# Steel seat tube stock for 30.9mm post



## golden boy (Oct 29, 2008)

My wife wants a dropper post on the frame I'm building next for her. Apparently, she's more progressive than me. Anyway, I'd like the frame to accommodate a 30.9 post. A 27.2 dropper post sounds flimsy to me. I found a (forum) post here that claims Reynolds makes the tubing I desire, but I can't find a source for Reynolds tubing that does not require a business license.

Anyone know of other manufacturers that offer what I need? Or a source for Reynolds tubing that does not require a business license? Or, you have the tubing I need and you're willing to sell it to me?


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## todwil (Feb 1, 2007)

How about going to 31.6 seat post then you can use 1-3/8" .035 tubing with a .065
Slug at the end it fits the post perfectly.


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## shiggy (Dec 19, 1998)

golden boy said:


> My wife wants a dropper post on the frame I'm building next for her. Apparently, she's more progressive than me. Anyway, I'd like the frame to accommodate a 30.9 post. A 27.2 dropper post sounds flimsy to me. I found a (forum) post here that claims Reynolds makes the tubing I desire, but I can't find a source for Reynolds tubing that does not require a business license.
> 
> Anyone know of other manufacturers that offer what I need? Or a source for Reynolds tubing that does not require a business license? Or, you have the tubing I need and you're willing to sell it to me?


Size the seat tube for a 31.6 and use a shim.


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## Walt (Jan 23, 2004)

The 27.2 droppers are in no way flimsy and your wife will not break them. Gravitydropper has been making essentially the same thing for a decade and they still work great. Thomson and KS also have 27.2.

That said, assuming you want a larger diameter, do what Todd says and just do 31.6. You can get all the same posts and it is much, much easier.

-Walt


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## shirk (Mar 24, 2004)

I have a Gravity Dropper in 27.2 and it's in no way flimsy. Actually just bough another one at the annual bike swap for $30. Score.

With that said I will likely be getting my girlfriend a Reverb and would build a bike for her with 31.6 seattube as I am 99% sure she will prefer the feel and infinite adjustment of the Reverb.


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## Walt (Jan 23, 2004)

That's a good point. If you want a 2-position (ie, saddle up for pedaling, down for descending) setup the GD is a huge win. If you want to constantly tweak your saddle height then the infinite adjust setups are way better. The GD is also kind of klunky to operate (ie not slow/smooth when changing heights) but I could care less about that myself. To me it's a way to not have to stop and lower my saddle before a long descent, then stop again and make sure it's back in the right position for the next big climb. 

-Walt


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## shirk (Mar 24, 2004)

The GD can be ordered with multi position. The one I rode all last season is set up with 1 inch down or 4 inches down.

A friend rides one with 1 inch down or 3 inches down. He just recently set his up with a Fox DOS lever and wow is it smooth and better than the original GD lever. He rides singlespeed so it's positioned where a regular rear shifter would be and it's a boss set-up.


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## Walt (Jan 23, 2004)

Yeah, I can't use those ones because I have terrible knees from moto wrecks during my wasted youth, so if the saddle is 1" down it might as well be all the way down - I can't pedal unless it's all the way up anyway. 

The GD lever is a godawful piece of junk, yes.

-Walt


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## golden boy (Oct 29, 2008)

OK then, I'll stick with the Nova externally-butted 28.6 seat tube and get her a 27.2 dropper post. I know nothing about dropper posts. Good to hear that folks like the 27.2 models. I'm planning my next personal frame to be for a 27.2 post, but my plan is to buy a ti setback post for added comfort. It's nice to know I can go that route, but still have the option to switch to a dropper post. It's tough being a retro-grouch in the ever-evolving mtb world.


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## jeff (Jan 13, 2004)

Did you just say Boss? Haven't heard that since 72". 


shirk said:


> The GD can be ordered with multi position. The one I rode all last season is set up with 1 inch down or 4 inches down.
> 
> A friend rides one with 1 inch down or 3 inches down. He just recently set his up with a Fox DOS lever and wow is it smooth and better than the original GD lever. He rides singlespeed so it's positioned where a regular rear shifter would be and it's a boss set-up.


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## golden boy (Oct 29, 2008)

Resurrecting this thread...

To reiterate: My goal is to make a steel bike frame that will accommodate a 30.9mm seatpost.

My request: Name a source, manufacturer and part number for a steel tube that will allow me to achieve the above goal.

Ideally, I'd like a tube that is ready for reaming to fit a 30.9 post, but optionally, I'll consider an oversized tube that can be shimmed down to 30.9. I can't for the life of me find a source for such a tube.


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## adarn (Aug 11, 2009)

Get yourself a lathe, or at least a friend with one.


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## Walt (Jan 23, 2004)

+1 to that. Or do 31.6. Ask Feldybikes to help you out.

-Walt


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## afwalker (Apr 26, 2012)

Golden Boy,
I have 3 CX2463-3431 853 31.6 ID seat tubes if you'd like one shoot me a pm.
It looks like you'd like the Reynolds CX2287 853 30.9 ID, maybe on my next order in a couple months?
cheers
andy walker
walker bicycle co.
andywalker.info


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## golden boy (Oct 29, 2008)

Thanks Andy, I'll let you know. Seems like I've heard 853 is a b*tch to ream, no?


