Having just built up a gravel/adventure/not-quite-a-road-bike I was pondering “posh” seatposts of the non-moving variety.

For the initial build-up I have just put on a cheap Cinelli Vai (27.2mm) seatpost based almost entirely on it being the right size, in stock and cheap. It seems fine, and does a stellar job of keeping my saddle attached to my bike but I was wondering if there’s a noticeable difference between that and (for example) a Thompson Elite for ~£60, or a Zipp SL for ~£120 and that’s without looking at the Ali/Carbon question?

Is it compliance, or weight generally that warrants the difference? If compliance is it noticeable (note I’m not asking if it’s “worth it” as that obviously depends on the individual) and is there a point of diminishing returns?

Is a ~£60 a big step up from a £20 one for example, but then you start paying for a name/miniscule weight differences?

Genuinely interested, I’m running 42c tyres at ~30psi tubeless so I’m not short of compliance as it is. Perhaps the seatpost becomes a bigger differentiator when you’re running skinny road tyres at 80PSI?

Decent carbon or Ti posts will add a bit of welcome give. Thomson will be a) slightly undersized and 2) stiffer than a scaffold pole.

Interested too.

Currently using a 27.2 Thomspn layback on my Roadrat and was the under the impression it’s apparently a fairly rigid/unforgiving post. Also interested in something more compliant although suspect the cost will be quite a bit extra. I’ve seen those Specialized posts with a weird ‘swan’s neck’ clamp for extra compliance but unsure how much I’d notice.

Never noticed any difference between one seatpost and another, except the pricy ones are prettier and more in keeping with the rest of the build of the bike.

Decent carbon or Ti posts will add a bit of welcome give. Thomson will be a) slightly undersized and 2) stiffer than a scaffold pole

Easy one to blind test wouldn’t it.. 😉

If you feel your post hasn’t got enough ‘give’, try letting a couple of psi out of the tyres.

I’m definitely not averse to buying something just because it’s nice to look at, especially if I can loosely justify it to myself in terms of compliance. I just wondered if it’s an Emperors New Clothes situation.

I had a carbon seatpost on my BFe when I first built it up, and it was surprisingly comfortable but it also had 2.3″ tyres and a steel frame which will both have a greater or lesser effect on the ride as well.

I can certainly tell the difference in compliance between a carbon seatpost and a thompson.  there is also weight if that bothers you

Yes, in some cases.

My Canyon VCLS (the original ‘solid’ post not the leaf spring one) is noticeably more comfortable than the alloy Ritchey post it replaced.

And yes, Thompson are like a scaffold pole.

If you feel your post hasn’t got enough ‘give’, try letting a couple of psi out of the tyres.

<div>Like the “why buy an XC bike when you could ride an enduro gnarpoon and just have a poo before the ride” hypothetical question, you can have your cake and eat it, in this case you can have a comfy ride and not pinch flat.</div>

why buy an XC bike when you could ride an enduro gnarpoon 

Ooh yeah, exactly like that.

Perhaps the seatpost becomes a bigger differentiator when you’re running skinny road tyres at 80PSI?

Not for me.  I ride a bike (on road and off road) with 25c tyres and seat post makes absolutely no difference.  I don’t have a massive amount of seat post exposed and my seat angle is fairly steep so would be surprised if one seat post was flexing any more than another and if even so I am pretty sure I wouldn’t notice it.

I just wondered if it’s an Emperors New Clothes situation.

100%.  Be a good one for a blind test to see if the princesses can feel their pea as it were.

I personally, bought one of the Niner full carbon posts for £50odd from Stif. 1, cos it was a bit of a bargain; 2, cos it looked nice. Then I scratched it 🙁

The USE Ti Sumo I have on my Soda is certainly noticeably flexy – I can definitely feel it “spring” if I drop myself back onto it. Its also developed a gentle curve after 10+ years of abuse. Long time since I’ve ridden that bike with any other post, mind.

I think to get proper benefit from “comfortable” seat posts you need to be using a skinny one, and have plenty of it sticking out the frame (I have a bit over 300mm of 27.2 dia  sticking out of the Soda). On a gravel bike that’s been built to maximise frame luggage capacity, with not much stand over, and therefore less exposed post, it’ll be a much more subtle effect.

On my Bokeh I choose between 2 different seatpost/ saddle combinations. No1 is a fizik carbon seatpost with fizik carbon railed saddle, No2 is a Thompson with a fizik steel railed saddle. The difference is because I have a Carradice Bagman support on the metal setup for lightweight packed touring, which I’d clearly not want to do with the carbon combo.

TBH I don’t really notice any difference between the two, but I suspect the carbon is a little lighter and maybe a touch less buzzy.

Ooh yeah, <em class=”bbcode-em”>exactly like that.

