Alu vs carbon seatposts - experiences?

bigpikle

So up until now I've always had carbon seatposts on my bikes but am wondering if I'm really gaining anything other than a few g's of weight saving? I need to buy another for my latest build and am wondering if I should save a lot of £££ and get alu this time? Comfort is what I'm more concerned with than weight saving - does alu make any noticeable difference in peoples experiences?

The build is my mile-munching winter build using a ti frame - hence the comfort priority. Usually I'd go straight for the Ritchey WCS carbon but at £150+ compared to the £50 for the same alu version I'm wondering this time. What, if any real-world difference to the ride does choosing alu make?

Thanks

BillyMansell

I tend to be more concerned with the properties a seat post has to offer, such as comfort, than be too concerned with the actual material as you can get comfy alu posts as well as carbon ones and the actual material doesn't always dictate the performance but rather how the material is used.

I used to use a Thomson Masterpiece but now have a Syntace P6 hiflex carbon on my road bike. Both are excellent posts for comfort which is why I bought them but neither are cheap. If you can find one that's cheap (relatively speaking) and gives you the comfort you want then go for it.

Rodders30

I had a carbon one and from undoing and doing up, eventually it cracked. Perhaps that's my fault for not using a torque wrench. Took quite a few years.

Went to get a new one, would have cost quite a bit. They had an alloy one for £10. I bought that. It wont crack, it weighs a little more. I don't notice any comfort difference. I'm no slower.

topdude

Suggest you get the alloy one and do a comparison against your Ritchey post, see if there really is a difference ?

Looking at it logically where would the "comfort" come from in a carbon post, it is a stiff material made into a stiff tube ?

Wirral_paul

topdude wrote:

Looking at it logically where would the "comfort" come from in a carbon post, it is a stiff material made into a stiff tube ?

And a pair of padded shorts is a big piece of lycra and a bit of foam - but the difference between crap shorts and top quality shorts will be like night and day to your backside after 100 miles.

There's a bit more to it than just being a "stiff tube".

BillyMansell

topdude wrote:

Looking at it logically where would the "comfort" come from in a carbon post, it is a stiff material made into a stiff tube ?

The notion that a carbon post would be stiff just because it's carbon is nonsense, it's how the post is designed and engineered from the materials used that makes the difference.

A Syntace P6 HiFlex Carbon is designed and layed up to flex up to 10mm whereas a cheap wrapped carbon post may offer no flex for comfort. Similarly, A Thomson Masterpiece is designed and machined to flex more then 5mm whereas a cheap drawn aluminium post tube with pressed in head may offer no flex for comfort.

The design and engineer of high quality posts may also utilise other properties known of each material to offer comfort through the use of the material itself, something which may not be fully considered in the manufacture of cheaper posts.

ads2k

Material will have an impact on comfort, but so will the amount of post showing.

The newer post designs by Canyon VCLS and the Syntace Hi-Flex (other's are available..) are both designed to move laterally and offer comfort by moving front to back BUT only work if enough post is showing . Long story but just a had a bike fit which moved my post UP 40mm and the difference in comfort from the above Syntace post IS very noticeable in absorbing impacts and road vibration.

So how much post will be showing ?? I'm sure you got the right size frame mate .

Also with a Ti frame and Alu you may want to consider how the different materials will act with each other... maybe Ti would be better.

PS...how's tricks mate And what frame did you go for, I was recently offered a Enigma, but decided I wanted full mounts for a winter bike which this particular one didn't have..

pitchshifter

Thomson Masterpiece is a lovely post. At 189g its not heavy either.

cadseen

Many other factors effect comfort much more than the seatpost, go for cheaper option if weight is not important.

diamonddog

pitchshifter wrote:

Thomson Masterpiece is a lovely post. At 189g its not heavy either.

^^This

Bordersroadie

pitchshifter wrote:

Thomson Masterpiece is a lovely post. At 189g its not heavy either.

My 27.2 x 240mm is only 158g.

Beautiful posts and weightweenietastic!

I'm just fitting one to a Ti new build. No worries with the different metals, it's urban myth.

philbar72

going from a easton ea30 to a 3t doric has helped significantly. A few club mates use Thomson, all reccomend them.

cycleclinic

I have a thompsen Elite which I have got down to 180g in 300mm ish length. I have Deda carbon posts. They both support me but as they are on differet bikes it is difficult to compare them directly. I feel comfortable on both but I think that is more the seat and tyre/pressures.

g00se

Another thing to consider is how much post is showing. If it's just 15cm, then it's not going to make much difference what it's made of.

