A Bit Irked that Riv Changed the Seatpost Size

[David Person]

I sure wish Riv hadn't changed the seat post diameter from 27.2mm to 26.8mm on their frames. Doing so really limits the available seat post options.  One particular suspension seat post I use is only available in 27.2mm.  Baffles me why Riv chose to do that.  Glad I got my Hillborne before the change, but rules out an Appaloosa as my next bike.

[Mark Schneider]

I wonder why, I guess I missed that one. Someone more knowledgeable probably knows why, something to do with available tubing maybe?

[Joe Bernard]

Or available lugs. I don't know how any of this works but all the new Riv frames with a regular high tobtube (diamond frame) get the same seat lug now, I suspect it has something to do with the narrower diameter seattube. 

Joe Bernard

[christian poppell]

It would be a seat tube change and not the lug. Many tubes for are butted internally so that lugs will fit multiple tube butt thicknesses. 

28.6mm x .9mm wall (26.8mm ID) vs .7mm (27.2mm ID). 

Christian

Berkeley, CA

[David Person]

Sure is a shame.  

[Kainalu V. -Brooklyn NY]

The S83 comes in 26.8, and if you need a better seatpost than that, well then maybe you do, who am I to say. For me, it's as good as good gets, and I've got an 84 to compare it to! (in 27.2, which I use with a shim on my Clem that has a 665.5* seattube)

-Kai

*not quite evil, but very close, certainly not as bad as 26.8

[Benz Ouyang, Sunnyvale, CA]

On Tuesday, November 24, 2020 at 6:01:18 PM UTC-8 christian poppell wrote:

It would be a seat tube change and not the lug. Many tubes for are butted internally so that lugs will fit multiple tube butt thicknesses. 

28.6mm x .9mm wall (26.8mm ID) vs .7mm (27.2mm ID). 

Does that mean one can ream it out to 27.2mm if one has the proper reamer?

FWIW, 26.8mm isn't that common anymore. I had to find one for a NOS Ritchey P-21 frame that a friend gifted me, and it was either some el cheapo thing, or pay through the nose for a NOS or like-new seatpost from the 90s. Yes, there are Thomsons and Nittos, but the Nittos are usually too short (because they're intended for road bikes), and the Thomsons are…well, if you have to ask why a Thomson doesn't belong on a Ritchey P-21…

[Benz Ouyang, Sunnyvale, CA]

On Tuesday, November 24, 2020 at 7:38:51 PM UTC-8 Kainalu V. -Brooklyn NY wrote:

The S83 comes in 26.8, and if you need a better seatpost than that, well then maybe you do, who am I to say. For me, it's as good as good gets, and I've got an 84 to compare it to! (in 27.2, which I use with a shim on my Clem that has a 665.5* seattube)

While what you said about the Nitto S83 is arguably true, the OP was lamenting that he couldn't use a suspension seatpost he likes that is only available in the much more common 27.2mm size. No S83 is going to replace a suspension seatpost if a suspension seatpost is what you want.

Nevertheless, vintage U.S.E. suspension seatposts do occasionally become available on eBay. I don't know if those are adequate replacements though.

[The Snag]

Yes. It was quite the chore to put a dropper post on my Mtn mixte. Funny how that .4mm makes such a difference in options.....

[David Person]

Benz, you get my point.  A lumbar fusion has made a suspension seat post almost a necessity.

On Tuesday, November 24, 2020 at 8:38:12 PM UTC-8 Benz Ouyang, Sunnyvale, CA wrote:

[Mark Roland]

Maybe you could find someone to make you a custom seat post, perhaps using the suspension model you like as a starting point. There's these guys: https://kenteriksen.com/seatposts/  and looks like a few that use titanium. Probably will be pricey, but worth it I'm sure for a last forever bike like a Rivendell.

