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Alloy seat post with carbon frame???

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Alloy seat post with carbon frame???

Old 09-21-11, 08:08 PM
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GMM
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Alloy seat post with carbon frame???

Can you use an aluminum seat post with a carbon bike?

Last edited by GMM; 09-22-11 at 12:10 PM.
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Old 09-21-11, 08:23 PM
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all combinations of frame material and seatpost are ok
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Old 09-21-11, 09:38 PM
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More specific
7000 series aluminum is an alloy containing Zinc,[old dry cell batteries are C & Zn]
that may not go so well
but 6000, and 5000 should be OK.
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Old 09-21-11, 10:09 PM
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Originally Posted by GMM View Post
The seat stays, the way they're positioned lower then the top tube, sure seems to indicate that the whole seat tube flexes while riding. Just wondering if using a stiffer, non-carbon, seat post would adversely affect the carbon seat tube in any way. A friend may purchase the frameset, without carbon seat post, and thinks he should only use a carbon post rather then aluminum.
Flex? Like a spring or something? Definitely not the case. That frame is meant to be rigid, and I'm sure it is. Some older steel/Al bikes had seat stays that came in lower like that. They didn't flex.

Your friend can afford a full carbon bike. Why not just get the carbon post too?

Originally Posted by GMM View Post
Just wondering if using a stiffer, non-carbon, seat post
Neither one would flex or bend a visible amount under normal riding.
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Old 09-22-11, 08:41 AM
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Originally Posted by fietsbob View Post
More specific
7000 series aluminum is an alloy containing Zinc,[old dry cell batteries are C & Zn]
that may not go so well
but 6000, and 5000 should be OK.
Huh? What does any of this have to do with seatposts unless he thinks the seatpost will run his lights?
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Old 09-22-11, 08:45 AM
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Originally Posted by HillRider View Post
Huh? What does any of this have to do with seatposts unless he thinks the seatpost will run his lights?
Galvanic corrosion
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Old 09-22-11, 08:59 AM
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Originally Posted by demoncyclist View Post
Galvanic corrosion
Yeah, I knew what he was referring to but that specific aluminum alloy isn't any different than others in this application. Any aluminum seatpost will have a corrosion problem in any other frame material whether it's steel, aluminun, titanium or carbon. As will a carbon seatpost in any metal frame. Grease or assembly paste is needed for any and all of these.
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