Yup, exactly. 😉

Wasn’t meant literally, and it’s obviously not true, but plenty of people will tell you it’s not worth saving 2lb off a bike as they’ve had a bigger poo.

Same with comfy seatposts, steel frames, high TPI tyres.Yes you could achieve a similar increase in comfort with a couple of PSI less each time, or you could keep the tyre pressure the same and do those things.

I’m already finding the bike surprisingly comfortable, and with 650B x 42C tyres running ~30psi it’s hardly an out and out race machine so I’m not too worried about the weight. I will be upping the road mileage (and tyre pressures) for some more road-based rides over winter though.

My initial thoughts were that a seatpost change would probably be negligible compared to the give in my tyres currently, but maybe a carbon post would add a little more give.

Thompson are definitely off the list though after this thread, I may keep an eye out for something carbon! Weight isn’t a massive concern, the bike was ~10.5kg on the bathroom scales before I swapped the tubes out and fitted the skinnier tyres so not a monster but not light enough that 50g on a seatpost will make any difference at all.

I didn’t think about the amount of exposed seatpost but it’s a good point! I don’t have a lot out of the frame, due to my midget legs;

[url=https://flic.kr/p/2bC7wpF]IMG_0816[/url] by James Fabian, on Flickr

How about the Exotic CarbonCycles stuff.. reasonable price, well made and durable…

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Thompson are definitely off the list though after this thread,

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I didn’t think about the amount of exposed seatpost but it’s a good point! I don’t have a lot out of the frame, due to my midget legs;

Not particularly relevant to you, but to anyone else reading the tread it’s worth remembering that a carbon post for a road bike takes much less of a beating than a mountainbike because the latter has 5″ more post showing. The flip side of that is that even a stiff post has some give if it’s twice as long.

I’ve got a thompson on my vagabond and it’s fine (could be more compliant but it’s not bad), but I’m not sure I’d put a roadie seatpost in there even if it did reach the minimum insertion (I don’t think it would anyway).

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I had an FSA carbon post on my gravel bike which got damaged after it kept slipping. Changed to a Thompson Elite which I had in the garage, no difference in comfort. Having said that I’d like to try the Canyon one if it was less than the price of a dropper post.

we’re in magic vertical compliance territory a bit here aren’t we? how much movement in the seatpost compared to the flex in the saddle are people expecting there to be?

I’ve got a Thomson on my hardtail. It also has carbon rear stays with a bit of flex…

we’re in magic vertical compliance territory a bit here aren’t we? how much movement in the seatpost compared to the flex in the saddle are people expecting there to be?

Canyon reckon 20mm deflection for the VCLS 2.0 and IIRC about 7mm in the VCLS which is the one I’ve got.

It’s not just movement though, a titanium post acts as a spring too, what the Canyon does which is clever is use Basalt fibres which have much higher hysteresis than carbon, so when you bounce it doesn’t bounce back as hard, just like suspension damping. Whereas some Ti posts feel like your riding a see-saw.

Ride behind someone on a long 27.2 Ti seat post and you’ll see the deflection / compliance.

It just feels like it’s making the trails breathe

My main criteria for seatpost selection is one that doesn’t snap or bend.

for a given material, the amount of flex in a tube is proportional to its outer diameter and nothing else – I think this might be the case across all metals, but I don’t know. Therefore the worlds cheapest alu seatpost will have exactly the same flex characteristics as the worlds most expensive, assuming they have the same profile and I guess the same method of attaching the same head (there could also be flex in the head and head-to-stem attachment, but I’m pretty sure it’d be negligable compared to the amount in the post).

I don’t know if this holds up for carbon vs metal, but given most carbon structures appear to be approximately the same diameter of their metal counterparts, I would say maybe?

for a given material, the amount of flex in a tube is proportional to its outer diameter and nothing else – I think this might be the case across all metals, but I don’t know.

Nope, two good obvious examples are:

1) Butted frame tubes. If your statement was true a basic plain gauge 4130 frame would ride just the same as a 953 frame.

2) Seatposts, most mid-higher end seatposts are profiled with an oval section inside, so it effectively has a different wall thickness fore/aft Vs laterally.

For carbon it’s even less true as you can adjust the layup, modulus of the fibres and resin content to adjust it’s properties in ny dimension* you like.

*we’re talking bending stiffness, for all practical scenarios on a bike tubes are pretty much immune to compression/elongation, although they can bow which amounts to compression if you’re considering a tube as a side of a a triangle.

for a given material, the amount of flex in a tube is proportional to its outer diameter and nothing else – I think this might be the case across all metals, but I don’t know. Therefore the worlds cheapest alu seatpost will have exactly the same flex characteristics as the worlds most expensive, assuming they have the same profile and I guess the same method of attaching the same head (there could also be flex in the head and head-to-stem attachment, but I’m pretty sure it’d be negligable compared to the amount in the post).