[Garth]

There's these David, Gravity makes dropper posts, 26.8.

http://gravitydropper.com/products/

There's also the classic Hite-Rites

https://www.ebay.com/itm/Vintage-HITE-RITE-Saddle-Dropper-New-Sealed-In-Package-/183231146016

No bounds !

[Kainalu V. -Brooklyn NY]

Oops!, my love for the s83 narrowed my focus, sorry. Cane Creek's thudbuster come in a 26.8, I hear them mentioned a lot in tandem talk, are they a decent post?

-Kai

On Wednesday, November 25, 2020 at 1:23:05 AM UTC-5 David Person wrote:

[lconley]

My Bombadil was 27.0 - I used a brake cylinder hone to take it out to 27.15 or so, so that a 27.2 Nitto S-84 lugged seatpost would fit. On a side note, my Guv'nor is also a 27.0.

My Rivendell Custom was 30.0 - I had never even heard of that size (31.8 tube OD, 0.9 thick) - The only quality seatpost that I could find was an NOS Campagnolo Icarus - which is nice, but only single bolt design. I am not big on using seatpost shims.

Nitto makes long S-83s and S-84s, but Rivendell does not sell them. I have 300mm versions of both, I think that I saw a 350mm S-83 for sale once.

Laing

On Tuesday, November 24, 2020 at 6:55:20 PM UTC-5 David Person wrote:

[Ben Mihovk]

Not to veer too far off topic...but model what is the stock build seat post that comes with a Riv frame? I don’t think it’s even Nitto at all (or is it?)...and wondering what upgrading to s83 or even just the s65.

Ben

Sent from my iPhone

On Nov 25, 2020, at 7:07 AM, lconley <lco...@brph.com> wrote:

My Bombadil was 27.0 - I used a brake cylinder hone to take it out to 27.15 or so, so that a 27.2 Nitto S-84 lugged seatpost would fit. On a side note, my Guv'nor is also a 27.0.

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[Mark Schneider]

I'd prefer 27.2 but there are plenty of options for 26.8,  prefer thinner tubing mostly.

Mark

[David Person]

27.2mm is smallest diameter on the current Thudbuster models.

[Philip Williamson]

Mr The Snag, I am very interested in seeing your mountain mixte with the dropper post. I think droppers are better than bread; it’s a shame Rivendell specs pinner seat posts.

Philip

Santa Rosa, CA

[Nathan F]

I was also disappointed to learn my Hillborne used a 26.8. What a frustrating choice, since seat post diameter is one of the few things in the bicycling industry that is almost standard nowadays (ignoring the sizes in use on modern MTB, plus all the proprietary crap). Then here comes Riv using something else! And instead of picking a size with some sort of tangible benefit, they picked a seemingly random one used infrequently 3+ decades ago. It's a bit eye-rolling, really, for all of Riv's talk over the years bemoaning the fickleness of the industry they then spec the strangest, most hard to find post diameters (30.0 on a custom?? Really? I'd return it!).

Here's a controversial statement: being the only frame manufacturer using a dead/rare post size is almost no different than using a proprietary seat post. 

[Joe Bernard]

I would argue that ignoring modern MTBs and "all the proprietary crap" is a long way from establishing there is a standard seatpost size in the bicycle industry. 

[Nathan F]

I didn't try to establish there is a standard seatpost size, I said almost standard ; ) How about this phrasing: there are only a few sizes in broad use today and the most common one is 27.2.

Ignoring that part of what I said, my point still stands. Using weird old sizes like Riv does reduces options for customers and is a dumb idea!

[Eric Daume]

Modern mtbs have really coalesced around 30.9 or 31.6 seat posts. A few are bigger are smaller, but I’d guess 80% of new mountain bike have one of these two sizes. 

Eric

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[Nathan F]

Meanwhile .0004% of bicycles (Rivendell's contribution to the ~100,000,000 that are produced every year) come with 26.8 lol

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[Patrick Moore]

Isn't seatpost diameter dictated by tubing choice? That said, I agree that 26.8 is less desirable given supply than 27.2.

