# 31.6x450 long seatpost needed



## dbatomf (Jan 27, 2016)

I recently downsized my frame due to being over extended on a XL frame. I now need to find a 31.6x450mm seatpost but the only thing I can find at a reasonable price is chinese carbon on amazon or ebay. <$70 is about what I can afford. 

I am of the long leg/short torso variety at 6'1" I ride a 61cm roadie with massive drop. 

My drop requirements are complicated by the fact that my new frame has a short seat tube and very short seat tube above the top tube. 

There has been many threads on this topic but not many recommendations on seat posts. I just want to see if there is a reputable brand with what I need before I go and order something from china or spend more money than I should on a dropper post.


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## TooTallUK (Jul 5, 2005)

Honestly? Find a frame with a different geometry that fits you, sell your current frame and buy the other frame. Once you start putting seatposts like that on a bike you're putting lipstick on a pig.
How heavy are you and how much seatpost do you need to be showing above the top of the seat tube?


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## dbatomf (Jan 27, 2016)

I'm 200lbs and need a little over 11 inches exposed which I have seen plenty of examples on here. I think the practicality of finding a frame that fit better would take me well out of my price range. At this point I've just accepted that I am one of those riders with the ridiculous seatposts. 

At 6'1" my inseam is 37.25" which ime is pretty ridiculous. Anything I get on I max out the height trying to get proper leg extension.


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## Muirenn (Jun 17, 2013)

clhnsn55 said:


> I'm 200lbs and need a little over 11 inches exposed which I have seen plenty of examples on here. I think the practicality of finding a frame that fit better would take me well out of my price range. At this point I've just accepted that I am one of those riders with the ridiculous seatposts.
> 
> At 6'1" my inseam is 37.25" which ime is pretty ridiculous. Anything I get on I max out the height trying to get proper leg extension.


Well, I'm not a clyde, but I'm 5'7" with a 33.3 inch cycling inseam. My Surly Krampus has a 375 mm seat tube, with a 409 mm Thompson seatpost, just to be safe. The post is maxed out on a small Krampus. Their medium is too long in the cockpit. Looking around, a lot of mountain-bikes in my size have tiny seatposts (especially women's, which I am). To get a larger seatpost, I end up on a men's, with a shorter headtube, which I don't really want on a mountainbike. I definitely fall in between men's and women's sizing in both mountain and road (I've really long arms, so my reach isn't short). Think I'm leaning towards women's specific for the next mountain bike. If I can find something that checks all the geometry boxes.

What make and model bike is it? Do you have a link to the geometry chart?

Also, what is your seatpost height from the center of your bottom bracket to the top of the saddle?


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## Cayenne_Pepa (Dec 18, 2007)

You're gonna need an custom alloy or titanium long post. Extra long carbon of even the very best name brands will be weak, once past 350mm at the minimum insert level.


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## Le Duke (Mar 23, 2009)

Cayenne_Pepa said:


> You're gonna need an custom alloy or titanium long post. Extra long carbon of even the very best name brands will be weak, once past 350mm at the minimum insert level.


I'm going to say that's dubious at best.

Sent from my XT1585 using Tapatalk


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## Muirenn (Jun 17, 2013)

Okay, working the few numbers you've given me and comparing to my own proportions as a guide:

My inseam is 84.58. My Krampus has a 375 mm seatube, and a 409 mm seatpost. That total is 784 mm. From the center of the crank to the top of the my saddle is 730 mm. Doesn't really add up, but of course there is some overlap. Whatever. It's (almost) maxed out, but I do have a Brooks saddle, which is taller than many saddles. If I used the other saddle I like, a Specialized Romin Gel, I might not be able to adjust it high enough. I think the minimum seat tube I should use is around 425 mm. The Krampus is a size small, I think the medium ECR would fit better as it has a proportionately shorter tt to stack, but I love the way the Krampus handles, and don't really want to switch it out. (I might, eventually, but I want a trail bike, not a bikepacking machine). 

Your inseam is 94.61 mm, just over 10 mm higher than mine. You could (maybe?) get away with a 500 mm seat tube, but 525 would be better. I could be off, and perhaps that is what you are using now, if so, are you sure about the inseam? Anyway. A bike with that size seat tube might make you too stretched out, as the entire bike size increases proportionately. You need to look for a larger bike that is more upright in the front, with a higher headtube and stack, proportionate to the overall size, this will give it a shorter reach, and possibly a longer seat-tube, (unless head tube angle makes the reach longer). I don't have so many mountainbike geometries memorized, but the Salsa Vaya is very upright, and so is the Fargo. If you are on a hard-tail, or full suspension, the same should apply, but I don't know which is which without looking.


