['size]

wrench got away from me installing my many years old bars. it appears to just be clear coat from the pieces i pulled off but i was debating replacing anyway due to a previous crash that did the same thing in another location along with some minor scuffs, plus the age.

so...trust it or not? if not..what 750mm x 31.8 x 20mm or less rise is the hot ticket these days? i'm perfectly happy with the havoc and had pretty much planned to replace with the same bar at some point.

click for zooms:

 

[kidwoo]

Fuck no those are eastons.

You know what the hot replacement is? Any aluminum bar that you don't have to worry about slipping with a wrench near. At this point I've seen just about every major brand of carbon bar almost kill someone. I've seen two aluminum bars break in my 20 years of riding mountain bikes. It's what, 80 grams?

Get a handle bar that you don't have to ask other people about your safety because you're that concerned with it.

 

[jstuhlman]

Fuck no those are eastons.

You know what the hot replacement is? Any aluminum bar that you don't have to worry about slipping with a wrench near. At this point I've seen just about every brand of carbon bar almost kill someone. I've seen two aluminum bars break in my 20 years of riding mountain bikes. It's what, 80 grams?

Get a handle bar that you don't have to ask other people about your safety because you're that concerned with it.

was thinking about @kidwoo 's crabon deth handlebar comments the other day during a particulalry rough descent. get out mah head, man!

 

[kidwoo]

He asked me if I would ride them.

You'll be happy to know I rode a full day at whistler last year on some sixC bars and didn't really worry about them. I wasn't going to own them for two years though.

Just ask yourself....you ever remember discussions about someone using 'proper torque spec' on some brake levers when they break an aluminum bar? Probably not. There's a reason for that.

But eastons and renthals are shit. Even when they're not nicked.

 

['size]

gets scared, pulls sunline V1's out of the 'old shit' drawer...

 

[kidwoo]

Here's your next nightmare

Apparently that's a thing with road bikes. But the good thing about aluminum is that you can see shit by looking at it.

 

[gemini2k]

Here's your next nightmare

Apparently that's a thing with road bikes. But the good thing about aluminum is that you can see shit by looking at it.

Da fuq??? Is that the glue or sweat destroying the carbon somehow?

 

[Westy]

Put some sunblock on it and it will be fine.

 

[kidwoo]

That's an aluminum bar. With some gross ass roadie sweat I suppose.

Fair and balanced yo.


FWIW, I rode road bikes to an unhealthy degree in FL (with salty air) and am certainly a sweater in humid weather and I never saw any thing like that on my bikes. A friend of mine brought this phenomenon to my attention a few years ago when I was talking shit on carbon handlebars. It's gotta be a forearm roadie tape thing. I've seen some corrosion on aluminum bars but nothing anywhere near that. At this point I'm just fucking with jsthulman because as he's well established, he's never broken a bike part, and therefore anyone who does is just crazy.

 

[jstuhlman]

oh schnapp...i'm totally stealing that idea and making biking-specific crabon sunblock, mothafucka! either that or uv-repellant frame and component skinzzzzzz

not never broken a bike part...just not mah crabon bars...YET

 

[Jm_]

Do like I do. Don't try to save grams, buy a freaking carbon DH bar for your AM bike, it's damn thick and you could easily break bones if you used it for self defense. Same weight, but many times the strength.

 

[kidwoo]

Don't try to save grams, buy a freaking carbon DH bar

 

[Westy]

That's an aluminum bar. With some gross ass roadie sweat I suppose.

Fair and balanced yo.


FWIW, I rode road bikes to an unhealthy degree in FL (with salty air) and am certainly a sweater in humid weather and I never saw any thing like that on my bikes. A friend of mine brought this phenomenon to my attention a few years ago when I was talking shit on carbon handlebars. It's gotta be a forearm roadie tape thing. I've seen some corrosion on aluminum bars but nothing anywhere near that. At this point I'm just fucking with jsthulman because as he's well established, he's never broken a bike part, and therefore anyone who does is just crazy.

My retired old Turner has what looks like giant rust bubbles all over the top tube. Bust open the powder coat and they are full of white powdery oxide. I can only assume scratches allowed my toxic sweat in and some terrible chemistry took place.

 

[kidwoo]

I can only assume scratches allowed my toxic sweat in

Either that or liberalism.

 

[Westy]

Either that or liberalism.

Gay marriage made my bike rust. The science works out.

 

[jstuhlman]

you foul, sweaty, tyrant . . . #aluminumframesmatter

 

[Udi]

Put some sunblock on it and it will be fine.

