Carbon Seatpost question - integrity issue ??



Adam-from-SLO

New Member
Nov 30, 2003
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Hello,

I have noticed on certain Carbon Fiber seatposts(for ex. a Campy REcord carbon, I won a Ebay auction over a year ago.... and the guy sent it to me... and the back part of the post- possibly where it was clamped onto the frame- left a stress-crack / or compression crack at some point in time). Actually, on the back part of the post, there was a small 1mm X 7mm - long chunk- actual Carbon missing from the post . I sent the post back, for my money back. I told the seller that its a safety issue with me, thats why I sent it back. Could this carbon post have been used... with no issues ????

I know, many of you will say... "when carbon goes, it goes /catostrophic faliure" . I already know this. Sure, there is some stress being applied to a seatpost when a rider is riding..... but how would a seatpost hold up with this situation over time ??

Thanks in advance.
 
Adam-from-SLO said:
Hello,

I have noticed on certain Carbon Fiber seatposts(for ex. a Campy REcord carbon, I won a Ebay auction over a year ago.... and the guy sent it to me... and the back part of the post- possibly where it was clamped onto the frame- left a stress-crack / or compression crack at some point in time). Actually, on the back part of the post, there was a small 1mm X 7mm - long chunk- actual Carbon missing from the post . I sent the post back, for my money back. I told the seller that its a safety issue with me, thats why I sent it back. Could this carbon post have been used... with no issues ????

I know, many of you will say... "when carbon goes, it goes /catostrophic faliure" . I already know this. Sure, there is some stress being applied to a seatpost when a rider is riding..... but how would a seatpost hold up with this situation over time ??

Thanks in advance.
Sounds like more than just a light scratch, so I'd guess the post was weakened in the area of most bending stress. When or if it would have failed on you is impossible to say. Would depend on your weight, what type of holes and bumps you hit, as well as how you mount the post and seat on your bike. (IE, if you mount the post lower so the damage is inside the frame and below the clamp, that may be OK).

But certainly think you did the right thing in shipping it back. Hope the seller refunded your money and then threw the post in the trash rather than reselling it.
 
The previous owner probably used the post with the wrong type of clamp, or the clamp installed incorrectly. It might have worked, but the aftermath of a seatpost failure is usually pretty messy. It's really not something that's worth taking chances with.
 
artmichalek said:
The previous owner probably used the post with the wrong type of clamp, or the clamp installed incorrectly. It might have worked, but the aftermath of a seatpost failure is usually pretty messy. It's really not something that's worth taking chances with.

Thanks for all the great responses.... duely noted !

How about a small scratch 2-inches long, to the outside of a seatpost, maybe 1/2 mm deep ........ whould this be cause for concern ?
 
Adam-from-SLO said:
Thanks for all the great responses.... duely noted !

How about a small scratch 2-inches long, to the outside of a seatpost, maybe 1/2 mm deep ........ whould this be cause for concern ?
If it's only 0.020" deep, and no CF material is exposed, would say it's only in the topcoat and not a worry at all. Art may have a different view.

Your concerns point up a fact of life with CF posts, handlebars and steertubes. They can be very strong in terms of carrying the load, but must be fitted carefully and clamped with the right hardware and proper torques to avoid damage.
 
dhk said:
If it's only 0.020" deep, and no CF material is exposed, would say it's only in the topcoat and not a worry at all. Art may have a different view.
No, I would have to agree. If it's just a clear coat scratch, and you're sure it's a scratch rather than a crack it's not a problem.