Are Carbon bars ok?

[Teamsloan]

FSA K-Force bar on my hardtail (bought the bike used and the bar came with it) standard 3K weave carbon at least on the outside.

Easton Haven bar on my Blur that I bought new has a unidirectional finish layer, not sure about the inside layers.

Both bars have been great and the K-Force is now on my sons little project bike.

While a M3 bolt looks tiny it's still fully capable of tightening a clamp beyond the torque specs for the bar. ALWAYS use a torque wrench when mounting parts to carbon. And yes, I prefer to use a beam style torque wrench. Unless of course you prefer to keep your levers loose so that they rotate in the event of a crash.

There are so many people running carbon bars out there with zero issues, and I would argue that they are by far the majority. Like most things they can fail. It's a calculated risk. Glad you're ok.

[ATXZJ]

1 hour ago, HoneyBadger said:

Seth, I think Chromag is the problem, not all carbon bars. Buy Renthal Carbon Fatbar, you'll be happy.

Wife's bikes have had chromag cutlass bars for a couple years and they are a bit flexy for sure. However, she weighs nothing and is a XC/Trail rider at best so fingers crossed. Another bike has performance house brand carbon bars (i think same company that does ritchey) and last pair are enve DH. Also had some promax/box bars on my X bike that took some abuse and REALLY softened up the ride. No issues (yet).

At this point, I dont torque them to spec as the brake levers and shifter actually feel like they are over-tightening the bars. Combine that with a clamp that doesn't apply equal force across the circumference of the bar and its trouble for sure. Carbon paste and tighten till it feels like just enough. Stem clamp bolts are however torqued to spec. You would have almost NONE of these issues with a good aluminum bar like the ones offered from thomson etc.

2nd the renthal comment but wish theyd dial down the gold accents.

[throet]

16 hours ago, AntonioGG said:

This is actually an interesting point.  I think it's easy to create a lot of pressure and damage a tube of any kind, but I wonder how much it would take.  I bet it's less than it takes to strip a 3mm bolt.  The fact it took zero torque to remove tells me it was crushed.

I know I don't even use the cheap clicker torque wrench for my bar,  I use only a beam wrench on my levers and bar ends.  I used to exclusively ride Truvativ (really not that expensive) but my latest bike came with an Enve.  So far so good.  I put about 10k miles on the Truvativ that was on my Tallboy, now it's my wife's bike.  Still looks good.

I was also looking at the Chromag page.  From the info on their website, it's not a company that inspires confidence in me (translate as: I wouldn't buy from them).  They have a lot of sales people, and graphic designers, and apparently one--maybe--technical dude.  I didn't see an engineer listed on there.  I was concerned with the unidirectional fiber they claim is good for their bars.  I'm no ME but I believe I'd want parallel fibers along the length for shear strength, as well as circumferential fibers for crush strength.

Is there a "rule of thumb" torque setting for anything attaching to carbon bars? I don't recall if any of my components have values stamped on them, and even if they did those values would likely vary for carbon. I tend to google search when I'm tightening anything on my bars, and seem to recall using something between 3-4 nm. My grips, which only have inside locks, can still spin after tightening to recommended torque, but I've resisted tightening them any further. Hopefully the occasional spinning of the lock ring is not in itself compromising the integrity of the bar.  

[AntonioGG]

16 minutes ago, throet said:

Is there a "rule of thumb" torque setting for anything attaching to carbon bars? I don't recall if any of my components have values stamped on them, and even if they did those values would likely vary for carbon. I tend to google search when I'm tightening anything on my bars, and seem to recall using something between 3-4 nm. My grips, which only have inside locks, can still spin after tightening to recommended torque, but I've resisted tightening them any further. Hopefully the occasional spinning of the lock ring is not in itself compromising the integrity of the bar.  

