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Old 12-14-03, 01:51 AM   #1
jatkins679
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Snapped bars?

Cycling along and I snapped my handlebars:




Luckily, I didn't crash. But what a shock. No previous damage to the bars. Just snapped with a pretty loud sound.

Ever had this happen to you? I'm a pretty muscular/strong guy but strong enough to do this? I pull up on them hard, but that hard?
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Old 12-14-03, 02:53 AM   #2
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Nasty!!....Thats going to cost!...ow
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Old 12-14-03, 03:04 AM   #3
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wow!!!!

how strong are you???

man, that crack might have been there for a while.. Did you crash prior to the incident(just an expression)?

I bent bars before(crash), but not fracture it... how long did you use those bars? Because I have read somewhere that you need to replace your handlebars every year... or make that 2 yrs.. Or, after a crash..
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Old 12-14-03, 03:28 AM   #4
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You animal!
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Old 12-14-03, 04:28 AM   #5
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Nice, hang those up on the wall. Hope you weren't hurt when they let go.

I Broke the bars on my mountain bike a number of years ago in the same place (next to the stem). It was a simple bunny hop over a rut and when I came down the bars just snapped, nothing agro but I was going fast enough that I ended up in a gully and taco'd the front wheel as well.

I was at a bike shop where Keith Bontrager was speaking and I asked him what may have been the cause. He mentioned three things

1. Previous unnoticed crash damage.
2. Poorly sized or adjusted stem causing stress on the bar
3. Something about two different metals coming together and weakening (abrading?) each other over time. It was pretty complex and I can't say I understood it.

Seeing as I used to crash all the time, I think it was number 1 for me.

-s
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Old 12-14-03, 08:19 AM   #6
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impressive!

don't your knees hit the part of the bar that points inward?
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Old 12-14-03, 08:42 AM   #7
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Broken Bar

This is the big disadvantage of alumimum, it crystalizes under flexing and breaks more quickly than other choices.
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Old 12-14-03, 09:08 AM   #8
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What make of bars are (were) they? How old, etc. Can you give us more info in case someone else may have that problem?
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Old 12-14-03, 11:12 AM   #9
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Holy crap! I'm glad you didn't get hurt. I suspect that you had a slight fracture, and it finally gave way.
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Old 12-14-03, 11:33 AM   #10
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That's scarey.

Make sure the stem isn't an odd size, rare, but when working at a shop I'd see things that you'd think were standard just not fit. Another thing, an over-tightened handlebar can get stressed too, seen riders AND mechanics over tighten a part to silence a creak.
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Old 12-14-03, 12:59 PM   #11
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Yikes!

That happened to me a long time ago. I took a tumble when it happened, but luckily wasn't seriously hurt. After that incident, I made my peace with steel bars. I've never been that particular about weight savings. Eventually, the alloy bars get replaced with steel. The only real problem is the lack of choice among steel, especially for road bars.
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Old 12-14-03, 02:35 PM   #12
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Quote:
Originally Posted by Phatman
impressive!

don't your knees hit the part of the bar that points inward?
Only if I am turning sharply, which only happens at very, very low speed, like less than walking speed. But, yeah, I do have to watch that.
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Old 12-14-03, 02:36 PM   #13
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Quote:
Originally Posted by shecky
Yikes!

That happened to me a long time ago. I took a tumble when it happened, but luckily wasn't seriously hurt. After that incident, I made my peace with steel bars. I've never been that particular about weight savings. Eventually, the alloy bars get replaced with steel. The only real problem is the lack of choice among steel, especially for road bars.
Good suggestion, I think I'll look into steel. I don't care about the weight difference, I'm 230 pounds already, it's not going to make a bit of difference for me.
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Old 12-14-03, 02:50 PM   #14
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Quote:
Originally Posted by jatkins679
Only if I am turning sharply, which only happens at very, very low speed, like less than walking speed. But, yeah, I do have to watch that.
Same here... especially when standing, manoevering into my driveway.

Oooo... I've got the same bars. Specialized (designed by Scott). I've been thinking of replacement just because I've got so many miles on them. That picture reminds me to shop for new bars.
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Old 12-15-03, 12:17 AM   #15
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Did the thing snap "away" from you? Seems like there was a pressure point where the handle bar goes into the stem on the side towards you and fatiguing on the road eventually caused that spot to yield and everything else went along with it.
Do you usually put a lot of pressure on it or hop and land on it? Seems like a freak accident, I'm glad you're ok, must be scary as hell to have the thing come off in your hands.
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Old 12-15-03, 12:45 AM   #16
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How in the world did you pull that one off?
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Old 12-15-03, 06:34 AM   #17
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Looks like stress riser-meets-metal fatigue.

A stress riser is a gouge or even a small scratch in the surface of a material. If there's a lot of material (as in heavier handlebars), it's not as big of an issue. Or, if the material is more ductile (such as steel handlebars) it again becomes less of an issue.

Basically, if there's a stress riser, you're trying to send the same amount of force through a smaller section of material. Now the area around the stress riser is under more strain, which further propagates a crack (and increases the local strain, and propagates......)

Throw metal fatigue into the mix and it just gets ugly.

The stampings in that area (brand logo, etc.) aren't as bad of a stress riser because the material isn't actually missing; it's only been compressed.

In the days before surface treatments like shot peening, the aircraft industry used to put a very fine polished finsh on high stress engine parts to reduce the chance of stress riser and its crack propagation. We actually still do it on our lightened con-rods that we make for our motorcycle race team.

Another problem is with most stems that I've seen is the sharp edge that they have where the bar enters it. It doesn't actually "cut" into the handlebar (except under flexure, such as pulling and pushing on the bar ) , but it does increase the localized stress at that point. If that area were just slightly flared with as little as 1mm of radius, it would probably increase the bar's lifespan... Or least increase the safety margin.

All of that theoretical b.s. aside, I'm glad to hear that made out unscathed... So hows the laundry?

-Erik
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Old 12-15-03, 06:59 AM   #18
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Bars break. I deal with 2 or 3 a season at least. That's one reason I change my bar tape at least every season so I can examine the bars. This last summer, one of the hammerheads in my area had me re-wrap his bars. When I pulled the tape off, I found that his sweat had eaten several holes in the top of the bar. He was lucky. I put the bars up on my "Wall of Shame", a special place to show off the parts that are deficient, broken, and mangled.

If you are a big strong rider who pulls up hard in sprints or when standing, you should be examining your bars on a regular basis. Any little hairlines are suspect. From the picture, I'd say you were damn lucky.
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