how are stem lengths measured?

[Mike Lana]

Hi everyone, I need a longer stem on my bike. The only problem is, I don't know how long the current
one is. I know I need one about 10mm longer. Is the measurement taken from weld to weld? center to
center? I am also asuming that the fork size is the outer diamiter of the fork sticking out of the
head tube. Is this correct (1" or 1 1/8"). If anyone knows what came stock on my bike this might be
easy. 2000 speacialized m4 with a profile featherlight fork. Thanks Mike please respond to this
group or [email protected]

 

[GearóId Ó Laoi]

Send away for this penis enlargement stuff that's all over everyone's emails and rub it on it. It
might work for that if works on all of these undersized manstems!

 

[Michael Dart]

"Mike Lana" <[email protected]> wrote in message
news:[email protected]...
> Hi everyone, I need a longer stem on my bike. The only problem is, I don't know how long the
> current one is. I know I need one about 10mm longer. Is the measurement taken from weld to weld?
> center to center? I am also asuming that the fork size is the outer diamiter of the fork sticking
> out of the head tube. Is this correct (1" or 1 1/8"). If anyone knows what came stock on my bike
> this might be easy. 2000 speacialized m4 with a profile featherlight fork. Thanks Mike please
> respond to this group or [email protected]

You measure stem length from the center of the steerer to the center of the handlebar. Size 1" or
11/8" refers to the steerer tube diameter. This tidbit of info isn't readily found anywhere that I
could find and I had to ask the same question once. Thought I'd pass on the favor.

Mike

 

[Randomchris]

Michael Dart <[email protected]> wrote in message news:[email protected]...
>
> "Mike Lana" <[email protected]> wrote in message
> news:[email protected]...
> > Hi everyone, I need a longer stem on my bike. The only problem is, I don't know how long the
> > current one is. I know I need one about 10mm longer. Is the measurement taken from weld to weld?
> > center to center? I am also asuming that the fork size is the outer diamiter of the fork
> > sticking out of the head tube. Is this correct (1" or 1 1/8"). If anyone knows what came stock
> > on my bike this might be easy. 2000 speacialized m4 with a profile featherlight fork. Thanks
> > Mike please respond to this group or [email protected]
>
> You measure stem length from the center of the steerer to the center of
the
> handlebar. Size 1" or 11/8" refers to the steerer tube diameter. This tidbit of info isn't
> readily found anywhere that I could find and I had to ask the same question once. Thought I'd
> pass on the favor.
>
> Mike
>
>

Just to add confusion, I borrowed an ITM Millenium stem that clearly said 110mm on it, yet when I
measured it centre-centre it was clearly 105mm

WRT other measurements, I've also been stung a couple of times with (road) bar widths. Some places
seem to quote emasurements outside-outside whereas others quote centre-centre. I had some ITM 44s
that were no wider than my Cinelli 42s and some Profile 42s that were wider than both! Anyone know
the 'correct' way?

In short, if you can, check what you're buying against you're existing set-up.

 

[Pete Biggs]

RandomChris wrote:
> Just to add confusion, I borrowed an ITM Millenium stem that clearly said 110mm on it, yet when I
> measured it centre-centre it was clearly 105mm

Anyone know if that applies to the ITM Big One stem as well?

> WRT other measurements, I've also been stung a couple of times with (road) bar widths. Some places
> seem to quote emasurements outside-outside whereas others quote centre-centre. I had some ITM 44s
> that were no wider than my Cinelli 42s and some Profile 42s that were wider than both! Anyone know
> the 'correct' way?

It depends on the manufacturer. Cinelli's are measured c-c, most of the rest of modern bars are
measured outside to outside. Generally, o-o measurements are 2cm wider than c-c. I believe the
convention is to measure from bar end to bar end with drops.

~PB

 

[Mark Hickey]

"RandomChris" <[email protected]> wrote:

>Just to add confusion, I borrowed an ITM Millenium stem that clearly said 110mm on it, yet when I
>measured it centre-centre it was clearly 105mm

Perhaps they measure from the center of the clamp to the center of the BARS using a horizontal
reference. If the stem has any rise, that will "rotate the centerline forward" around the bars to
the highest point.

>WRT other measurements, I've also been stung a couple of times with (road) bar widths. Some places
>seem to quote emasurements outside-outside whereas others quote centre-centre. I had some ITM 44s
>that were no wider than my Cinelli 42s and some Profile 42s that were wider than both! Anyone know
>the 'correct' way?

Deda, TTT and ITM measure outside to outside. Everyone else measures center to center.

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame

 

[A Muzi]

> > "Mike Lana" <[email protected]> wrote in message
> > news:[email protected]...
> > > Hi everyone, I need a longer stem on my bike. The only problem is, I don't know how long the
> > > current one is. I know I need one about 10mm longer. Is the measurement taken from weld to
> > > weld? center to center? I am also asuming that the fork size is the outer diamiter of the fork
> > > sticking out of the head tube. Is this correct (1" or 1 1/8"). If anyone knows what came stock
> > > on my bike this might be easy. 2000 speacialized m4 with a profile featherlight fork.

> Michael Dart <[email protected]> wrote in message news:[email protected]...
> > You measure stem length from the center of the steerer to the center of
> the
> > handlebar. Size 1" or 11/8" refers to the steerer tube diameter. This tidbit of info isn't
> > readily found anywhere that I could find and I had
to
> > ask the same question once. Thought I'd pass on the favor.

"RandomChris" <[email protected]> wrote in message
news:[email protected]...
> Just to add confusion, I borrowed an ITM Millenium stem that clearly said 110mm on it, yet when I
> measured it centre-centre it was clearly 105mm
>
> WRT other measurements, I've also been stung a couple of times with (road) bar widths. Some places
> seem to quote emasurements outside-outside whereas others quote centre-centre. I had some ITM 44s
> that were no wider than my Cinelli 42s and some Profile 42s that were wider than both! Anyone know
the
> 'correct' way?
>
> In short, if you can, check what you're buying against you're existing set-up.

Just as we label frames both with center-to-center and also with center-to-top sizes, we note
handlebar widths in both formats. It is important for you to ask explicity when buying a handlebar
whether the measurement is taken normally on centers or in this new revisioninst
outside-to-outside way.

Stems are indeed measured on centers but notice that when laying a tape measure along the top you'll
frequently err my 5mm or so. Try measuring along the side.

Just as frames with sloping top tubes are now described with top tube both on centers and virtual
top tube - - the latter being the center-to-center measurement of a putative top tube if there were
a level one there to measure - - you might consider your stem length both actually and virtually. A
horizontal measurement with the effective reach is often a more useful number than the actual
sloping size of a stem.

Chris also makes a good point about actually holding the thing in your hand before buying. It's
simple at your LBS to let your current bar/stem/cables dangle off the edge of the bike while you try
the new setup in a trainer. Helps us to do it right the first time.
--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971