Yes, the bars have specs and so do the things with clamps.  I have found that there are often incompatibilities.  Some bars are rated for 3-4Nm while a lot of clampy things are rated at 5-7Nm.    As an example, I run bar ends.  I believe those are 6-7Nm.  My older TruVativ bars specifically say no bar-ends allowed.  I machined aluminum pieces to fit inside the area where the bars clamp to deal with that issue.  As to the other things like brake levers, I go with the bar specs and use carbon paste.  It works well to keep shifters and levers from spinning.

[throet]

1 minute ago, AntonioGG said:

Yes, the bars have specs and so do the things with clamps.  I have found that there are often incompatibilities.  Some bars are rated for 3-4Nm while a lot of clampy things are rated at 5-7Nm.    As an example, I run bar ends.  I believe those are 6-7Nm.  My older TruVativ bars specifically say no bar-ends allowed.  I machined aluminum pieces to fit inside the area where the bars clamp to deal with that issue.  As to the other things like brake levers, I go with the bar specs and use carbon paste.  It works well to keep shifters and levers from spinning.

Thanks. I see other references to carbon paste as well, and didn't even know it was a thing. I'm going to check into that for sure. 

[RidingAgain]

36 minutes ago, AntonioGG said:

I machined aluminum pieces to fit inside the area where the bars clamp to deal with that issue. 

 

I just spoke about something like that in my thread on breaking handlebars.

[TheX]

13 minutes ago, RidingAgain said:

I just spoke about something like that in my thread on breaking handlebars.

Why didn't you talk about it in this thread?

[FJsnoozer]

Is there a "rule of thumb" torque setting for anything attaching to carbon bars? I don't recall if any of my components have values stamped on them, and even if they did those values would likely vary for carbon. I tend to google search when I'm tightening anything on my bars, and seem to recall using something between 3-4 nm. My grips, which only have inside locks, can still spin after tightening to recommended torque, but I've resisted tightening them any further. Hopefully the occasional spinning of the lock ring is not in itself compromising the integrity of the bar.  

 

Yes!

 

And do NOT use the torque setting on the stem, because that relates to torque on an aluminum bar. All of these products should have a torque setting available or else you should check into it with the manufacturer.

 

I find that none of my carbon parts require the max torque to stay put, even my seatpost. (Except for my KS lev seat rails but I was told specifically by their tech to exceed 8nm)

 

Use proper carbon prep if possible to prevent rotation. Or slip. I run my controls and brakes at a torque where a big hit would just rotate the mounts, but pressing the lever would never rotate them. This is always a pretty low torque spec.

 

All of Seths pictures indicate evidence of over tightening at some point in the life of the bars. Even if they weren’t at this point at the time of the crash. We have all tightened and then backed off something in our history of tightening parts.

 

Pair this with a few high stress hits on the bars. (I’m curious which puts more stress on the bar. Blowing through suspension from a drop and your body weight flexing the bar, OR the bike free falling and flipping in a wreck. My gut tells me the former pits higher stress because of the inertia.)

 

I run carbon bars on all of my bikes. I keep an eye on them as well. There is one that is due for a replacement after som big crashes and dings, but that’s on my road training bike. I should probably place an order...

 

 

Sent from my iPhone using Tapatalk

[RidingAgain]

22 minutes ago, TheX said:

Why didn't you talk about it in this thread?

It seems that when I was writing my OP for the thread I started, this one was started — or maybe I just missed this one. I started to create my thread and then had to go do something and came back maybe an hour or so later and just finished it. Then after submitting it I saw that there was this thread on carbon bars.

[Kyle]

I put carbon bars on my single speed to test out the comfort thing, and I don't really get it.  I notice that they're more flexy but it doesn't translate into comfort for me.  The carbon seat post is great though.

Carbon bars probably break at a lever clamp because the clamp prohibits the bar from deflecting naturally and concentrates stress.  I don't think it's necessarily a sign of over tightening.

 

[JRA]

I've had carbon Renthal Fat Bars on my Mach 6 for 2 plus years with no issues. I wipe them clean and check them regularly. Granted I don't pound them like Seth but I haven't exactly been nice to them either.