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## toby_g (Jul 29, 2008)

Columbus do an externally butted seat tube for MTBs. Available in 550mm or 635mm lengths. 0.7/0.5/0.9 butts. It is 32.7mm OD at the bottom, and the external butt is 33.5mm OD. It takes a 31.6mm seatpost, which can be shimmed to 30.9 (I did so on my last build). The lower butt on the 550 is 250mm and can be shortened by up to 165mm, giving a range of seatpost lengths down as low as 385mm.

Code: ZON113...001 (replace ... with the chosen length). 

I get mine from Ceeway.


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## 18bikes (Jan 15, 2007)

Reynolds also do the mentioned seattubes in 631, not got part numbers to hand but can supply if needed. Same profile as the 853 off the top of my head and the same 4 lengths

Matt


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## afwalker (Apr 26, 2012)

Yes, CX5287 in 631. 33.1/30.9id 1.1/0.55/.9 550 length. Only see 1 length, maybe they added more.
^Matt, you find 853 hard to ream?
cheers
andy walker


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## 18bikes (Jan 15, 2007)

yep, 853 can be a pain if it gets distorted, I tend to use 631 now.

Mastt


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## alshead (Oct 2, 2007)

I can confirm that the ...sorry- I wasn't home when I wrote this before. The tube I meant is the VERUSSTMAG2 tube from HJ is tapered to a 31.6 ID on one end and could take a shim for a 30.9 post (that's my plan, anyway).


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## Sepp (Oct 13, 2007)

I am looking at this seat tube to be combined with a 30.9mm seat post. After reaming this would get me theoretically a 0.8mm wall, which seems not much.
Does this work, or is it meant to be used with a sleeve for a smaller diameter post?

http://www.henryjames.com/Cpdf/seat-tubes/ZON113560002.pdf


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## Walt (Jan 23, 2004)

You will have to sleeve that.

Also, .7mm at the bottom? Sketchy...

-Walt


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## Sepp (Oct 13, 2007)

Walt said:


> You will have to sleeve that.
> 
> Also, .7mm at the bottom? Sketchy...
> 
> -Walt


OK, I ordered a different size with sleeve.

Here's a question regarding steel handlebars: I have 22.2 x 0.8mm tubes laying around, and now am thinking of building my own bullmoose style bar.

Is 0.8mm ok for that, or would you go thicker at all costs? To be combined with a flatland XC hardtail. 150lbs rider weight.


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## Walt (Jan 23, 2004)

I have never built a handlebar, so I couldn't tell you. But it's certainly an item that would really suck to have fail... and 0.8mm x 22 is not a lot of metal.

-Walt


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## Sepp (Oct 13, 2007)

Walt said:


> But it's certainly an item that would really suck to have fail... and 0.8mm x 22 is not a lot of metal.


)


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## dr.welby (Jan 6, 2004)

I seem to remember from my BMX manufacturing pals that standard race bars were 0.049". Checking my collection of random steel handlebars, I only found one that thin and the rest were closer to 0.058" and up.

So I would say 0.8 is most definitely too thin.


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## Eric Malcolm (Dec 18, 2011)

My bars of my own design start at 25.4 x 0.9mm at the clamp area and reduce to 22.2 x 0.9 for the grips/levers. My riding is of a less stressful flat riding nature and I am comfortable with that, but if I was to indulge in jumps and carried alot of air, crashed alot and riding conditions are consistantly 'rough' I would suggest 1.2mm.

Eric


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## Sepp (Oct 13, 2007)

That's great info - thank you

I have a few feet of 22.2x0.8 and wouldn't know what to do with it other than making handlebars, so I will use it for practice, and do some tests to see if it is what I am looking for.


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## Walt (Jan 23, 2004)

Sepp said:


> That's great info - thank you
> 
> I have a few feet of 22.2x0.8 and wouldn't know what to do with it other than making handlebars, so I will use it for practice, and do some tests to see if it is what I am looking for.


Chainstays for a road or cross bike, crossbrace for a dropped-toptube mountain bike?

Don't make a handlebar with it.

-Walt


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## Eric Malcolm (Dec 18, 2011)

I agree with Walt.

I made a Cross tubed Gravel Grinder that had twin down tubes made out of 22.2 x 0.5mm tubing. The cross tube braced the down tubes at something like 1/4-3/4's from the head tube and required a bit of sleeving at the H/T end to keep things strong.
You could get creative and do something similar as 0.8mm would be strong enough to do the task unbraced. The frame is very rigid from a lateral flex veiwpoint and would follow Colnago road bike themes from the racing scene before they were banned by the ICU.









Eric


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## shirk (Mar 24, 2004)

Interesting that you should re-post that bike Eric, I was just looking at the original thread where you posted that one and other one like it you built. I think I was searching for info on 1/2" seat stays. It's inspired me to give some 1/2" double chainstays a go on an upcoming build.


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