MTB CF Seatpost

[Gooby]

I am looking to replace my thompson seat post with a carbon Fibre model. Only problem is which one? Needs to be 27.2 diameter. Anyone with experience?

[shouldbworking]

Gooby said:

I am looking to replace my thompson seat post with a carbon Fibre model. Only problem is which one? Needs to be 27.2 diameter. Anyone with experience?

http://lmgtfy.com/?q=removing+stuck+carbon+seatpost

[dubbs]

Mate of mine had his CF post snap on his Scott.... could have been VERY painful!!

[h4muf]

Why would you swap a Thompson for owt else??

I've had a raceface CF post fail on me on my cross bike.Straight back to alloy.

Make sure it's a two bolt head fixing on whatever you buy!

[oddman]

Don't

I snapped a carbon seat post on a road bike.

Must be easier on a mountain bike

[neilski]

It'll only end in tears....









Well, watery eyes at the very least.

[dubbs]

That's one gash you'll never want near your old chap!!!

[Clio200pat]

I'd stick to an ali seatpost. I actually changed the carbon one that came on my road bike as I didn't want to run the risk of it snapping.

[SixtySpeedTwin]

I have spent plenty of years designing stuff in CF and i have an ally seat post
CF very rarely has a ductile failure and i have pulled shards of the stuff out of my hands plenty of times so wouldn't want to do that out of my ugly bits!
It can be done but it's difficult to make one post layup fit all uses / riders weight and various post lengths for a commercial product.

Cheers
Clive

[Ironballs]

I have a Ritchey post that has been very reliable, however it scuffs to buggery when you raise and lower it, the polished alloy corroded and the steel fixings all rusted. Not what you want with a 100 quid post. I'll be replacing it with a dropper post at some point

[BOR]

Syntace P6 Carbon on my Cube. Four years old, zero problems, but.....

it's 34,9mm diameter, and at that size, a tube made from cardboard would probably be ok.

[CC07 PEU]

What about carbon fibre handlebars? Surely it'd be worse if these snapped on you - especially on a downhill section?

I recently installed a set on my mountain bike...

[Gooby]

The reason for it is the usual one - weight. I am looking at component by component and just trying to minimise the weight. I have been using CF handlebars for years with no problems, why do seat posts break and not bars?

[anonymous-user]

I think generally bars have flexibility to twist/bend in different directions independently at both ends and have less clamped area, also in MTB terms the post takes much more % of rider weight than on the road.

I'd also guess a post would mainly take compression and flex in one direction all the time with a fixed length and clamping point more continuously than on a road bike.

ie. you hit a bump and the compression is your probably near enough your full weight and momentum down and backwards on your post. If the clamp is too tight and/or the saddle position accentuates and forces or creates weak points I could imagine that your light weight post won't last long.

[rhinochopig]

If you want to save weight WRT seat posts, one option - one that I took - is to fit an SDG I-Beam saddle and seat post as together they save a good few hundred grams over a traditional post and saddle.

I've run them on Tandem MTBs, MTBs (Hardtail, and full sus) and on my road bike with only one issue due to a manufacturing fault- the tube started to crack. I would avoid CF tubes and bars purely because of their failure mode.

[Beyond Rational]

I've just stopped using the I-Beam due to another instance of a "manufacturing fault" in a new post after 2 rides. But then there is always the reassurance of that 30 day warranty .

In the price range of an I-beam saddle and alloy seatpost combo, I can't see where you'd get a good few hundred grams in weight savings. In the larger (30.9/31.6 etc.) sizes, when comparing 400mm posts, there are only a few grams in it between the Thomson Elite and SDG offerings. The railed saddles weigh more, but IMHO the weight is rightfully there - I've used carbon and alloy I-Beams with Bel Air ST and SLs and they are much harsher than traditional rails. Now I've swapped to a Thomson and Charge Spoon, I don't know why I hung on to the SDG for so long. I'm now kind of glad I had a seatpost fail and lost faith in them.

Edited by Beyond Rational on Monday 15th August 14:24

[Gooby]

I looked at I beam but that means I will have to get a new saddle and my Gobi is VERY comfy and very expensive...

My riding buddy has had a CF (race face) post for 2 years with no problems. I was looking at a crank bros "11" post....
The reason for the curiosity was I had to stick the post in and I found it very light in comparison. I also find CF far more comfy to live with (handlebars).

Anyone make a Titanium / CF composite 'post?