the benefit of that bulge would be?
Yes, that is what I'm talking about. An LBS near me has a few '05 Treks, and they all have the 31mm clamp area. They also have some new Easton bars that have this too. I was just wondering why they are making this change, and if it is a new standard or something.
 

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rigidity

the rigidity of a tube increases with the cube of its radius. or is it with the cube of its diameter? I forget, one or the other.
that's the principle behind fat tube cannondales and their ilk. it adds a alot of rigidity without the weight penalty of making the tube wall thicker, which would be the other way to increase a tube's rigidity.
also, aluminum doesn't like being flexed and shows its anger by breaking. so a slightly fatter tube is a lot more rigid, and thus a lot less likely to become angry.
 

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bulC said:
the rigidity of a tube increases with the cube of its radius. or is it with the cube of its diameter? I forget, one or the other.
that's the principle behind fat tube cannondales and their ilk. it adds a alot of rigidity without the weight penalty of making the tube wall thicker, which would be the other way to increase a tube's rigidity.
also, aluminum doesn't like being flexed and shows its anger by breaking. so a slightly fatter tube is a lot more rigid, and thus a lot less likely to become angry.
...and also interface rigidity. It promotes stiffness in the bar/stem interface -- less give when the big boys get to rocking up a climb.

 

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It'a actually not new. For years Tioga has used oversize centers on their 286 bars and Cube stems. They are 28.6 diameter. I've been using them on all my bikes for the last 5 years.
 

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Alpinestars too

FISHLEG said:
It'a actually not new. For years Tioga has used oversize centers on their 286 bars and Cube stems. They are 28.6 diameter. I've been using them on all my bikes for the last 5 years.
Don't know if they were the first to come up with the idea, but Alpinestars had oversize bulge bars and matching stems back around '90.
 
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