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## watts888 (Oct 2, 2012)

I'd start with one of the $15 450mm alloy seatposts off ebay, just to make sure you fit properly with a longer seatpost. If you haven't been able to ride this bike with the proper seatpost height, hard to justify an expensive seatpost.

After that, have you considered a dropper post? Most of them are excessively long to house the dropper mechanism.


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## dbatomf (Jan 27, 2016)

watts888 said:


> I'd start with one of the $15 450mm alloy seatposts off ebay, just to make sure you fit properly with a longer seatpost. If you haven't been able to ride this bike with the proper seatpost height, hard to justify an expensive seatpost.
> 
> After that, have you considered a dropper post? Most of them are excessively long to house the dropper mechanism.


That's probably a good idea. I have considered a dropper post but its hard to justify around here (flat). It would be just for the sake of saddle height with big weight and cost penalty but it may come to that.

BTW my BB to saddle is ~32"... on my road bike it is ~34".

The frame is a ridley ignite a29 with a 100mm fork


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## leeboh (Aug 5, 2011)

Be sure to check out thompson for seatposts. What about a riser bar to get your hands up higher? Checked out Zinn bikes? Custom and other stuff for us large types. He would be a good source for some solution ideas.


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## Surfdog93 (May 30, 2005)

There is a company in Germany (don't recall the name) that manufactures very long carbon seat posts, but super-expensive. The longest I have found came with my 2012 and 2014 Trek Superfly's, so check Bontrager ....1000's of miles on them without fail and really like the one-bolt adjustment. Some of the dropper-posts are quite long as well. I also have aluminum Thomson, 430's I believe....reliable, but don't like the 2-bolt adjustment.


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## Cayenne_Pepa (Dec 18, 2007)

Le Duke said:


> I'm going to say that's dubious at best.
> 
> Sent from my XT1585 using Tapatalk


Dubious? What are you talking about? The wall thickness of a 450mm carbon post still remains the same. It's gonna get stressed.


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## Le Duke (Mar 23, 2009)

Cayenne_Pepa said:


> Dubious? What are you talking about? The wall thickness of a 450mm carbon post still remains the same. It's gonna get stressed.


Are we pretending that it's not possible to add layers of carbon in high stress areas?

The wonderful thing about composites is that you can effectively "tune" them via additional layers, different orientations, different types of fibers, and different resins.

Sent from my XT1585 using Tapatalk


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## Muirenn (Jun 17, 2013)

Le Duke said:


> Are we pretending that it's not possible to add layers of carbon in high stress areas?
> 
> The wonderful thing about composites is that you can effectively "tune" them via additional layers, different orientations, different types of fibers, and different resins.
> 
> Sent from my XT1585 using Tapatalk


But thick, high thread-count carbon is out of budget.


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## Muirenn (Jun 17, 2013)

clhnsn55 said:


> That's probably a good idea. I have considered a dropper post but its hard to justify around here (flat). It would be just for the sake of saddle height with big weight and cost penalty but it may come to that.
> 
> BTW my BB to saddle is ~32"... on my road bike it is ~34".
> 
> The frame is a ridley ignite a29 with a 100mm fork


Darn it. Looks like Ridley doesn't publish the stack and reach. What I want is to find out the reach especially, and locate a bike that has a longer seat tube, but the same reach. (Even if you don't want to do anything about it, there is always next time, people with odd fit requirements need to figure out all this stuff the hard way, usually). And probably a higher stack. The Head tube on the large is only 115 mm, which is quite small. Definitely appears to be a low front end in pictures, but that can be misleading. Any idea what the stack and reach are?


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## Gigantic (Aug 31, 2012)

TooTallUK said:


> Honestly? Find a frame with a different geometry that fits you, sell your current frame and buy the other frame. Once you start putting seatposts like that on a bike you're putting lipstick on a pig.
> How heavy are you and how much seatpost do you need to be showing above the top of the seat tube?


running too long of a seat post can put a lot of stress on the junction of the seat stays, seat post and top tube, potentially leading to premature frame failure. Don't ask me how I know this.