On Thu, Nov 26, 2020 at 10:19 AM Nathan F <nathan...@gmail.com> wrote:

I was also disappointed to learn my Hillborne used a 26.8. What a frustrating choice, since seat post diameter is one of the few things in the bicycling industry that is almost standard nowadays (ignoring the sizes in use on modern MTB, plus all the proprietary crap). Then here comes Riv using something else! And instead of picking a size with some sort of tangible benefit, they picked a seemingly random one used infrequently 3+ decades ago. It's a bit eye-rolling, really, for all of Riv's talk over the years bemoaning the fickleness of the industry they then spec the strangest, most hard to find post diameters (30.0 on a custom?? Really? I'd return it!).

Here's a controversial statement: being the only frame manufacturer using a dead/rare post size is almost no different than using a proprietary seat post. 

 

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Patrick Moore

Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum

[Mark Roland]

Yes. Tubing diameter and thickness generally dictates seat post size. In that sense, the sizing is part of its functionality. A 26.8 seat post size is not exactly unusual, and before 27.2 became dominant, was fairly common. I have several bikes, other than my recent Rivs, that use this size.

If you want a cheap but good one, you can get a Kalloy Uno.

If you want a middle range, you can get one from Dajia Cycleworks(note most sizes currently out of stock).

If you want blingy dingy doo, you can get a Nitto.

There are many vintage 26.8 seat posts available on eBay, including Campy (though these tend to often be short) .

Or use the seat post included with all Rivendell framesets.

Before we pile on too heavy, I don't see it as a dying, esoteric size at this point.

The OP wants to run a suspension post due to medical issues. Running a suspension post, which are of questionable value in my experience (but obviously not for the OP), is what is unusual, not the seat post size.

I think there are probably ways (though perhaps pricey) to have your cake and eat it too. For that you might need to go custom, as I pointed out above. Since Thudbuster makes specialty seat posts while Riv makes standard bicycles, it would make more sense to complain to TB and try to convince them there is a market for 26.8 suspension seat posts.

[Mark Roland]

Here are a bunch of 26.8 suspension posts on eBay right now. Should last a lifetime of Rivs!

[Garth]

Along with what Mark stated, 26.8mm seatposts are far from alien. I gave the link to the Gravity dropper posts, all 3 of their models come in 26.8 and they offer many options for the amount of travel.

Kalloy, which makes the Dajia/Soma, among many other re-brands, makes at least 3 totally different styles of posts currently in 26.8.

This 2 bolt one from SJS Cycles as the PRO brand appears to be a Kalloy SP-376. It's also made under the Euro brand Procraft from many German retailers.

https://www.sjscycles.co.uk/seat-posts/shimano-pro-aero-silver-alloy-seatpost-268-x-220-mm/?geoc=US

I may have bought one of these Promax ones if it had a bit more setback, and it comes in silver, black, blue, red and gold !

https://www.promaxcomponents.com/product/sp-1-seatpost/

[Brewster Fong]

The question I have is are these "suspension" post that you refer to the same a dropper post that he OP is seeking?!  The dropper post is the latest thing for gravel/mtbs as it allows you to adjust the saddle height with the press of a button. These posts aren't cheap a they start at like $200 and go up! I think Sram's wireless post is $800+

Good Luck!

[Brewster Fong]

My bad, the Op did ask about suspension posts. Someone else asked about dropper post. Still, it does make you wonder what Grant is thinking going to a 26.8mm seatpost on his frames?!

Good Luck!

[Nathan F]

We're basically just bickering at this point but I can't help myself... the suspension posts posted on eBay above are all awful compared to the market leading suspension posts from Cane Creek and the like. They're not even really the same thing from a functionality perspective. Linking to them is a total straw man. 

Cane Creek's design has been around for 20+ years, and is a well proven, tunable, and serviceable technology. Lots and lots of people love them and I suspect that's what OP was hoping to use.

