Deda carbon bars crushed?

Discuss light weight issues concerning road bikes & parts.
drchull
Posts: 377
Joined: Sat Jul 30, 2011 6:38 pm

by drchull

My experience with white parts (in particular seat posts) is they slip and that scores the paint which is what it looks like here to me. If you are feeling an indent that is not just the chipped paint/clearcoat I wouldn't use them.
If I wasn't sure I would probably re-install in the stem, immobilize front wheel and "sprint" on them i.e. put as much force into them with my hands as I could. I am envisioning standing with wheel between legs not riding down road. When I broke my bars in the past they snapped off fairly easily. While not definitive this should at least be reassuring that they are solid.

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MisterEd
Posts: 150
Joined: Sat Feb 14, 2009 2:53 am
Location: Scotland or London

by MisterEd

I've had exactly the same problem with two sets of Deda Presa bars.

I used them with a deda zero stem, with carbon paste and a torque wrench.

Both time Deda replaced them under warrenty but I've now gone back to using their zero 100 barsto save the trouble of this happening again.

I'll see if I can dig out the pics I took when it happened but interesting to know it's not just me that this happened to.

by Weenie


latman
Posts: 123
Joined: Thu Aug 20, 2009 12:44 pm

by latman

alloy bars can have problems too ! These were selcof using an FSA stem
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selcofbars.JPG

artray
Posts: 1365
Joined: Fri Oct 07, 2011 2:08 pm

by artray

I had some Zipp carbon bars that had marks very much like yours . The bars gave out on me , I was lucky not to have a bad crash . If your 100% sure its just the clear then they are fine , but if you have any doubts then it's not worth the risk .

daj
Posts: 246
Joined: Mon Oct 12, 2009 6:36 pm

by daj

Were the bolts dry or greased when you used the torque wrench? 6 Nm on greased bolts is a lot more force than 6 Nm on dry bolts.

leosantos
Posts: 115
Joined: Thu Feb 09, 2012 12:41 pm

by leosantos

daj wrote:Were the bolts dry or greased when you used the torque wrench? 6 Nm on greased bolts is a lot more force than 6 Nm on dry bolts.


do you mean the bolt head or the swirling body? I´ve greased bolt's heads completly in some occasion and would be surprised if it makes a difference.. then again, Im up for advice if it is really necessary, and I bought second hand parts the came with the whole body of the bolts greased and used them with no issues

Dcgriz
Posts: 42
Joined: Wed Oct 19, 2011 4:50 pm
Location: Poormans Canyon

by Dcgriz

daj wrote:Were the bolts dry or greased when you used the torque wrench? 6 Nm on greased bolts is a lot more force than 6 Nm on dry bolts.


+1. As much as 25% more

Camilo
Posts: 361
Joined: Sun Mar 23, 2008 7:31 pm

by Camilo

latman wrote:alloy bars can have problems too ! These were selcof using an FSA stem

Image
I have EXACTLY the same damage on some mid-grade Ritchey aluminum bars, using a matched Ritchey stem. In other words, not lightweight, fragile gear. I think the bars weigh ~300 grams FWIW

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dog
Posts: 38
Joined: Mon Oct 29, 2012 7:57 pm
Location: Flanderia, Belgie

by dog

Excuse me for going off-topic for a little.
Any comments on the Zero 100 bar? In the past I've seen people weren't finding it stiff enough, at least compared to the Newton bar. What's the view nowadays (ie. current generation Zero 100)?

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Lig
Posts: 317
Joined: Sun Dec 19, 2010 3:57 pm
Location: UK

by Lig

Hi Iscarrr,

Its a tough call. I had a really bad crash and my bike came down on the stem so the stem top cap bolt was bent and the top 5mm washer was snapped, anyhow the carbon bars were absolutely fine, just a light scuff at one end where they had worn through the tape but no cracks at all.... anyhow, I built a new frame up put the bars on, jumped up and down on them, twisted them everything, and they didn't fail.... I did one ride and all was fine, however in my mind i just kept thinking 'these have been through a severe impact.. what if....' so after this ride I replaced them and binned them. I think they will be fine but it depends if your head will be fine? My advice is to bin them - you will not think about it then and its much better to be safe... for what a couple of hundred quid?!

Lig.

boots2000
Posts: 1443
Joined: Mon Oct 15, 2007 9:28 pm

by boots2000

I bought a set of bontrager bars off ebay a while ago. WhenI got them they had the same kind of indentation that your bars do.
I took them to my lbs and had the Trek rep look at them. He said they were fine.
It is just clear coat or that textured paint stuff that gives it grip.

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djconnel
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by djconnel

1 1/4 inches = 31.75 mm (exactly). So calling it 31.7 or 31.8 is all in the wash. That's within sample-to-sample variation, typically, anyway.

artray
Posts: 1365
Joined: Fri Oct 07, 2011 2:08 pm

by artray

From that photo it looks like the clear coat nothing else . If you want to be sure mask off the sides and wet and dry the paint off and you will then will be able to see if the carbon has cracked or splintered.
It would look pretty cool as well .

petepeterson
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Location: 604

by petepeterson

^ that's what I would do.

Is the penny tapping test as simple as listening for a variation in sound or something more specific?

Valbrona
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Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

I have never assumed that you should tighten the clamp to the same torque with carbon bars as with metal bars.

by Weenie


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