Difference between mountain and road threadless stems?



R

Res09c5t

Guest
Hi, 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? 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?

I'm looking for something that provides the extra rise that
some mountain stems provide.

Thanks! Lyle
 
res09c5t wrote:

> 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.

> 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 +-----------------------------------------------+
| I’m 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
 
<snip>
>It's basically marketing.

>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 wrote:

> 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.

> 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.

> 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
| 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 <[email protected]> wrote:
> 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" <[email protected]> wrote:
> 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 protected] (Chris
Zacho "The Wheelman") wrote:
>>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
 
> > They are now doing 31.8mm dia clamps which are indicated
> > as oversized.

"Sheldon Brown" <[email protected]> wrote:

> a.k.a. 1 1/8"

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

:eek:/

James Thomson
 
Sheldon Brown <[email protected]> wrote in message news:<[email protected]>...
> res09c5t wrote:
>
> > 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 protected]> wrote in message
news:<[email protected]>... <SNIP>
>
> > 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
 

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