Bar Shaker

If both were painted the same colour, you would never know which was which.

Seat posts are so stiff and so resistant to tubular compression that they are the one element of a bike that will do nothing to enhance the ride comfort.

bigpikle

thanks all - some good ideas.

Its a compact frame so plenty of post showing and should be able to take advantage of some flex. I use a 20mm setback usually, which the Syntace doesnt seem to offer, although a quick look at their site suggests the clamp might offer as much adjustability anyway.

Sorry, but the setback Masterpeice looks plain wrong on a road frame - the bend in the post looks fugly!

BillyMansell

Because the design the Syntace rail clamp has a short upper half it should give you about 15-20mm setback.

If you're interested in the hi flex carbon post and require a 30.9mm post or bigger (with shim) then Bike24 are selling them for £84 +p&p.

ads2k

The syntace post will give you the adjustment you need for sure (see here)

http://www.bike24.de/1.php?content=8;na ... ,4,9;mid=3

But I bet sod's law says you need a 27.2mm post ..

dennisn

FWIW my Easton carbon post cracked on me. Actually it was the clamp part. Didn't notice it until, for some reason, I took a really close look at it and there it was, a small crack that I could only envision getting bigger. So it lays in my basement and I have thoughts of getting a new clamp for it but a bunch of searching has yielded nothing yet.
So I'm using an aluminum Thomson and can't notice any difference other than it seems to NOT allow the saddle to rock like the carbon one did. This could have been due to the crack though. I'm not really a fan of one bolt posts.
Don't think they hold the saddle as well as two bolts, but that may just be me.

bigpikle

31.6 needed...

BillyMansell

Bigpikle wrote:

31.6 needed...

Get on of these shims (assuming the frame's okay with a shim) and you're sorted.

bigpikle

hmmm....not normally a fan of shims etc but a quick Google suggests no issues, and it might be a way to get the post at a real saving as well. Tempted.

Only slight issue is the post length - frame is pretty compact and I'm probably going to need close to 200mm of post showing, so on a 300mm post its going to be right on the edge of the min inserted length. Think I need to get the frame and carefully measure whats needed.

johngti

Bar Shaker wrote:

If both were painted the same colour, you would never know which was which.

Seat posts are so stiff and so resistant to tubular compression that they are the one element of a bike that will do nothing to enhance the ride comfort.

Isn't it more to do with vibration damping properties of different materials? Flex along the length of the tube might be similarly low but I was under the impression that CF has a greater degree of damping relative to its stiffness which would clearly have an impact on comfort over the longer term.

I'm probably completely wrong of course!

cycleclinic

All ride comfort improvemets are vibration dampig improvements but most of this comes from the tyres and other soft parts. The hard bits prvovide minimal improvement.

topdude

As stated above, think about the movement and shock absorbtion available in :

The rubber tyre
The air filled tube
Flex in the wheel / spokes if not too stiff
Movement of the saddle hull
Compression of the saddle foam
Gel in your shorts

Compare that to the possible movement available in a tubular seatpost :?

Now if someone wants a carbon post because it looks good that's fine but lets not endow it with magical properties :roll:

Bordersroadie

topdude wrote:

The rubber tyre
The air filled tube
Flex in the wheel / spokes if not too stiff
Movement of the saddle hull
Compression of the saddle foam
Gel in your shorts

+
The frame material/design/geometry

I just moved from aluminium frame to Ti with identical wheels/tyres and components and the road damping is materially improved. I've never ridden a carbon bike before but I assume that they may give the same contribution to a better damped ride.

BillyMansell

topdude wrote:

As stated above, think about the movement and shock absorbtion available in :

The rubber tyre
The air filled tube
Flex in the wheel / spokes if not too stiff
Movement of the saddle hull
Compression of the saddle foam
Gel in your shorts

Compare that to the possible movement available in a tubular seatpost :?

Now if someone wants a carbon post because it looks good that's fine but lets not endow it with magical properties :roll:

A couple of things you've missed off your list are human subjectivity and cognition both in terms of rider feel and technical understanding, in particular here has been the misplaced notion expressed a couple of times that a seatpost can offer no comfort as it doesn't compress along its length. No-one here had said a seatpost does compress along its length (unless it's a dropper) but rather they can provide comfort through flex on other axes.

Whilst it cannot be denied that there are seatposts designed and engineered to flex on other axes, the Syntace P6 mentioned previously can flex up to 20mm rather than the 10mm I had stated, whether someone perceives an improvement in ride quality may be down to the individual.