[Seths Pool]

I will also mention, to fair- that in the beginning or World Cup is a nasty rock garden, into an open area, then two nasty sections of rocks and the last one has a 90 degree left turn immediately after smashing down and through a section of rocks. 

On this run, I was definitely pushing the bike really hard, a 160/160 trail bike and I would say I was treating it more like a DH bike.

on the rock section into 90degree turn, I cornered really hard and tons of weight on the front wheel to the point where I almost collapsed my chest into the stem. Borderline crash turn status but I kept control of the bike and held it. I didn’t hear and noises but i know for sure it was probably maximum body pressure possible into handlebar without crashing. I’m about 210 before gear. If anything fatigued it on that ride, it was that. 

.....buuttt STILLLLLLLLL!!! Cmon!

[Bamwa]

So are your levers loose enough to spin is the question.

[Seths Pool]

5 hours ago, Bamwa said:

So are your levers loose enough to spin is the question.

no, I cranked the clamp screws down as tight as my hands could turn them and then I used an old seat post as a cheater bar to really get them tightened down.... 

[Chief]

Carbon paste definitely helps. It allows you to get enough torque without slipping or over tightening. Something else to consider is how sharp the edges of whatever you clamp to your bars is. The sharp edges of clamps can damage the carbon in ways you can't see.

[Seths Pool]

6 minutes ago, Chief said:

Carbon paste definitely helps. It allows you to get enough torque without slipping or over tightening. Something else to consider is how sharp the edges of whatever you clamp to your bars is. The sharp edges of clamps can damage the carbon in ways you can't see.

I think im just gonna stick with aluminum from now on and not have to worry about a bunch of potential tiny oversights that may directly result in my serious bodily injury or death. 🙂 

[JRA]

3 minutes ago, Seths Pool said:

I think im just gonna stick with aluminum from now on and not have to worry about a bunch of potential tiny oversights that may directly result in my serious bodily injury or death. 🙂 

i'm not going to run out and buy them today but my next hb purchase will probably be aluminum.

[Kyle]

Have you considered tungsten or depleted uranium?

[JRA]

4 minutes ago, Kyle said:

Have you considered tungsten or depleted uranium?

I'm waiting for S&M Bikes to jump into the mtb market and start making 4Q baked chromoly 31.8 riser bars with a lifetime warranty.

[Anita Handle]

For those seeking vibration dampening, have you considered the Spank Vibrocore? They're aluminium with a dampening foam injected into them. Probably my next handlebar purchase.

https://www.pinkbike.com/news/spank-spike-800-race-vibrocore-handlebar-review-2014.html

 

[JRA]

10 minutes ago, Anita Handle said:

For those seeking vibration dampening, have you considered the Spank Vibrocore? They're aluminium with a dampening foam injected into them. Probably my next handlebar purchase.

https://www.pinkbike.com/news/spank-spike-800-race-vibrocore-handlebar-review-2014.html

 

crossing over from the I'm so ghetto thread

[throet]

1 hour ago, Anita Handle said:

For those seeking vibration dampening, have you considered the Spank Vibrocore? They're aluminium with a dampening foam injected into them. Probably my next handlebar purchase.

https://www.pinkbike.com/news/spank-spike-800-race-vibrocore-handlebar-review-2014.html

 

Definitely something to consider. Also I've looked at the Revolution Grips but can't bring myself to spend $90 for them. 

[RidingAgain]

Came across this...

(Not sure what happened... But if you click the FB logo at the top right corner it will open a tab to the person's comment).
 

 

Edited September 5, 2018 by RidingAgain

[ATXZJ]

I would imagine carbon bars have come a long way in over a decade. 

[TheX]

1 hour ago, ATXZJ said:

I would imagine carbon bars have come a long way in over a decade. 

They have for sure. I spent a lot of time around fighter jets, and composites. When a part was even suspected of any impact or damage it was tossed. We buy and sell used carbon bits all the time, and most of the time it's fine...until it isn't.