[David Person]

Nathan, your spot on with your comment on the pogo stick seat posts selling on eBay for $25.  And actually, I'm not looking to buy another suspension seat post as I own 2 Kinekt seat posts in 27.2.  I use one on my Hillborne.  My angst is that I'd would have liked to get an Appaloosa frameset at some point, but not now that they take 26.8mm posts, which severely limits ones options, compared to what is available in 27.2.  

[Mark Roland]

Well, as I said above, I'm not an expert in suspension posts, so I haven't seen the testing labeling one or another brand far superior, one that many people love, and therefore rendering my point into a straw man. In 50 years of riding, with clubs, for transportation, being involved in many ways, I've never ridden with someone who purposely rode with a suspension post. Caveat--I am not a mountain biker so don't have a lot of experience in that world, though I understand there the whole bike is usually suspended. The ones I've come across in the wild were on hybrids, cheap mtbs, (now extinct ?) "comfort" bikes, and tandem stoker posts.

I guess my point was more if you really want a certain Riv model, you can probably find a way to get a seat post that will work for you. Maybe you could get .2mm milled off the post and .2 reamed out of the seat tube. Or just be thankful the Hillborne takes a 27.2 and call it a blessed day.

[Matthew Williams]

I would not recommend milling the inside of the seat tube. You'd be weakening the structure of the frame and the milling would be difficult and more expense than it's worth.

Instead, find a local fabricator and request the following:

1: Get a section of 27.2mm tubing and cut it to length (300mm or thereabouts)

2: Cut the tube from the seatpost you want

3: TIG-weld the 27.2mm tubing to the base of your seatpost

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[Mark Roland]

I think you mean get a section of 26.8 tubing. Yes, I suggested a custom based on his favorite seat post.

[Joe Bernard]

A custom would certainly do the trick. Mine was built to a spec similar to if you put the toptube lower on an Appaloosa, and it uses a 27.2 post. Solved! 

[David Person]

I think I'll buy a Surly Bridge Club frameset and save myself $3400 vs a custom.

[Joe Bernard]

This is another option. 

[scott minor]

Do MIT frames all take 26.8 seat posts?   Wondering specifically about the MIT Atlantis..

[Mark Roland]

And you could discuss that bike on the SOB* list!

*Surly Owners Bunch

[Eamon Nordquist]

I thought the MIT Homers use a 27.2 seatpost. I could be wrong - the description doesn’t say, as far as I can tell.

Eamon

Seattle  

[EricP]

Well, if it needs to be said (and it doesn't) I'm also not overly happy about the larger Clem using a 29.8 seatpost size. But in this case it's purely personal. Wanted a Thomson setback post in black for the bike and that is one size they only do straight. Ended up finding a used Uno in black on eBay. It does work, but it's not as nice as the Thomson.

Oh, and for those who wonder why do this? I'm fat and have found over the years that most anodized seatposts seem to slip less than regular silver versions. I also automatically replaced the stock bolt and nylock nut with a different bolt and regular nut so I can torque the lug tighter. Still doesn't totally stop slipping. But does slow it down to a reasonable level.

Eric Platt

St. Paul, MN

[velomann]

The Promax SP-1 comes in 26.8, and 4 colors (though not silver apparently). Nice 2-bolt design easy to fine tune the angle. I picked up a blue one and a gold one recently when 26.8 size was on sale for $10. The gold one is on my new Sam and matches nicely. 
Mike M

On Tuesday, November 24, 2020 at 3:55:20 PM UTC-8 David Person wrote:

I sure wish Riv hadn't changed the seat post diameter from 27.2mm to 26.8mm on their frames. Doing so really limits the available seat post options.  One particular suspension seat post I use is only available in 27.2mm.  Baffles me why Riv chose to do that.  Glad I got my Hillborne before the change, but rules out an Appaloosa as my next bike.