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## Muirenn (Jun 17, 2013)

Okay, it would be better if we knew the stack and reach on the Ignite, but here is a possibility. The Niner has a longer effective top tube, but a higher head tube. It's possible the reach is shorter, which would mean it might fit. Assuming the reach on the Ignite is correct for you, I'd look for a bike with similar numbers to the Niner, with emphasis on the reach. If you could get an accurate stack and reach on your bike, that would help. Generally, you would expect a bike with a higher head tube to have a higher stack, and shorter reach. It's certainly a great deal if it fits. If the reach on the XL Niner is significantly longer than the Ignite, then it's too big. Effective top tube is effected by the head tube angle; not sure about reach. Maybe not? Or it depends?

Niner Air 9 SRAM Jenson Bike 2013 > Bikes > Mountain Bikes | Jenson USA

Out of curiosity, what make and model is the bike you replaced? If I knew the too large reach, that could determine alternative sizing better.


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## dbatomf (Jan 27, 2016)

I replaced a nashbar 29er frame. I am happy with the stack as generally ride in an aggressive position. In addition I have pretty long arms which makes the stack height have a less dramatic effect on my position. The problem with extending the reach (increasing ett or overall frame size) is the amount of weight it takes off of the front wheel. I really struggled with seated cornering due to front tire traction. That's the problem, at least for me, with a larger or longer frame. I keep a couple spacers above my stem just so I can raise the bars for endurance rides but I have yet to actually do it.

My real problem is leg extension. I could probably find a frame with a less dramatic TT angle or with a longer seat tube extending above the TT but I would have to keep everything else the same. I'm pretty close to getting there as it sets. Just need a little over one more inch in the post.


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## Muirenn (Jun 17, 2013)

Unless I'm looking at the wrong frameset, the Nashbar 29er has a shorter tt, and higher head tube. ?? Didn't you say the old bike felt longer? That 19" would fit me better than my current bike, and I'm only 5'7". Am I missing something?











clhnsn55 said:


> My real problem is leg extension. I could probably find a frame with a less dramatic TT angle or with a longer seat tube extending above the TT but I would have to keep everything else the same. I'm pretty close to getting there as it sets. Just need a little over one more inch in the post.


Yes, that describes my Krampus fit. Too bad a 409mm seatpost won't work. That is the tallest available. At least in a 27.2. Maybe a 31.6 is available in longer sizes? Great post. High quality and strong.


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## dbatomf (Jan 27, 2016)

I'm not sure which where you found that info but I'll bet it's for the 29er alloy frame that they sell. They have a couple different 29er frames that are deceptively similar in looks and names. I'm just going of measuring the bikes in person.

I ended up ordering the cheap carbon seatpost on Amazon for fitting. I have to say that the construction is pretty confidence inspiring. After I had it installed it most apprehension I had was eased. I'll ride it until I can afford a dropper post.

Hers a picture of the bike with last seatpost. It is currently about 2.5cm higher.


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## Muirenn (Jun 17, 2013)

That doesn't look excessive, by my standards, anyway! That's a nice bike. Ridley makes quality stuff. 

The geometry chart was for the steel frameset.  Kind of think that 19" chromoly might be good for me, but I don't need it!


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## dbatomf (Jan 27, 2016)

Just updated my last post to say that the pic was before raising the seatpost 2.5cm (it's not a very dramatic difference). My previous frame was the AT29 frame. The frame is actually different than the alloy 29 frame they sell as a frame only (both blue btw).

Yes. Very good frame from Ridley. First ride yesterday and it was awesome. More front wheel traction. Rear wheel breaks free when I want it to, although this may be partially due to upgraded brakes. No sacrifice in stability when sprinting. The overall setup is less forgiving (flexy) which means I have to focus a bit more on hitting the right lines but that's what I was going for.


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## Muirenn (Jun 17, 2013)

Yeah, I saw your update. Still looks like it would be less than half seatpost, so could be worse. And yes, it was definitely the cromoly geometry I uploaded.


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## NYrr496 (Sep 10, 2008)

Cane Creek might make a Thudbuster that fills the need. I have a gigantic one on my Dahon.


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## TraxFactory (Sep 10, 1999)

If your still in need....a 450 and 500! both in Europe.

wiggle.com | BBB BSP-23 Longscraper MTB Seat Post | Seat Posts

https://www.bike-components.de/en/Shannon/Hardcore-Sattelstuetze-500-mm-p22129/


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