[Closed] Is this anything to be worried about? Carbon bar content...

looks like just lacquer damage. I am guessing the black spots are a transfer under the lacquer as the lacquer seems to have detached around them, possibly due to an adhesive on the dots.

Odd, first post disappeared?

Only asked if s/hand or not as if its not, at least you know if its suffered abuse... as you used it. Not someone else selling it on. 🙂

Yep - had problems with the photo, and mods deleted first post.

They're secondhand, been used for XC riding only - and only for a few months.

rickon

Yep - had problems with the photo, and mods deleted first post.

They're secondhand, been used for XC riding only - and only for a few months.

Ah, not me going mad then.

Looks cosmetic to me to be honest. That said, Ive only ever had 2 carbon bars and had a bad experience with the second (cheap) one.

Been a luddite since and stuck to alloy. No doubt some other peeps on here will have had far more experience with carbon to help you out though.

Looks like a lock-on grip mark? I can see a small groove that looks a bit like the clamp has rotated a bit and cut the lacquer more than overtightening.

That said, I would be happier if you said they were 100% yours and never overtightened but carbon is pretty tough and people do worry a lot more than they need to.

I've got some carbon bars which were marked like that within a week of fitting.

Used them for another 4 years after that. Only retired them to fit something shiny and new. The installation marks (and a load of other marks!) were just in the lacquer.

As long as it's not a) a cheap nasty bar from a manufacturer with only a vague idea about QC or b) a silly light bar.

I'd carry on regardless.

As long as it's not a) a cheap nasty bar from a manufacturer with only a vague idea about QC or b) a silly light bar.

Just what I was gonna say - I've ridden carbon bars with much worse damage.

I'd be more worried about what has corroded your Park Tool dish!

The general consensus seems to be to just ride it and not worry.

I can feel the mark with my fingernail all the way round, would that not weaken the carbon at all?

It's a bit like someone's taken a Stanley knife and marked around the bar.

Here's another closer photo:

[img] [/img]

It looks like just a crack/mark in the lacquer, you can see where the sticker/decorative spots have also caused the lacquer to lift........

TBH i bet you could polish 99% of that out with some T-Cut and 30 seconds.

If you're worried, stick it in a vice and bash it quite hard with a rubber mallet as a stress test*.

*note: I am not an engineer

looks as others have said, to be a laquer mark.

Only potential problems I've encountered was with gripshift and carbon bars. Continued rotation and leaning on the shifter produced a nice 0.5mm dent on my easton monkeylites. I stopped using them after that!

I'd echo all the above.

Other than that though, when fitting stuff to carbon bars, deburr the contact surface and apply carbon assembly paste to the bar surface area where it will be attached. Protects and also allows you to apply a lower torque without it slipping on the bar, which helps avoid gouging the bar. The paste is usually recommended or required by manufacturers where carbon is involved, and even recommended for ali stuff. Also ali + carbon it helps avoid corrosion with the mix of materials.

The spots aren't decals, it's the 'holes' in the decorative weave of the top layer.

They've gone white where something has scratched the laquer and allowed moisture to get in and blister it slightly (uncured epoxy forms ions, so osmosis draws water in). If you want reassurance, you should see the tips of carbon dinghy masts that get sailed anywhere shallow. The laquer is usually completely missing through a mix of being scraped along the bottom and left out in the sun for UV to do it's damage. The advice is to sand it down to the bare carbon fiber then re-varnish!

One of the best things about carbon is it's really hard for cracks to propogate, score a bit of aluminium and it'll bend and snap neatly at the score, score carbon and it'll probably break wherever it would have anyway regardless of the score.

[img] [/img]

Now ^ that looks like a good old bit of overtightening!

no probs. probs

[img] [/img]

What is it with Jims?!

[img] [/img]

thisisnotaspoon - Member
The spots aren't decals, it's the 'holes' in the decorative weave of the top layer

hmm, not sure about that. Pretty sure those dots are a decal layer under the lacquer.

You should see my old monkey DHs, they looked like a dog had chewed on them

I've got 3 pairs of carbon bars and they all look like that, personally I'd have no worries running them.

If they've delaminated they will sound hollow when you give them a tap, however I very much doubt that.