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What are the advantages of a carbon seat post?(20 posts)

What are the advantages of a carbon seat post?Ambishawn
Jan 1, 2003 11:23 AM
I'm thinking about installing a carbon seat post in My steel IF Crown Jewel. Need to be 26.8mm dia. I realize this size somewhat limits My seat post choices in general. I weigh 193lbs.
mainly weightDougSloan
Jan 1, 2003 12:23 PM
1. lighter
2. cannot rust or seize
3. damps vibration slightly compared to metal
4. looks cool(?)

You can get the same heads on carbon or metal, so basically, it's just a tube where the difference is.

Doug
Sorry to inform you doug, but..pa rider
Jan 1, 2003 3:52 PM
you can seize a carbon seatpost. My LBS told me this summer to put a light coat of grease on my carbon seatpost. I ride a cannondale (aluminum). He said the post can seize because he had one do this on him.

Apparently he had a customer do this to one carbon seatpost. The guy must never moved his seatpost and rode in the rain a lot. I wasn't there to see this problem, just mention the point.

This point everybody says about never put grease on carbon post is bull. I had aluminum post slip by putting grease on it with a plastic shim (use suspension post). Wiped the grease off it worked ok, but there still grease on the post. I do the same with a carbon post as I did with the USE post.

Just making a point no arguement Doug.

Emory
but how?DougSloan
Jan 1, 2003 5:45 PM
I'll accept they can get sort of stuck (as it obviously has happened), but they cannot rust, corrode, or gall, right?

Kestrel recommends grease, too, BTW.

Doug
but how?pa rider
Jan 2, 2003 3:01 AM
Not sure about what your calling gall, but I dought that's the case. I had water trapped on my post when I pull it out after getting caught in the rain.

The only comment the lbs made was the two materials can bond together. I'm not an engineer either, so i didn't question his comment.

Doesn't water trapped in bottom bracket do something to the aluminum shell? I think LBS comment was carbon can form to aluminum, but not according to our understanding of corrosin or oxidation. I'm paying over $100 for an easton post for my new bike. I'm putting a light coat of grease on it to make sure I don't screw it up.

Emory
pa rider is correct on this onemotta
Jan 2, 2003 6:00 AM
Aluminum and carbon are at different points on the Galvanic scale and when joined with an electrolyte,( sea water, salt water, sweat) galvanic corrosion can occur on the less noble of the materials.
Doug is right in this casespookyload
Jan 1, 2003 11:03 PM
There is no physical way for a carbon post that is non-metalic to gall to a steel or aluminum frame. I am not an engineer, but in order to gall, the two surfaces have to be dis-similar metals. Even if you call the carbon an element that COULD gall to metal(which it can't since it isn't a metal), there is a clear coat over carbon posts to prevent that from happening. And I do know for a fact that clear coat can not gall to anything. The worst you should get in a carbon post is maybe the clearcoat rebonding to the inner surface, but that would take extreme temperatures to resoften polyeurothane. Having worked in a bike shop I know that urban legends run rampant.

As for the origional post, you will be fine on any carbon post at 193 lbs. I am 185 and ride a USE alien carbon with no problems. I also opted not to use the shim, so I have a 27.2 in my 27.2 frame. The shim might work for you though, because the 25.0 Alien seatpost is very common, and the shim for 26.8 is also very easy to find. Could be an easy fix for you frame size. If you decide on an Alien, you can save big buck at www.labicicletta.com I got mine from them for ~$89.
galling can occur with similar materials, in paticular, sst (nm)maximum15
Jan 2, 2003 9:28 AM
Trek says no grease on seatpostsChen2
Jan 2, 2003 9:36 AM
if used in an OCLV frame. I know this is a bit off topic but since we're talking about greasing seat posts and there are a lot of OCLV's out there I thought I should offer the info.
re: What are the advantages of a carbon seat post?gtx
Jan 1, 2003 1:13 PM
unless you have a lot of exposed seatpost I don't think you'll get much out of it in terms of ride quality. At your weight you might have problems with it in terms of reliability. Have you checked the Thomson posts? You see 'em on a lot of IFs (they come in 26.8). Light and bulletproof.
re: What are the advantages of a carbon seat post?pa rider
Jan 2, 2003 3:21 AM
I got the ergo look seat post. The advantage I got was a better setback postion and tilt adjustability.