Flex is based mostly on OD but also on wall thickness. If it wasn’t, a 30mm bar would no stiffer than a 30mm tube 🙂 And a stronger grade Al can have a thinner wall so it flexes more than the thicker wall weaker-grade Al post.

OP, you have almost no post showing so it’ll make no difference. A ti rail saddle would be more effective.

It’s all about the length of the lever and the stiffness of the tube. I took a Ti post off my Brompton recently as it was far too flexy for my linking. Over that long a post the difference between the Ti and the steel post was too great.

A lot of brands are going back to 27.2 diameter seatposts on their road and gravel bikes as the smaller diameter is an additional way of adding comfort to their bikes, so yes, seatposts do make a difference.

Obviously, you can’t change the diameter on your frame, but you can add comfort by changing seatposts and drop weight. The longer the seatpost and the greater the external length, the greater the benefits.

Personally, £60 to £100 is my price range.

@jameso I hadn’t considered the saddle itself, but I do need to swap out the Charge anyway as the shape doesn’t really suit me (although it looks nice) so I may think about going higher-end on the saddle instead. I’m not desperate for any more compliance but if I’m changing something anyway, it’s worth maximising the impact of that change.

Do carbon rail/shell saddles tend to be optimised for weight rather than flex in their layup?

It’s been an interesting thread, I’ve only ever had droppers on my mountain bikes as I only started about 4 years ago so it’s not something I ever thought about previously.

I took a Ti post off my Brompton recently as it was far too flexy for my linking.

…hasn’t the Brompton got a big squidgy spring between front and rear triangles? I notice that flexing a lot more than my post.

I’ve got a Moots titanium post on one bike, with about 250mm exposed. It’s got a lovely amount of give, but no damping at all so if I hit something hard while sitting down it will absorb a fair amount in flexing, but will spring back just as hard!

Do carbon rail/shell saddles tend to be optimised for weight rather than flex in their layup?

I would think both but with a bias towards weight.

A lot of brands are going back to 27.2 diameter seatposts on their road and gravel bikes as the smaller diameter is an additional way of adding comfort to their bikes, so yes, seatposts do make a difference.

Even if that made any difference it is not the question here as the OP is not changing the diameter of their seatpost.  They are asking whether one seatpost of same diameter is different than another, and more specifically if the more expensive one is better.

Not sure why the cost would matter as an expensive post could in theory be stiffer than a cheaper post.  You would hope the expensive post has been made better and used better materials though

I bet there’s people on here who can feel the play in their dropper post while riding too. Must be a nightmare being so sensitive 😉

S-Works COBL GBLR thingy on my tarmac bike  and yes, I can feel the difference.

I bet there’s people on here who can feel the play in their dropper post while riding too. Must be a nightmare being so sensitive 😉

Difference between play, flex and movement. Can you tell the difference between worn suspension bushings, a flat tyre, a blown damper in the shock?

S-Works COBL GBLR thingy on my tarmac bike  and yes, I can feel the difference.

This + lots, even with 42mm tyres, on a gravel bike.

I’d just like to apologies to Kerley for not adding a reply to the OP that met his expectations 😉

1) Butted frame tubes. If your statement was true a basic plain gauge 4130 frame would ride just the same as a 953 frame.

2) Seatposts, most mid-higher end seatposts are profiled with an oval section inside, so it effectively has a different wall thickness fore/aft Vs laterally.

neither of those do make any difference. A plane gauge frame does ride just like a posh tubed one, other than the fact it weighs a little more. An internally ovalised seatpost would have the exact same flex characteristics as a normal tube. What is changed is the overall strength of the tube, but strength and stiffness are not synonymous.

I would hazard a guess that the ovalised seatpost is ovalised to put more strength front-to-back – this would be the opposite of where you’d put it if you wanted flex (as presumably you want zero flex side-to-side)

I believe my previous statement that it made zero difference may technically be incorrect – however the difference is as small as to be negligible for the interests of discussion

Can you tell the difference between worn suspension bushings, a flat tyre, a blown damper in the shock?

Me? Yes!! Yes, I, can…

Worn bushings – you get off the bike and hold the saddle and you can feel a slight up & downy wobble.

Flat tyre – steering goes weird, mushy, pedaling is harder – until the sealant works.

Blown damper – never had that.

None even slightly similar to the difference between one rigid post and another. At least, not to me.

I’d just like to apologies to Kerley for not adding a reply to the OP that met his expectations

Don’t worry about it, not many people manage – although your reply was piss poor.

Says the man who said “You would hope the expensive post has been made better and used better materials though” 🙂