VAG Driver

I've just been reading a bunch of stories about CF handlebars and seatposts and how dangerous they are. I don't believe that to be true or people wouldn't be buying them, but maybe you guys can clear that up for me?

womble

And how would yet another thread with stories about the danger or safely of CF parts help clear anything up?

Some people think CF is perfectly safe (the very experienced owner of my LBS, for example rides CF). I won't touch it again after my CF bar ends shattered and left shards embedded in my hands. Your milage may vary.

wheelhot

well, if you want to know about carbon fibre seatpost, you can check on lhthomson.com, search around and they got tell about why they dont want to make carbon fibre seatpost. The explaination is quite good. And for carbon seatpost, Easton EC90 has quite a good point about why their seatpost is better then others and I trust easton components, I own a archer equipment and I use easton carbon arrows, very straight.

DevilsGT2

It might give you weight-weenieitis.

wheelhot

welcome to WEIGHT WEENIES, INC, where we sell weenie hot dog. haha

Wheelchairman

I've got a friend who got a CF setpost embedded in his butt cheek once. I love the material and its properties, yet i'd always use an aluminum seatpost. At least if its pushed past its limits it only bends.......rather then shatter in yo'all arse

vw addict

CF is okay for mtn bars as long as you replace them every 2ish years or after a good crash. CF seatposts belong on road bikes.

LowCel 

Pretty much same as what I was thinking.

apclassic9

Just about every race I've been to where a rider comes in standing up, it's the carbon seat post that has broken. That being said, I would suppose the relative safety depends upon your weight & riding style.

ghettocruiser

Will everyone please stop saying that aluminum and thin-wall steel always bend and not break.

They DO break, and suddenly. I've hit the ground several times for this reason.

santiago

I suppose an accurate statement is that aluminum and steel will bend before they break, giving you a warning of sorts. CF has a higher yield threshold but will break rather than bend.

Curtis_Elwood

Aluminum will shear off with the best of them. It doesn't have to give you warning. Thompson's argument is that their ovalized seatposts are engineered to bend significantly before they break. I think most peoples' fear with CF is that it splinters when it breaks and turns into more of a spear instead of being somewhat blunt like aluminum.

My bike came with a CF seatpost. I don't mind it. When it gets replaced, it'll probably be with a Thompson, though. Not as much for the safety reasons, but for the fact that the Thompson actually weighs less. This is something to keep an eye on. Low-end and even mid-grade carbon components are not always lighter than their metal counterparts.

I trust carbon/kevlar for my whitewater helmet which hits rocks harder and much more frequently than my bike helmet. I also have a carbon fiber paddle. I do find it interesting that CF handlebars are half the diameter of my paddle shaft they they probably see more stress.

It's really your call. One thing that will help with the longevity of CF is to keep it protected from UV rays. 303 is a great product for this.

ranger5oh

Can someone explain to me how a broken aluminum tube is BLUNT? No way.

CF is more vulnerable to imperfections than Al or Steel. Which is probably why people think that CF always catastophically fails. With a small crack or scrape in the wrong spot, your CF bars may fail violently... and while the same holds true for other materials, it generally takes a more significant imperfection.

Curtis_Elwood

I said somewhat blunt. By comparison, aluminum more often breaks in a straight manner than CF. CF components are often manufactured with a diagonal weave. They're more likely to break in a spiral pattern for this reason. The ends of the individual fibers are very small and stiff, making them great for puncturing your tissue. I don't have any good pics of broken carbon components and can't take any pics b/c my camera's crapped out, but I have a nice example in my basement of a paddle-turned spear made of carbon and s-glass. It would totally suck, but I'd much rather hit a broken aluminum seatpost with my ass than carbon.


https://www-gt.diff.net/media/2000_09....thumbnail.jpg

https://www-gt.diff.net/media/2000_09....thumbnail.jpg

junkyard

Keep in mind that information on these sites is for marketing purposes as well as informational purposes. They want you to buy their product, so they are certainly going to be stressing the positives.

stapfam

I used to be a fibre glass laminator and I will not use C.F. on anything. Fibre glass is a good material- It is lightweight- offers some protection against track harshness as it will flex, and will last a lifetime.

And it will last a lifetime if it is not overstressed, does not receive any sharp knocks and is made properly for the use it is intended. Unfortunately- It can be overstressed by overtightening a bolt. It can fracture internally from any sharp knock leading to a failure at a later date, and although a good named product I would expect to be made properly- There are a lot of "FAR" too cheap products on the market.

Now if you are a weight weanie and must have the lightest stuff around- then get it. But when you have a knock on the material- change it before you ride again.

IAMTB

Here's the Thompson link for ya: https://www.lhthomson.com/carbon_seatpost.htm

Pheard

An interesting thread on mtbr, about someone who has had quite a few misfortunes with cf frames.

https://forums.mtbr.com/showthread.php?t=244081

euroford

especially the seatpost, but overall i don't think carbon has much of a place on mountain bikes at all.

having read thompsons article re: carbon posts, i think they make a pretty logical argument.

maximan1

Carbon fiber is not made to withstand or absorb shocks. I would be afraid to put any carbon stuff on my MTB

Curtis_Elwood

So then why are nearly all high-impact helmets made of carbon fiber?

maximan1

Cause people are dumb

a2psyklnut

Weight and the fact that they say to dispose of after significant impact. Basically a very expensive one hit wonder.

born2bahick

Ahhhhh, Wonder how many carbon bikes, bars, and seatposts are out there that you don't hear about because they didn't fail? I Tend to run towards new technology, Mankind as a whole tends to avoid change. We went through these same arguments with V brakes over cantilevers, aluminum frames over steel, disc brakes over v brakes, index shifting over friction, so on and so on......... we have two men in town this year that broke aluminum frames. Quick abrubt clean breaks. Thankfully no one was hurt! I can only go by my experiences. I think Womble was right, we can chew this thing to death again, but it won't change anything.

maximan1

The fact that people get carbon fiber stuck in the ass cause their seat posts break. (From this forum)