Came in to make the sunblock comment, but it appears this problem is already solved.
Next thread.

 

[saruti]

how can you trust a carbon bar?
I crashed hard when my Easton failed on me on a big jump. luckily I only got some bruises..
the companies test the bars without the grip or brakes mounted. so... there is no scratch on the bar when they test it. this is not the situation in the real world... just after you get your lock on grips and\or brakes on the bar. there are small scratches.
you know how you cut glass? you make a scratch on it. and than it brake exactly on that scratch.
so....

 

[HAB]

My retired old Turner has what looks like giant rust bubbles all over the top tube. Bust open the powder coat and they are full of white powdery oxide. I can only assume scratches allowed my toxic sweat in and some terrible chemistry took place.

Back in my shop days, we had a customer who came in because all the cable stops on the top tube of his carbon Cervelo had fallen off. A closer inspection revealed that they were held on with aluminum rivets, which had just corroded to shit like that. The ones elsewhere on the bike (i.e. not in the path of his sweat drips) were fine.

 

[jackalope]

Regarding the sweat corrosion thing, I almost melted my face off recently when I replaced the grips on an old DH bar (alum) and inhaled the vile miasma wafting off the area where the grips were. It was like concentrated donkey urine crystals or something...dipped both ends in some mineral spirits which seemed to help, but in truth I probably need to just send the bar to kidwoo as a "gift".

Also had a buddy whose toxic monkey sweat molecularly bonded his grips to the bar, and he ended up having to get a whole new bar after failing to remove the grips with vice grips.

I think I'm going to design a bar with tiny little drain holes under the grip area, then stuff a proprietary tampon in there which you change every month or so. The bar end string may be a little off putting tho.

 

[Jim Mac]

^^^^ VRT^^^
Vibration Reducing Tampon!!!

sumpin' like dis:

 

[canadmos]

The sweat thing is interesting. I sweat enough that on hot day, I can see it running down my seat tube, which then grabs dirt. I stop regularly and squeeze buckets of sweat out of the padding in my helmets (curiously, never from my full face though..). The indentations on my stem are often filled with sweat. Though even through all of that, I've never had any bars or other parts corrode. Maybe I wash my bike too often?

As for those bars, there is no way I'd use damaged bars, no matter what material they are made out of.

 

[jackalope]

^^^^ VRT^^^
Vibration Reducing Tampon!!!

sumpin' like dis:

Hellz yeah...That's so enduro

I wonder if we could at least make crabon fiber strings to class things up a bit (i.e. validate why the replacement 'pons cost $50 per pair)

 

[SuboptimusPrime]

I also found a bunch of white fuck under my grips recently. How that stuff got inside my lock ons (which I kinda thought were a tube of impermeable plastic covered with grippy rubber) is beyond me. Does not appear to be corroding the aluminum, rather just an accumulation of donkey urine crystals as Jackalope noted. If someone actually proves that sweating on aluminum renders it unsafe I'm quitting bikes.

 

[norbar]

gets scared, pulls sunline V1's out of the 'old shit' drawer...

The early gen 6061 ones that bent on the first crash?

 

['size]

The early gen 6061 ones that bent on the first crash?

honestly not sure, but i think they are a later model based on the graphics. ran them on a few bikes over the years and never crashed. i'll throw the damaged carbon easton's in my pack just in case...

 

[jimw]

FWIW, I rode road bikes to an unhealthy degree in FL

 

[jackalope]

Well, it's probably either that or rollerblading in a thong at various Miami beach fronts, so all things considered...

We are talking about fucking Florida...

 

[StiHacka]

Take the handlebar off some sweet jumps and let us know how it felt.

 

['size]

Take the handlebar off some sweet jumps and let us know how it felt.

no sweet jumps in my neighborhood but i did pedal as fast as i could and slammed into the curb earlier. seems fine. rebound on the pike was a bit slow though...

 

[kidwoo]

Well, it's probably either that or rollerblading in a thong at various Miami beach fronts,

Like those are somehow mutually exclusive. Pssh

 

[sbabuser]

Tough to tell from the picture, but yeah, I'd probably ride it, unless I saw strands cut.

 

[Westy]

Well, it's probably either that or rollerblading in a thong at various Miami beach fronts, so all things considered...

We are talking about fucking Florida...

Overpass KOMs

 

[sethimus]

Well, it's probably either that or rollerblading in a thong at various Miami beach fronts, so all things considered...

