# Inseam Measurement?

Discussion in 'Cycling Equipment' started by Tom, Jun 3, 2003.

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1. ### Tom Guest

What is the correct way to measure the inseam?

I stood barefoot with my feet about 10" apart. AND if I used a broom stick and bring it up 'firm'
against the crotch, it measures 87.63 cm. BUT, if I take a metal ruler "edgewise" and force it up
against the 'pubic bone' it measures 90.00 cm. That's almost a full inch difference in inseam
measurement.

Which measurement should I use in determining bike size computations?

Tom

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2. ### Ken Guest

"Tom" <[email protected]> wrote in news:[email protected]:
> I stood barefoot with my feet about 10" apart. AND if I used a broom stick and bring it up 'firm'
> against the crotch, it measures 87.63 cm. BUT, if I take a metal ruler "edgewise" and force it up
> against the 'pubic bone' it measures 90.00 cm. That's almost a full inch difference in inseam
> measurement.

apart, how far up your leg would like the top tube to rise before it stopped?

3. ### Qui Si Parla Ca Guest

tom-<< Which measurement should I use in determining bike size computations?

Femur length, not inseam. Femur length will determine proper seat tube ANGLE and then your upper
body/arms will determine proper top tube :ENGTH and stem length. Inseam or standover means little.
If the seattube angle and top tube length is proper, the standover will take care of itself.

Sizing that uses inseam is incomplete at best. For instance, two riders have the same inseam but one
has long femurs. Long femur person cannot ride a 58cm Colnago(steep seat tube, cannot get the saddle
back far enough)) whereas the other guy can...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

4. ### Harris Guest

Tom <[email protected]> wrote:

> I stood barefoot with my feet about 10" apart. AND if I used a broom stick and bring it up 'firm'
> against the crotch, it measures 87.63 cm. BUT, if I take a metal ruler "edgewise" and force it up
> against the 'pubic bone' it measures 90.00 cm.

Ouch!

> Which measurement should I use in determining bike size computations?

The classic way of doing it is to use a hard cover book. With one edge of the book pressed against
the wall the other edge is made parallel to the ground. Mark the spot on the wall with a pencil
and measure.

Art Harris

5. ### Jason Wright Guest

So how do you measure your femur length without an X-ray?

Curious

JW

"Qui si parla Campagnolo" <[email protected]> wrote in message
news:[email protected]...
> tom-<< Which measurement should I use in determining bike size
computations?
>
> Femur length, not inseam. Femur length will determine proper seat tube
ANGLE
> and then your upper body/arms will determine proper top tube :ENGTH and
stem
> length. Inseam or standover means little. If the seattube angle and top
tube
> length is proper, the standover will take care of itself.
>
> Sizing that uses inseam is incomplete at best. For instance, two riders
have
> the same inseam but one has long femurs. Long femur person cannot ride a
58cm
> Colnago(steep seat tube, cannot get the saddle back far enough)) whereas
the
> other guy can...
>
>
> Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
> (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

7. ### Stu Guest

>>Here's one way:

>>http://www.rivendellbicycles.com/html/bikes_framesize.html

>surface with your feet 10-inches apart, and measure between your legs (the tape measure >should be
right in the middle) from the floor to your pubic bone. Not your genitals. Hit the >bone. Figure out
how to do this using a thin, hardcover book and a metal tape.

>example: If you are 5 feet 9 1/2, your pubic bone might be 85cm. Your

>Once you've determined your saddle height, you have a simple subtraction to
determine a >good frame size. "A good frame size" doesn't mean it's the only size for you. The whole
>purpose of sizing is too give you a comfortable riding position, and for most people that >means
getting the bars level with, or within a couple centimeters, of the saddle height. The >lower the
number you subtract, the higher the bars can be. In France or England in the
>'40s, you'd subtract about 15cm. In the case above, that would have that
5-foot 9 1/2 >inch rider on a 60cm frame.

They were doing great Right up to the part where they tell you how to measure your pubic bone
height. wall, book, tape, to easy Then they go straight from that to talking about saddle height,
miss something?? or do you just take off 10cm like in there example? thanks stuart

8. ### Tom Guest

They just recommend taking off 10cm, although its not very clear Tom "stu" <[email protected]> wrote in
message news:[email protected]...
> >>Here's one way:
>
> >>http://www.rivendellbicycles.com/html/bikes_framesize.html
>
height,
> >surface with your feet 10-inches apart, and
measure
> between your legs (the tape measure >should be right in the middle) from
the
> floor to your pubic bone. Not your genitals. Hit the >bone. Figure out how to do this using a
> thin, hardcover book and a metal tape.
>
>
> >example: If you are 5 feet 9 1/2, your pubic bone might be 85cm. Your
>
> >Once you've determined your saddle height, you have a simple subtraction
to
> determine a >good frame size. "A good frame size" doesn't mean it's the
only
> size for you. The whole >purpose of sizing is too give you a comfortable riding position, and for
> most people that >means getting the bars level with, or within a couple centimeters, of the saddle
> height. The >lower the number you subtract, the higher the bars can be. In France or England in
the
> >'40s, you'd subtract about 15cm. In the case above, that would have that
> 5-foot 9 1/2 >inch rider on a 60cm frame.
>
> They were doing great Right up to the part where they tell you how to measure your pubic bone
> height. wall, book, tape, to easy Then they go straight from that to talking about saddle height,
> l miss something?? or do you just take off 10cm like in there example? thanks stuart
>
>

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9. ### Chris Zacho "Th Guest

"Femur length, not inseam. Femur length will determine proper seat tube ANGLE and then your upper
body/arms will determine proper top tube :LENGTH and stem length. Inseam or stand over means little.
If the seattube angle and top tube length is proper, the standover will take care of itself.

Sizing that uses inseam is incomplete at best. For instance, two riders have the same inseam but one
has long femurs. Long femur person cannot ride a 58cm Colnago(steep seat tube, cannot get the saddle
back far enough)) whereas the other guy can...

Peter Chisholm"

So what's the poor guy supposed to do with that? It may be more accurate, but how's he supposed to
measure his leg bones? Take them out? LOL!

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

Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner

10. ### Qui Si Parla Ca Guest

Chris-<< So what's the poor guy supposed to do with that? It may be more accurate, but how's he
supposed to measure his leg bones? Take them out? LOL!

Nope, go to somebody that has a fit cycle and sit on that to determine proper seattube angle..not
rocket surgery or brain science..

Inseam measurements only to determine frameset size(standover and crotch distance test)can be wildly
inaccurate.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"