Carbon vs Alloy Seatpost, much difference?

As in title really. I've heard carbon may be more comfortable and a bit lighter. But is it all that special?
Discuss.

James x

Heavy carbon weighs more than light alu.

The diameter affects the flex and perceived 'comfort'.

Budget often dictates which material you go for.

Weightwise It depends what alu seat post you are comparing it to, having seen a couple of MTB carbon posts snap at races it is one area I am very hesitant to put carbon on my MTB as I have quite a lot of post showing, which will out extra strain on it at the clamp area.

Three carbon things to avoid would be seat post, bars and steerer tube, any of those three snap and you'll know about it. A Thompson Master piece would be a good choice.

I've got all 3 of those, and I've not died.

Weirdly, alu bars/seatposts/steerers are able to break too.

Carbon bars are probably the most commonly used carbon part, after headset spacers!

I've got a Ti seatpost which is very comfortable and a bit more 'twangy' than the Alu posts I've used.

ive seen alloy posts snap at races ive done too …

im with nick ….

running a ritchey wcs carbonpro post – and a raceface next SL and a giant carbon Aero pin on my bikes …

wouldnt dream of running cheap carbon – all the snapped carbon posts ive seen have either been cheap or over tightened or both – neither are a good reason not to buy a good quality carbon post and look after it !

what about frames ? if that snaps youll know about it ….

still got a carbon frame here

yea, but ti costs an effin' fortune!

I've broken 2 aluminium (one EA70, one cheep) posts, should I stick to a solid steel bar to be on the safe side? Having dished out untold abuse on carbon components for my degree, I'm more scared of aluminium bits snapping!

ok maybe i should explain more. its for a road bike 😳 (shameful i know)
This is the carbon one.
This[/url]is the stock on on my bike.
I had thought about a thompson but had heard things about carbon. Which do you reckon will be better?

James

Don't get me wrong I've seen alu ones go as well and I run a carbon post on my road bike, but something inside me just doesn't trust carbon posts with a long extension on an MTB.

On the road where you're incredibly unlikely to land on it hard and (unless you've got a very compact frame) there's not much sticking out of the frame you'll be fine. Carbon is able to absorb high-frequency vibrations, arguably making it more suited to road use than alu.

I'd personally go for something lighter than the Syncros, which is a tough MTB one. I use a USE Alien on the road, and have done for about 7 years.

I'd agree with Njee, the USE Aliens are nice (as are all USE posts) just understand how the clamp works before going at it with an allen key!

and unless you wish to negate having to use a seat clamp (for weight saving) then get some carbon paste – its never pleasent telling folk their thousand pound frame has bonded to there seat post – esp when they want to drop it quarter of an inch 😉

As far as comfort goes, maybe my a**e needs calibrated but I can't tell any difference at all between my cheap FSA 27.2 ally post, my Raceface Next 27.2 carbon post, or my Gravity Dropper. Maybe there's a difference I can't feel though but to hear some people talk it's a huge night and day difference, not at all convinced. Same with bars for that matter.

http://www.lhthomson.com/carbon_seatpost.htm

got a shock for you – you cant cnc carbon

thus thomson would require heavy investment in tooling

thus its easier to put a page on your website listing all the problems with none of the benifits !

He he..

Ti every time. Carbon 2nd and then aluminium 3rd as its way too uncomfortable!

The only bits of carbon I've ever seen break were both seatposts. One was a USE, the other was a cheap FSA one. Make of that what you will. Doesn't stop me from using one though. But agree with njee20, dimension more important than material

nickc – what happened when they broke? Did anyone die?

I've got a carbon one on my Roadie and alloy ones on my MTB's.

I've seen 2 el cheapo alloy ones bend most triumphantly on my mates bikes, therefor I'd never use a cheap alloy post on a bike, ever.

the carbon entered their bloodstream and went to their heart !

I've got a carbon Speccy Pave seatpost on the road bike.
It hasn't snapped and I don't have RSI in my nethers so I guess it works.

Nah, nothing so dramatic, I'm trying to remember which one broke at clamp.., the USE I think, where the carbon post was bonded to the clamp. and the FSA was probably just badly made as it just snapped as the rider sat on it. Just XC stuff, nothing full on

on this whole carbon snapping thing, can someone actually post up an image of a snapped carbon post with loads of jagged edges showing? I still don't believe that this is the way carbon fails.

http://www.bustedcarbon.com/

http://www.pardo.net/bike/pic/fail-001/000.html

First watch thisYouTube vid of a Niner carbon fork being bashed with a hammer, then read about the same bashed up fork[/url] passing the CEN test.

If carbon is used properly it will be just as impact resistant as common alloys used in bike construction.

I had a carbon seatpost once and it got scratched all to hell whenever I raised and lowered my saddle. Never got another one.

Agreed it's a slightly daft choice if you insist on putting your seatpost up and down, but one would hope that that's not necessary on a road bike!

I've seen a few carbon posts fail over the years, in most ways, from clamps coming unbonded to full on snapping leaving jagged shards. I've seen plenty of alu posts break too!

http://www.bikeradar.com/forum/viewtopic.php?t=12534958

http://aluminium.matter.org.uk/content/html/eng/default.asp?catid=89&pageid=2144417038

I notice a huge difference with my carbon seatpost. It doesn't vibrate like mad when going across dried mud fields, certainly takes the sting out.

My carbon bars have saved my wrist too, I don't get bad pains, as it doesn't vibrate as much either.

So we can conclude that stuff breaks sometimes, irrelevent of material?