1 1/8" handlebar stem - what's 1 1/8"?

Alan Paterson said:

I'm trying to adapt a bike for my daughter, by replacing the
handlebar stem to reduce the reach. The one on the bike is 20mm in
diameter, but all the ones I see listed seem to be 1 1/8". How do you
actually measure a handlebar stem? (The one on my 'regular' bike is
also 20mm, so???)

I can only assume you are measuring the diameter where the stem enters
the head tube. From the sizes you're talking about, your stem is likely
to be this type:
http://www.edinburgh-bicycle.co.uk/resource/sizing/quill_stem_adjust.jpg

rather than this type:
http://www.mountain-tamers.co.uk/trolleyed/images/products/t_2HSRD25.jpeg
(silly picture, but I hope it shows the difference)

1 1/8 stems are of the second "ahead stem" type (in general) whereas
what you most likely want is the first type, which is known as a "quill
stem".

22.2mm is the most common size of quill stem on adult bikes, but there
are other sizes, especially on foreign or children's bikes. The
measurement is the diameter of the stem.

There is also a difference in size depending on what sort of handlebars
are on the bike - in general, flat bars tend to be 25.4mm, and drop bars
26mm, but again there can be non standard sizes.

Quoted message said:

Thanks for all advice.

No problem.

JimP
--
Let's think the unthinkable, let's do the undoable, let's prepare to
grapple with the ineffable itself, and see if we may not eff it after
all. - DNA

Alan Paterson said:

I'm trying to adapt a bike for my daughter, by replacing the handlebar stem
to reduce the reach. The one on the bike is 20mm in diameter, but all the
ones I see listed seem to be 1 1/8". How do you actually measure a handlebar
stem? (The one on my 'regular' bike is also 20mm, so???)

Thanks for all advice.

The 1 1/8th refers to the diameter of the steerer tube usually. This is
for a threadless design. You might have a quill stem that slides inside
the steerer tube rather than wrap around the outside. You need to
replace like with like, you also need to ensure the clamp size matches
the diameter of the centre of the handlebar, this is usually given in
mm, often 26.0 or 25.8. The other dimension is of course the lenght.

in message <[email hidden]>, Alan Paterson

(') said:

I'm trying to adapt a bike for my daughter, by replacing the handlebar
stem to reduce the reach. The one on the bike is 20mm in diameter, but
all the ones I see listed seem to be 1 1/8". How do you actually
measure a handlebar stem? (The one on my 'regular' bike is also 20mm,
so???)

1 1/8" is the outside diameter of the steerer tube, and the only sizes
that have been available in the last thirty or so years are one inch
(now rare), one and an eighth inch, and one and a half inch (Cannondales
and downhill bikes only)[1].

Handlebars are available in three (main) different diameters. Mountain
bike type handlebars are 1" diameter at the clamp; road bike type
handlebars are 26mm diameter. Lately, both types have become available
in 'oversize' fitting, which means they bulge in the centre where the
clamp attaches to 31.8mm.

Your stem needs to be right for the steerer, right for the bars, the
right reach, and the right amount of rise. A good local bike shop will
really help here.

[1] According to Sheldon there are also 26mm, 28mm and 1 1/4" steerers
out there, but I've never seen 'em.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

Anagram: I'm soon broke.

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Quoted message said:

1 1/8" is the outside diameter of the steerer tube, and the only sizes
that have been available in the last thirty or so years are one inch
(now rare), one and an eighth inch, and one and a half inch (Cannondales
and downhill bikes only)[1].

[1] According to Sheldon there are also 26mm, 28mm and 1 1/4" steerers
out there, but I've never seen 'em.

Santana tandems still use 1 1/4" steerers, and it wasn't an unknown size for
other bikes - one of our Cannondales is 1 1/4". It's got reducers to get it
to 1 1/8" to fit a bouncy fork, and the bike shop had them in stock, which
suggests that it's not as rare as you think.

And 1 inch isn't that rare, and only has only stopped being the norm on road
bikes in the past couple of years - it'll almost certainly be what the OP's
got.

cheers,
clive

In article said:

1 1/8 stems are of the second "ahead stem" type (in general) whereas
what you most likely want is the first type, which is known as a "quill
stem".

Newer stems are more likely to be "ahead stem" type and more likely
to be 1 1/8, but 1 1/8 quill stems aren't that uncommon.