Anyone elsed notice Rivendell's freaky, inconsistent seatpost standards?

[Matt D]

So what's the deal with Grant's thinking on seatposts? There are a lot of Rivs that come with the 26.8mm seatpost standard. Roadini, Sam H., and the lower two sizes of the Clem come with 26.8 and I believe all the others are made for 27.2 or 29.8 in the case of the Hubbuhubbuh and 59cm Clem.

So, my questions...

Considering how hard they are to come by outside of the stock Kalloy seatposts Rivendell ships with frames, "Dajia Cycleworks" (really just a Velo Orange house brand), and Nitto stuff, why use it at all? Does the 0.4mm jump really impart much of a benefit to ride quality? If it does and you're already willing to forego wide compatibility why not go straight to 26.0? When 26.8 isn't used, why isn't it used? Why jump straight to 29.8 for the largest Clem? If a 59cm Clem needs such a beefy seatpost shouldn't the 57 and 61 Roadinis get one too, or are they not offroady enough? Why do tall Clems have to use a seatpost in a size Rivendell doesn't even sell? Do the Roadeo and Homer use 27.2 so people can use more conventional with-the-times parts on it and if so, why not others too?

I've always been baffled by this so if anyone with inside knowledge can explain this to me I'd love to hear why.

[Joe Bernard]

I believe it's a matter of what seatlug is used for a particular model. 27.2 was on the MUSA frames, 29.8 was the socket-style lug originally used on all Clems and now only the big ones, 26.8 is the lug currently used on the smaller Clems and all MIT fully-lugged bikes.

[Laing Conley]

Seat post size is the inner diameter of top of the seat tube (usually single butted - thin part at the top) - change the tube = change the seat post. When the Sam got 0.2 thicker tubes (same outer diameter = same lugs), the seat post got smaller -> 27.2 minus 2 x 0.2 = 26.8.


Laing Conley

--
You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bun...@googlegroups.com.
To view this discussion on the web visit https://urldefense.proofpoint.com/v2/url?u=https-3A__groups.google.com_d_msgid_rbw-2Downers-2Dbunch_ab572e71-2D3b22-2D4f3f-2Dae42-2De0bfbe0955b1-2540googlegroups.com&d=DwIFaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=fbpz-LhLhQnqxV9ePfEuoQ&m=zdOnZkL4-imZ2uJ9jNdVckdW6eHIum54VBbtRYEfZX4&s=IC6ULtQUHCeB8oelCIAYrk-8wx3ClbewZBhUNk-l_gQ&e=.

[Bill Lindsay]

Freaky and inconsistent is a little much.

28.6mm is the outside diameter of a normal seat tube. 0.7mm wall thickness yields a 27.2mm seatpost. 0.9mm wall thickness yields a 26.8mm seatpost. The thinking is spec tubing that is stout enough for the application and the seatpost diameter is a result.

If Grant wanted to take the easy way, use off the shelf tubing for all bikes and do what everybody else did, then all Rivendells would be 27.2mm. For the Silver tube sets that he decided to have made, he decided to spec a little bit thicker wall thickness for a little bit more stoutness.

It’s totally easy to find 27.2mm seatposts. It’s totally easy to find 26.8mm seatposts. If you are having a hard time finding the right size, let us know and we’ll help you find one.

Bill Lindsay
El Cerrito Ca

[Eric Norris]

SheldonBrown.com has an entire page devoted to seatpost sizes:

https://www.sheldonbrown.com/seatpost-sizes.html 

If you have an older bike, things get interesting. I have a ‘72 Cinelli (26.2mm) and a ‘71 Motobecane (26.4mm) that both require seatposts that can be somewhat difficult to find.

--Eric N

On Nov 11, 2019, at 11:31 AM, Laing Conley <lco...@brph.com> wrote:

Seat post size is the inner diameter of top of the seat tube (usually single butted - thin part at the top) - change the tube = change the seat post. When the Sam got 0.2 thicker tubes (same outer diameter = same lugs), the seat post got smaller -> 27.2 minus 2 x 0.2 = 26.8.

To view this discussion on the web visit https://groups.google.com/d/msgid/rbw-owners-bunch/BN8PR14MB2883A8FFFDCFA7AF8A6D0680C3740%40BN8PR14MB2883.namprd14.prod.outlook.com.

[Brewster Fong]

There appears to be two major sources for 26.8 and 29.8mm seatposts. Kalloy, as you mentioned, and Thomson. Not sure anyone else, including Nitto sells a 29.8mm.Good Luck!

