26.8??

[Russ Baxter]

I thought most road bikes took 27.2 seatposts. Is 26.8 also a common size?

[Pete Biggs]

"Russ Baxter" <rwb...@yahoo.com> wrote in message
news:c00af3.020802...@posting.google.com...

> I thought most road bikes took 27.2 seatposts.

Most do now.

> Is 26.8 also a common size?

Not so common, but not exactly rare.

If you're having trouble finding a good 26.8 post, consider getting a 25.0
and shimming it. That will increase your options.

~PB

[Jeff Wills]

"Pete Biggs" wrote in message

> > I thought most road bikes took 27.2 seatposts.
>
> Most do now.
>
> > Is 26.8 also a common size?
>
> Not so common, but not exactly rare.
>

IIRC- (pauses while dusting off fuzzy, foggy, dusty memories) 26.8mm
seatposts were *generally* used on bikes built with straight guage
seat tubes while 27.2mm *usually* meant the seat tube was
single-butted. Thus, a better-quality, butted tube set would take the
27.2mm seat post.

Of course, with the advent of oversize tubes, alternate materials, and
general going-to-heck-in-a-handbasket, seatpost sizes are mostly
meaningless.

Jeff

[John Carrier]

Columbus SP seat tube requirement (then again it might have been standard
27.2)? Not sure on this one.

R / John

"Russ Baxter" <rwb...@yahoo.com> wrote in message
news:c00af3.020802...@posting.google.com...

[EdDyMeRkX]

I need to clear up some misconceptions on the tubing using 26.8 mm seatposts.
Columbus (SL, SP, SLX, etc.) and Reynolds seat tubes are single butted
(.7/.9mm), with the thicker end being at the bottom bracket. Tange, Champion,
and Ishiwotta (spelling?) are double butted (.9/.7/.9) and therefore .4mm
thicker at the top (.2mm on each side of the diameter). The euro tubesets feel
the the seatpost reinforces the tube in this area and the extra material is not
needed. These are all excellent tubesets and this is of little difference.
The brazing of the frameset is much more important. Older Columbus Aelle
tubesets ('70's) were straight gauge (.9mm) and used the 26.8 mm post also. So
in short, if the frame is made in europe and uses a 26.8 mm seatpost then it is
straight gauge. If it is Jap double butted then it also uses 26.8 mm although
it could be straight gauge if the decal doesn't say "double butted" but only
"Tange chrom-moly tubing " for example. Confused? If you like the ride don't
worry about the tubing.

[Paul Southworth]

In article <20020803125424...@mb-fk.aol.com>,

EdDyMeRkX <eddy...@aol.com> wrote:
>I need to clear up some misconceptions on the tubing using 26.8 mm seatposts.
>Columbus (SL, SP, SLX, etc.) and Reynolds seat tubes are single butted
>(.7/.9mm),
> with the thicker end being at the bottom bracket. Tange, Champion,
>and Ishiwotta (spelling?) are double butted (.9/.7/.9) and therefore .4mm
>thicker at the top (.2mm on each side of the diameter).

I think your dimensions are off. For one thing SL, SP, and SLX do not
all have the same wall thickness, and there are numerous variations
Tange and Ishiwata models as well, some of which have multiple butts
in the seat tube and some which do not.

SL seat tube is .5/.7
SLX is .6/.9
SP is .7/1.0
Ishiwata 022 is .6/.9 and no butt at the top
Reynolds 531C is .5/.8
Reynolds 501 is .6/.9

There are a few different Tange Champion tubesets as well, and they
don't all have a butt at the top either. Tange Prestige was available
with multiple butts in the seat tube, both at the bottom.

There are sometimes other variations even in a given make/model
based on the year it was produced or based on size of frame the
tube set is intended for (eg, large sizes sometimes had tube sets
adulterated with a few thicker bits from another tube set, SL+SP
being a popular one). Makes it a little harder to guess what is
actually in a given frame unless you really know what went into it,
can't always trust the sticker...

--Paul

[TW406]

I've had a few older English frames, double butted 531 that were 26.8.

[A Muzi]

"Russ Baxter" <rwb...@yahoo.com> wrote in message
news:c00af3.020802...@posting.google.com...

> I thought most road bikes took 27.2 seatposts. Is 26.8 also a common
size?

In traditional steel bikes with premium tubing, a single-butted deat tube is
27.2. A double-butted seat tube is 26.8. Alternates include 27.4 for a
light gauge single-butted tube and 27.0 for a heavy gauge single-butted
tube.

In today's alternate materials and with today's wanton disregard for
"standard" outside diameters, anything goes. There's no particular reason
for, say, an aluminum tube to be any particular size except at the whim of
the designer.

As an aside, plenty of $300 aluminum mountain bikes use 27.2 as well so you
should not infer a lot from a seatpost size any longer.
--
Andrew Muzi
http://www.yellowjersey.org
Open every day since 1 April 1971