|Becoming impaled on a carbon seatpost?||JD88|
Dec 2, 2002 9:38 PM
|Has anyone ever heard of or known anyone whose carbon seatpost broke on them whilst riding? I was just reading a review where the poster mentioned that he read about a guys carbon post snapping and impaling him through the leg and nether regions (read reviews on the 2002 Giant TCR2). Apparently he was lucky to survive the blood loss. This may have permanently put me off carbon posts...|
Dec 2, 2002 10:28 PM
|I don't know, sounds suspicious. If I was unfortunate enough to have a severed seat post go through my leg I certainly wouldn't sit back down on my nether regions! The morale of the legend is to avoid counting grams for the seat, seatpost, pedals, stem, and bars.|
|re: Becoming impaled on a carbon seatpost?||JohnIV|
Dec 3, 2002 5:03 AM
|Saw a guy break a carbon Alien post at a race. He was smart enough not to try and sit down after it broke. Still spooky seeing a shattered seat post, though.|
|re: Becoming impaled on a carbon seatpost?||geeker|
Dec 3, 2002 5:09 AM
|I think this (impalement; don't know the injury specifics) really happened to a (European?) triathlete. He was badly hurt, but returned to competition after a long layoff. I read race coverage mentioning his return on a reputable website. Unfortunately I forget which site...|
Dec 3, 2002 7:35 AM
|I remember reading about a racer whose carbon seat post broke during the time trial at the 2000 Olympics in Sydney. He was injured pretty severely. I don't recall any more details, but it happened.|
Dec 3, 2002 7:43 AM
|I googled and found some links re. the (famous) triathlete. He medaled in the Sydney triathlon and got injured while subsequently training:
[The May '02 entry]
|I guess it did happen||laffeaux|
Dec 3, 2002 11:28 AM
|Althoughg it really did happen (according to teh articles), the seat post bolt broke, not the post itself. There's no reason to think that the broken bolt had anything to do with the fact that the post was carbon. A similar injury would have occurred with an aluminum post.|
Dec 3, 2002 11:35 AM
I googled and found some links re. the (famous) triathlete. He medaled in the Sydney triathlon and got injured while subsequently training:
[The May '02 entry]"
I read both those links, and they don't mention anything about the seatpost being made of carbon. Also, they refer to a bolt breaking being the cause of the seatpost accident:
"On February 3, while training near Sydney for his first Ironman at Forster, a bolt snapped on Rehula's seat post and the jagged end was impaled in his rectum in a horrifying 25 mph crash."
Carbon Fiber, if made correctly, should be one of the strongest materials in the world. It was originally combined with Titanium in the construction high-G military fighter planes, and is now the material of choice for America's Cup yachts, among other high-load-bearing machines:
"He thinks of the [America's Cup yacht's] hull as a narrow bridge with supports at each extremity and with a 50 tonne truck parked in the middle. "When you consider that the bridge, or in this instance the hull of the yacht, only weighs about a tonne, an awful lot is being asked of it." And thats not all. As a kind of diabolical practical joke, a 20 tonne lump of lead - the keel - is suspended directly under the imaginary truck.
Most components on an America's Cup yacht are made of carbon fibre [including hull, keel strut, and mast], which combines excellent strength properties with light weight."
Personally, I'm not too worried about the strength of carbon fiber seat posts.
Dec 3, 2002 5:53 AM
|Until I see evidence of this happening, I'm considering it
an urban legend.
Maybe the snopes urban legend website should be alerted and
they can track down the facts.
I've heard about this time and time again and no facts that
support it so far.
|re: Becoming impaled on a carbon seatpost?||JimP|
Dec 3, 2002 8:31 AM
|I was almost impaled on an aluminum seatpost when the seat binder bolt broke and the seat came off. That hasn't really set me against aluminum seatposts since it could happen with any post.
The major issue that I see with carbon seatposts is whether the bike frame and binder mechanism is designed to hold a carbon post. Most of the designs for seatpost binding were designed for steel seatposts but work well with aluminum or titanium seatposts. A carbon seatpost is quite soft on the surface compared with other materials and will dent when used with an internal wedge type binder like Look uses. The risk is tightening the wedge too tight which can crush the epoxy and crack the carbon fibers. Other manufacturers use collers that can pinch a small area where the tube exits the frame causing problems.
The USE Alien posts come in only 2 sizes - 25.0 & 27.2 but come with shims to fit other sizes. USE recommends using the 27.2 shim with the 25.0 post for a 27.2 bike since the shim is designed to spread the load and stress over a larger area.
|re: Becoming impaled on a carbon seatpost?||scottfromcali|
Dec 3, 2002 8:44 AM
|I have that exact bike with the imfamous carbon post. I wiegh 200 and have never had a problem.|
|re: Becoming impaled on a carbon seatpost?||Lactate Junkie|
Dec 3, 2002 11:54 AM
|Light stuff breaks. Even heavy stuff breaks. If you ride light stuff you should watch it more carefully. Chances are the post had shown signs of breaking for a long time before it acutally did and the guy either didn't notice it or chose to ignore it.|
|re: Becoming impaled on a carbon seatpost?||JimP|
Dec 3, 2002 12:52 PM
|I had a couple of Easton carbon seatposts prior to the USE. I called the Easton rep about the dents I was putting in the epoxy surface of the seatpost with the wedge type binder. He asked if there were any white lines comming out from the dents. He explained that the dents in the surface epoxy was no problem but the white lines would indicate stress fractures in the carbon fibers. Since my bike, fork, seatpost, & wheels are all carbon fibre, I look carefully for stress risers.