[Patrick Moore]

Eric: FWIW: I'm not very heavy, but I have experienced seatpost slippage with undersized seatposts, and I've cured them with 2 proprietary near-liquids: blue Loctite in the case of a Syncros ti seatpost, and that gel with roughish bits in it meant to be used with CF seatposts, this for the current (silver) Dura Ace 74?? on my recent Matthews, and the cheap (anodized) OEM on the current Monocog. I hear that Loctite even makes a solution meant for preventing slippage that's not the blue.

On Sun, Nov 29, 2020 at 6:42 AM EricP <eperic...@gmail.com> wrote:

Well, if it needs to be said (and it doesn't) I'm also not overly happy about the larger Clem using a 29.8 seatpost size. But in this case it's purely personal. Wanted a Thomson setback post in black for the bike and that is one size they only do straight. Ended up finding a used Uno in black on eBay. It does work, but it's not as nice as the Thomson.

Oh, and for those who wonder why do this? I'm fat and have found over the years that most anodized seatposts seem to slip less than regular silver versions. I also automatically replaced the stock bolt and nylock nut with a different bolt and regular nut so I can torque the lug tighter. Still doesn't totally stop slipping. But does slow it down to a reasonable level.

[EricP]

Patrick,

Thanks for the suggestion. Will look into that. Yes, it needs to be either an undersized post, or an oversized person on top for slippage to happen. Still haven't totally settled on the final saddle choice for the Clem, but for now am just going to keep using the factory stock model. Works for me on rides up to 20 miles so far. Once decided, might use the Locktite solution. 

Eric Platt

St. Paul, MN

[Patrick Moore]

You are very welcome. Note that neither the Loctite nor the "gel with roughage" solutions make it hard to remove the seatpost, only with Loctite you have to smear more on after you remove, because it dries out, while the gel seems not to dry out, at least, not as fast. So experiment and, if you don't like it, wipe clean.

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[lconley]

My 1st batch Clementine 52 uses a 29.8 seatpost. I am surprised that the use of varied seatpost diameters causes so much heartache here, but I rode French bikes in the seventies, which used different size seat tubes and top tubes than "normal", so I am used to having to look a little harder to find the components that I want - try finding French diameter front derailleurs. At least we have the internet and search engines now which makes it much, much easier - the 30.0 Campy Icarus seatpost on my custom came from Italy. It may not have been my 1st choice in seatpost, but now that I have it, I am rather fond of it's uniqueness - a good complement to my one of a kind Brooks B-678 saddle.

Note that honing out a seat tube 0.2 or 0.15 mm with a brake cylinder hone is not going to make a big difference in frame strength. You only have to hone enough to make the make the seatpost fit, and only as deep as necessary. if you only hone as much as necessary (a 27.2 seatpost isn't necessarily 27.2, it may be only 27.1 - 27.15), once bolted in, the seatpost is in contact with the frame and acts as an internal reinforcement. Current production Rivendell tubes are plenty thick. My 1st Sam H used a 27.2 seatpost which meant its tube thickness was thinner than my second Sam H that used a 26.8 seatpost (the outer diameter of the tubes is the same).

I honed out the 27.0 ID seat tube in my Bombadil to 27.1 or 27.15 or so, in order to get the Nitto 27.2 lugged setback seatpost to fit. I weigh ~280. No problems. Note that the Bombadil seatpost never, ever slips.

Laing

Delary Beach FL

[The Snag]

Philip, 

I bought a 27.2 KS Lev with 65mm of travel and sanded down the post until it fit snug in the 26.8 seat tube. I have zero safety concerns about shaving off .4mm, these things are made for extreme riding that I won't come close to. I briefly considered cutting off the pointy tip of the seat tube lug but I knew I'd regret it so I ended up carving out the collar on the post, which worked out just fine. I'm not a big fan of the majority of new MTB products but if anyone has a mountain/hilly bike and goes downhill on occasion, then that bike should have a dropper post.....

