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 Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

<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
http://www.geocities.com/czcorner

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.

a.k.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 http://web.mit.edu/gsp/www |
| http://sheldonbrown.com/music.html |
| Photos: http://sheldonbrown.org/g-s/thespis |
+-----------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

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.
Q: 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:
http://web.uni.com/stampa/articoli_2003/mount_bicycles.pdf

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