[Matt D]

Fair enough, it's only freaky and inconsistent by modern standards I suppose. That bit about the tubeset diameters makes a lot of sense, thanks. Anyone have a list of what tube specs have been used and when? That would be interesting to see.

It's way easy to find 27.2 as that's the most common current road standard. It's not hard to find 26.8 per se, there just isn't much variety. Not that you can't be happy with a Nitto post for the rest of your life, of course, but that lugged one is neat and 27.2 only.

Eric, Velo Orange had Kalloy make them 300mm long one-bolt posts in a range of weird sizes for $25 a pop. 25.0/4, 26.2/4/8, 27.0/2. Fantastic resource for older bikes.

On Monday, November 11, 2019 at 1:48:29 PM UTC-6, Eric Norris wrote:

SheldonBrown.com has an entire page devoted to seatpost sizes:

https://www.sheldonbrown.com/seatpost-sizes.html 

If you have an older bike, things get interesting. I have a ‘72 Cinelli (26.2mm) and a ‘71 Motobecane (26.4mm) that both require seatposts that can be somewhat difficult to find.

--Eric N

On Nov 11, 2019, at 11:31 AM, Laing Conley <lco...@brph.com> wrote:

Seat post size is the inner diameter of top of the seat tube (usually single butted - thin part at the top) - change the tube = change the seat post. When the Sam got 0.2 thicker tubes (same outer diameter = same lugs), the seat post got smaller -> 27.2 minus 2 x 0.2 = 26.8.


Laing Conley  


-----Original Message-----
From: rbw-owne...@googlegroups.com <rbw-owne...@googlegroups.com> On Behalf Of Joe Bernard
Sent: Monday, November 11, 2019 1:53 PM
To: RBW Owners Bunch <rbw-owne...@googlegroups.com>
Subject: [RBW] Anyone elsed notice Rivendell's freaky, inconsistent seatpost standards?

I believe it's a matter of what seatlug is used for a particular model. 27.2 was on the MUSA frames, 29.8 was the socket-style lug originally used on all Clems and now only the big ones, 26.8 is the lug currently used on the smaller Clems and all MIT fully-lugged bikes.

--
You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group.

To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owne...@googlegroups.com.

To view this discussion on the web visit https://urldefense.proofpoint.com/v2/url?u=https-3A__groups.google.com_d_msgid_rbw-2Downers-2Dbunch_ab572e71-2D3b22-2D4f3f-2Dae42-2De0bfbe0955b1-2540googlegroups.com&d=DwIFaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=fbpz-LhLhQnqxV9ePfEuoQ&m=zdOnZkL4-imZ2uJ9jNdVckdW6eHIum54VBbtRYEfZX4&s=IC6ULtQUHCeB8oelCIAYrk-8wx3ClbewZBhUNk-l_gQ&e=.

--
You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group.

To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owne...@googlegroups.com.

[Joe Bernard]

I suspect "modern standards" would be just as bewildering to me as Riv standards are to you. I've gone through stacks of 26.8 and 27.2 posts over many years and have never had trouble finding all the new and used ones I needed. For big fun try getting into folding bikes and figuring out THOSE sizes!

[Kainalu V. -Brooklyn NY]

I use a s-84 27.2 lugged post on my 29.8 Clem no problem! I used a shim which I filed to fit the contours of the seat lug. Never slipped, and looked even better to my eye. As for my 26.8 Roscos, nitto makes the s-83.
-Kai

[Adam in Indiana]

My Sam used a 26.8 seatpost, but this hadn't been updated on the website at the time of purchase, so it was a surprise...and I wasn't able to use my Nitto I had on hand. Somewhat annoying, but at least I had the provided Kalloy post.

My Sam also had beefed-up fork blades, but this was a design change only revealed after pre-order deposits had been made.

Overall, I'm not fond of Grant's/Rivendell's penchant for continually beefing up their frames here and there. Is there a real need for a .9 wall on the seat tube for a road bike..? Are there constant seat tube failures out there on road bikes with 27.2 posts that we're not hearing about?

But anyways, Origin8 also makes a 26.8 seatpost for around $28, and it's a two-bolt straight design that looks to be a copy of Thomson's.

[Joe Bernard]

I presume Sam's got beefier as they morphed to more of a street/trail vibe with canti posts in anticipation of the otherwise very similar Homer becoming a MIT bike.