I felt the carbon post took a lot of the road vibration buzz out. This just tune the feel a lot better than the aluminum seatpost I had on the cannondale bike. I never rode a thompson seatpost, because they don't have enough setback for me, so I can't compare to it like all the others on this board mention.

The best seatpost I evered use was a sycro's and it wouldn't work for me on this bike. I'm 185 lbs and the ergo look seatpost hasn't develop any problems for me. My buddy rides a record carbon and his creaks a lot. I have heard good and bad about the campagnolo carbon post, so I decided on the Look post.

A lot of the customize bikes (get what parts you want on your new bike) people buy are having carbon post here in harrisburg pa. I think the lbs make more money and try to steer you think it will ride like titanium.

I felt it was worth a try using a carbon seatpost, because before I got a full suspension mtb I had a suspension seatpost. Trying a different seat post material gave my bike a different ride feel. It's hard to explain unless you test both seatpost on the same day with the same bike and seat.

Just my 2 cents.

Emory
Strictly personal preference,Leroy
Jan 2, 2003 7:07 AM
in my opinion. I have a carbon, steel and an al. post in different bikes and I cannot tell the difference when riding. If weight is a big deal with you, go with carbon; if cache matters, pick the brand name for you; if appearance is the thing, go with the best looking. I can switch them around bike to bike and I swear there is zero difference in performance. When they're dialed in and hold the saddle in the right place, that's all you need.
A caution about carbon seatpostsJimP
Jan 2, 2003 1:30 PM
A caution about carbon seatposts. If your frame uses an internal wedge type binder, like Look and Aegis, the surface of the carbon seatpost is soft and will dent. The dents are not a problem by themselves but if you continue to tighten can crush the carbon fibres. I dented 2 - 26.8mm Easton seatposts. I have changed to a USE 25.0 with 26.8 shim. The shim has an aluminum shell that is hard and spreads the wedge force over a large area on the seatpost.

Jim
Carbon dampens better than aluminum....nmREPO42
Jan 2, 2003 11:52 PM
Hummmmmmmmcurlybike
Jan 3, 2003 7:33 AM
Wouldn't that be damps vibration, when you dampen something, you make it wetter and most frames get too much water inside already. Just a thought.
dictionary has it both ways nowDougSloan
Jan 3, 2003 7:54 AM
Main Entry: damp·en
Pronunciation: 'dam-p&n
Function: verb
Inflected Form(s): damp·ened; damp·en·ing /'damp-ni[ng], 'dam-p&-/
Date: 1547
transitive senses
1 : to check or diminish the activity or vigor of : DEADEN
2 : to make damp
3 : DAMP 1c
intransitive senses
1 : to become damp
2 : to become deadened or depressed
- damp·en·er /-n&r/ noun

Main Entry: 2damp
Date: 14th century
transitive senses
1 a : to affect with or as if with a noxious gas : CHOKE b : to diminish the activity or intensity of c : to check the vibration or oscillation of (as a string or voltage)
2 : DAMPEN
intransitive senses : to diminish progressively in vibration or oscillation


http://www.m-w.com/cgi-bin/dictionary
alsoDougSloan
Jan 3, 2003 7:57 AM
The word "dampen" has 7 different senses:

Verb: change: Smother or suppress.
change: Make moist.
perception: Deaden (a sound or noise), esp. by wrapping.
change: Reduce the amplitude (of oscillations or waves).
change: Make vague or obscure or make (an image) less visible.
change: Check. Keep in check (a fire).
change: Lessen in force or effect.

http://www.hyperdic.net/dic/d/dampen.shtml
thanxcurlybike
Jan 3, 2003 5:38 PM
I appreciate your work in helping me to improve my vocabulary. It should be clear that my mental dictionary was (way) out of date.
since you brought it up, I thought you would be interested nmDougSloan
Jan 3, 2003 6:22 PM
Serves me rite fer b'n a smart ass n/mcurlybike
Jan 3, 2003 7:27 PM