We are talking about fucking Florida...

will overflooded soon anyways

 

[Harry BarnOwl]

wrench got away from me installing my many years old bars. it appears to just be clear coat from the pieces i pulled off but i was debating replacing anyway due to a previous crash that did the same thing in another location along with some minor scuffs, plus the age.

so...trust it or not? if not..what 750mm x 31.8 x 20mm or less rise is the hot ticket these days? i'm perfectly happy with the havoc and had pretty much planned to replace with the same bar at some point.

click for zooms:

Composites engineer here. The amount of damage you've done depends on a) how hard you hit it and b) how small the surface area of the thing you hit it with is. Can you elaborate? If you've just scuffed them it's probably nothing to worry about - as you say you've probably just taken some clear coat off. Fill it in with some epoxy, leave it to cure properly and then sand it down flush. If you've actually hit them with any amount of energy then I'd be wary.

One of the biggest problem with composites (amongst many others) is barely visible impact damage (BVID). Here's the top side of a flat laminate after being hit with a ball hammer:

And here's the underside:

Not saying this will happen to yours, but I've seen carbon handlebars go snap on two separate occasions; one ended in damaged shoulder ligaments and the other a broken rib and a concussion. Both bars snapped in the same place: the bend where the bar rises. I suspect this is because of the variation in cross-section thickness through the bar, with it being thicker where it clamps into the stem and where your controls/grips are. This means that there are ply drops (where the number of lamina are "stepped down" to achieve a drop in thickness) towards the curve/rise in the bar, making it a natural weak spot.

With the current level of understanding (or lack thereof) of composites design and manufacture in the bike industry, I am extremely wary of composite bars as it's the one component I would not want to take any risks with.

 

[Udi]

Hey @Harry BarnOwl could you recommend an off-shelf clearcoat that could be applied to carbon bars after scuffs and scrapes, ideally of a strength and hardness similar to the factory application?

I'm talking about damage where little to no impact is involved but the clear coat is damaged or removed leaving the carbon partially/completely exposed (but not really any deeper than that). I've often thought it would be nice to fill any minor voids with epoxy and re-clearcoat the entire part/s sometimes.

Perhaps a few suggestions of epoxies and clear coats would be useful (given this is a global community and not everything is available everywhere), since there are a myriad of both products out there and I've often wondered which ones are/aren't suitable for carbon MTB products.

As a sidenote - for whatever it's worth, all recent carbon bar breakages I've seen have been directly at the lever clamping zones (different to your experience it would seem), so I think failures are often caused by stress risers generated by sharp edges of controls and/or cuts generated during rotation in crashes etc. I'm of the strong opinion that some kind of load distribution should be engineered into the controls themselves where they clamp to the bars - eg. a very hard plastic sleeve wider than the clamps themselves (similar to motorbike levers).

Appreciate your thoughts.

 

[lobsterCT]

Hey @Harry BarnOwl could you recommend an off-shelf clearcoat that could be applied to carbon bars after scuffs and scrapes, ideally of a strength and hardness similar to the factory application?

I'm talking about damage where little to no impact is involved but the clear coat is damaged or removed leaving the carbon partially/completely exposed (but not really any deeper than that). I've often thought it would be nice to fill any minor voids with epoxy and re-clearcoat the entire part/s sometimes.

Perhaps a few suggestions of epoxies and clear coats would be useful (given this is a global community and not everything is available everywhere), since there are a myriad of both products out there and I've often wondered which ones are/aren't suitable for carbon MTB products.

As a sidenote - for whatever it's worth, all recent carbon bar breakages I've seen have been directly at the lever clamping zones (different to your experience it would seem), so I think failures are often caused by stress risers generated by sharp edges of controls and/or cuts generated during rotation in crashes etc. I'm of the strong opinion that some kind of load distribution should be engineered into the controls themselves where they clamp to the bars - eg. a very hard plastic sleeve wider than the clamps themselves (similar to motorbike levers).

Appreciate your thoughts.

Not an expert, but I've used the west system products to build carbon or fiberglass fishing rods and more recently to re-enforce the flimsy cta arch on my dvo emerald. Seems to work well, and the products are easily available as they are the go to in the boat repair industry.