[Patrick Moore]

Slight tangent: Nice Clem mountain bike. What bar are you using?

On Mon, Nov 30, 2020 at 7:06 AM lconley <lco...@brph.com> wrote:

My 1st batch Clementine 52 uses a 29.8 seatpost....

[Kainalu V. -Brooklyn NY]

Rosco Dropper!

Very nice bicycle..

-Kai

[Philip Williamson]

That’s great, The Snag! I’m glad you didn’t file down the pointy seat lug. 

Philip

Santa Rosa, CA 

[Nick Payne]

The seattube on steel frames is 1-1/8" (28.6mm) external diameter. If the builder uses 0.7mm wall thickness for the seattube, that gives 27.2mm internal diameter; 0.9mm gives 26.8mm.

I found that the 26.8mm seatpost supplied with my Appaloosa was a slightly loose fit in the seattube, and as I already had a nice Suntour Superbe Pro post in 27.0, I reamed the seattube slightly to take that seatpost.

Nick

David Person

25 Nov

to RBW Owners Bunch

[Joe Shoemaker Music]

I’m with ya. I reeeally want to put the lugged nitto seatpost on my Appaloosa to match my lugged stem, because in vein and OCD about that stuff :), but it’s just not in the cards. Oh well 

On Thursday, November 26, 2020 at 10:24:06 AM UTC-8 Joe Bernard wrote:

I would argue that ignoring modern MTBs and "all the proprietary crap" is a long way from establishing there is a standard seatpost size in the bicycle industry. 

On Thursday, November 26, 2020 at 9:19:49 AM UTC-8 Nathan F wrote:

I was also disappointed to learn my Hillborne used a 26.8. What a frustrating choice, since seat post diameter is one of the few things in the bicycling industry that is almost standard nowadays (ignoring the sizes in use on modern MTB, plus all the proprietary crap). Then here comes Riv using something else! And instead of picking a size with some sort of tangible benefit, they picked a seemingly random one used infrequently 3+ decades ago. It's a bit eye-rolling, really, for all of Riv's talk over the years bemoaning the fickleness of the industry they then spec the strangest, most hard to find post diameters (30.0 on a custom?? Really? I'd return it!).

Here's a controversial statement: being the only frame manufacturer using a dead/rare post size is almost no different than using a proprietary seat post. 

On Wednesday, 25 November 2020 at 22:05:42 UTC-8 Philip Williamson wrote:

Mr The Snag, I am very interested in seeing your mountain mixte with the dropper post. I think droppers are better than bread; it’s a shame Rivendell specs pinner seat posts.

Philip

Santa Rosa, CA

On Tuesday, November 24, 2020 at 8:48:56 PM UTC-8 The Snag wrote:

Yes. It was quite the chore to put a dropper post on my Mtn mixte. Funny how that .4mm makes such a difference in options.....

On Tuesday, November 24, 2020 at 8:38:12 PM UTC-8 Benz Ouyang, Sunnyvale, CA wrote:

On Tuesday, November 24, 2020 at 7:38:51 PM UTC-8 Kainalu V. -Brooklyn NY wrote:

The S83 comes in 26.8, and if you need a better seatpost than that, well then maybe you do, who am I to say. For me, it's as good as good gets, and I've got an 84 to compare it to! (in 27.2, which I use with a shim on my Clem that has a 665.5* seattube)

While what you said about the Nitto S83 is arguably true, the OP was lamenting that he couldn't use a suspension seatpost he likes that is only available in the much more common 27.2mm size. No S83 is going to replace a suspension seatpost if a suspension seatpost is what you want.

Nevertheless, vintage U.S.E. suspension seatposts do occasionally become available on eBay. I don't know if those are adequate replacements though.

[david.h....@gmail.com]

I can confirm that my MIT Atlantis uses a 26.8 mm seatpost. I don’t know if they all do though