Difference between mountain and road threadless stems?

res09c5t said:

I've been looking at some of the catalogs and see that the
threadless stems are differentiated as road or mountain
stems. Is there any real difference?

It's basically marketing.

Quoted message said:

I'm only familiar with the road world. The steerer should
be a standard 1" or 1 1/8". Are the bars generally 26.0 on
the mountain stems?

No, most bars are ISO standard size, 1" (25.4 mm) but many
drop bars are the Italian 26.0 size.

Two bolt "pop-top" stems are pretty forgiving about this,
and can generally be interchanged between the two standars.

Sheldon "Stems Don't Care What Kind Of Surface You Ride On"
Brown +-----------------------------------------------+
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+-----------------------------------------------+ Harris
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<snip>

Quoted message said:

It's basically marketing.

Quoted message said:

Sheldon "Stems Don't Care What Kind Of Surface You Ride
On" Brown

</snip>

Actually, Mr. Brown, there may be a difference. I'm just
guessing, but wouldn't a stem designed for off road use
need to be more rugged? and since it doesn't need the
extra toughness, wouldn't a road stem favor lightness
over strength?

Or am I once again imagining a perfect world that cannot
possibly exist in reality? ;-3)

- -

"May you have the wind at your back. And a really low gear
for the hills!"

Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

Chris'Z Corner geocities.comczcornerOpen ↗

Hi if I am not mistaken.... MTB stem clamps are 25.4mm dia. Roadbike quill stems used to be the same but when changed to threadless system went to a 26.0mm dia. clamp. They are now doing 31.8mm dia clamps which are indicated as oversized.

Regarding marketing BS or not, I don't want to comment. Regarding ISO standards, I don't know how to comment.

Regards,
Sean

An anonymous poster said:

Hi if I am not mistaken.... MTB stem clamps are
25.4mm dia.=20

Yes, that is the ISO standard size for all types of
bicycles, a.k.a. 1 in=
ch.

Quoted message said:

Roadbike quill stems used to be the same but when changed
to threadless system went to a 26.0mm dia. clamp.=20

No, there's no connection with threadless, that has to do
with the other =

end of the stem, the way it fits on the fork.

Both quill and threadless stems are readily available in
both 25.4 and=20 26 mm sizes. The selection is much better,
however, in the ISO=20 standard 25.4 size.

Before the ISO standards were promulgated, there were a
variety of=20 national sizes for handlebar/stem clamps, and
also some proprietary ones =

used by specific manufacturers (Cinelli, Titan.)

Because some Italian brands of stems and handlebars were
popular for=20 high-end road bikes, the Italian 26.0 mm
standard is often used as a=20 secondary size standard for
drop handlebars, but most drop bars on the=20 road are
actually 25.4.

Quoted message said:

They are now doing 31.8mm dia clamps which are indicated
as oversized.

c.h.a. 1 1/8"

Sheldon "Can't Kill Inch-based Standards" Brown +-----------------------------------------------
+
| I=92m appearing as Preposteros in | Gilbert &
| Sullivan's Thespis at M.I.T. | April 9-10,15-17
| web.mit.eduwwwOpen ↗ |
| sheldonbrown.commusic.htmlOpen ↗ | Photos: sheldonbrown.orggOpen ↗
| s/thespis |
+-----------------------------------------------+ Harris
Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX
617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗
sheldonbrown.comsheldonbrown.comOpen ↗

Sheldon Brown said:

Because some Italian brands of stems and handlebars were
popular for high-end road bikes, the Italian 26.0 mm
standard is often used as a secondary size standard for
drop handlebars, but most drop bars on the road are
actually 25.4.

Is that really the case in the US? At least here in
continental Europe 25,4m is not common for drop bars.

--
MfG/Best regards helmut springer

Chris Zacho 'The Wheelman said:

Actually, Mr. Brown, there may be a difference. I'm just
guessing, but wouldn't a stem designed for off road use
need to be more rugged? and since it doesn't need the
extra toughness, wouldn't a

Visualize the road cyclist climbing and sprinting hard,
hitting a pothole at hight speed with high pressure tires
from time to time.

--
MfG/Best regards helmut springer

On Sat, 17 Apr 2004 10:52:25 -0400, [email hidden] (Chris

Zacho 'The Wheelman') said:

Quoted message said:

It's basically marketing. Sheldon "Stems Don't Care What
Kind Of Surface You Ride On" Brown

Actually, Mr. Brown, there may be a difference. I'm just
guessing, but wouldn't a stem designed for off road use
need to be more rugged? and since it doesn't need the extra
toughness, wouldn't a road stem favor lightness over
strength?

According to Nashbar (see below), that's all true; but it
doesn't make Sheldon wrong. The stem still doesn't care, and
the issue is still _basically_ marketing. There's a little
bit of weight savings: Easton EA70XC off-road stem: 135gm
Easton EA70 road stem: 130gm Same manufacturer, on and off
road variation of same model, 5 gram difference.

$20 ITM road stem: 193gm (120mm) $20 Nashbar off-road stem:
178gm (105mm) Given the length difference, probably almost
exactly the same at equal length.
--
Rick Onanian

Quoted message said:

Quoted message said:

They are now doing 31.8mm dia clamps which are indicated
as oversized.

Sheldon Brown said:

a.k.a. 1 1/8"

Trust an American fraction to be twice the size of a
British one.

:o/

James Thomson

Sheldon Brown <[email hidden]> wrote in message
[email hidden]

[...]

Quoted message said:

Sheldon "Can't Kill Inch-based Standards" Brown

Yes, even when it sounds longer in metric.

--

A: Top-posters.
B: What is the most annoying thing on Usenet?

Sheldon Brown <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

res09c5t said:

I've been looking at some of the catalogs and see that
the threadless stems are differentiated as road or
mountain stems. Is there any real difference?

It's basically marketing.

Sheldon "Stems Don't Care What Kind Of Surface You Ride
On" Brown

There are different test standards for racing and mountain
bikes, and the loads differ. Whether the stems we buy are
actually different in practice I don't know.

Here's one mountain standard:
web.uni.commount bicycles.pdfOpen ↗

Maybe someone can find the racing bike standard, I couldn't.

Sheldon Brown <[email hidden]> wrote in message
news:<[email hidden]>... <SNIP>

Quoted message said:

Quoted message said:

They are now doing 31.8mm dia clamps which are indicated
as oversized.

a.k.a. 1 1/8"

1 1/8" is about 28.6mm, not 31.8mm.

31.8mm is much closer to 1 1/4".

Ed