 

['size]

Composites engineer here. The amount of damage you've done depends on a) how hard you hit it and b) how small the surface area of the thing you hit it with is. Can you elaborate?

the most recent incident was tightening the stem steerer clamp bolts with a park 4-5-6 Y wrench which wasn't all the way in the bolt head - it slipped out of the bolt head and spun into the bar. i'm guessing it went from 10 to 2 o'clock with whatever force one would use when spinning that wrench during the initial tightening of the bolt - i was not near max torque value, it was pretty much free-spinning.

the first incident was during a slow OTB into some shrubs, soft mud and a downed tree. it was right after a rain storm and the ground was pretty moist for the desert. i was initially concerned with this as the brake lever and shifter were pretty caked with mud and debris but i removed the brake and shifter clamps and saw no indication of damage - just the slight indention the clear coat gets from the tightening of the clamps.

 

[Harry BarnOwl]

Hey @Harry BarnOwl could you recommend an off-shelf clearcoat that could be applied to carbon bars after scuffs and scrapes, ideally of a strength and hardness similar to the factory application?

I'm talking about damage where little to no impact is involved but the clear coat is damaged or removed leaving the carbon partially/completely exposed (but not really any deeper than that). I've often thought it would be nice to fill any minor voids with epoxy and re-clearcoat the entire part/s sometimes.

Perhaps a few suggestions of epoxies and clear coats would be useful (given this is a global community and not everything is available everywhere), since there are a myriad of both products out there and I've often wondered which ones are/aren't suitable for carbon MTB products.

As a sidenote - for whatever it's worth, all recent carbon bar breakages I've seen have been directly at the lever clamping zones (different to your experience it would seem), so I think failures are often caused by stress risers generated by sharp edges of controls and/or cuts generated during rotation in crashes etc. I'm of the strong opinion that some kind of load distribution should be engineered into the controls themselves where they clamp to the bars - eg. a very hard plastic sleeve wider than the clamps themselves (similar to motorbike levers).

Appreciate your thoughts.

Hey @Udi, sorry for the late reply. My area is thermoplastic-matrix composites (like PEEK) rather than thermosets (epoxy etc), but I'll do my best. As far as epoxies go, I don't see why you couldn't use any off the shelf two-part epoxy. It won't contribute anything to the strength of the area unless it's properly consolidated anyway (eg vacuum bagged and completely cured), so really it's just there for surface protection. As a general note, there should be no compatibility issues on the chemical side of things between epoxy you can get off the shelf and the stuff used to make the components. Not all epoxies are created equal, but unless you get into the high-performance end of things ($$$) most will be of similar properties in terms of strength, CTE, glass transition temperature etc.

A clearcoat on top of that is a good idea as epoxies will absorb moisture over time. Again with the clearcoat, not my area so don't take this as gospel, but I don't see why you couldn't use any acrylic-friendly automotive clear coat off the shelf, just make sure it's got some UV resistance and doesn't absorb moisture. This paper gives you an idea about what effect environmental conditions can have on your matrix over time, and how that has a knock-on with the composite as a whole. Best to ask people who work with the stuff hands on for specific recommendations - @lobsterCT's suggestion seems like a good shout, especially if it works for marine applications.

Yeah the clamping surfaces are where you would expect them to go. Composites are terrible at dealing with bearing stress and have very low through-thickness strength. By the looks of things, the thickness of the laminate throughout some bars is varied and seems to be thicker at the ends where the grips/controls are. I've also wondered about an additional sleeve bonded over the top.

the most recent incident was tightening the stem steerer clamp bolts with a park 4-5-6 Y wrench which wasn't all the way in the bolt head - it slipped out of the bolt head and spun into the bar. i'm guessing it went from 10 to 2 o'clock with whatever force one would use when spinning that wrench during the initial tightening of the bolt - i was not near max torque value, it was pretty much free-spinning.

the first incident was during a slow OTB into some shrubs, soft mud and a downed tree. it was right after a rain storm and the ground was pretty moist for the desert. i was initially concerned with this as the brake lever and shifter were pretty caked with mud and debris but i removed the brake and shifter clamps and saw no indication of damage - just the slight indention the clear coat gets from the tightening of the clamps.

By the sounds of things I doubt you've damaged them structurally. As a general rule of thumb sharp impacts (like smashing them off of a rock) are the ones to be wary of. You should be able to get away with a little bit of epoxy to fill it in then a bit of clearcoat over the top if you're feeling fancy.

 

['size]

By the sounds of things I doubt you've damaged them structurally. As a general rule of thumb sharp impacts (like smashing them off of a rock) are the ones to be wary of. You should be able to get away with a little bit of epoxy to fill it in then a bit of clearcoat over the top if you're feeling fancy.

.

so if i say fuck it and run them as it i should be good, just not pretty?