frame sizing

[Geraint Jones]

Are there any folk rules of thumb about the length of the frame, from say seat tube to headstock,
like the ones about leg length and seat tube or about clearance when straddling the crossbar?

(I know that the right way of fitting a bike to a person is to try it, but how can someone who has
never had a bike anything like small enough know that what it feels like is right?)

 

[Alex Graham]

On 19 Feb 2003, Geraint Jones wrote:

> Are there any folk rules of thumb about the length of the frame, from say seat tube to headstock,
> like the ones about leg length and seat tube or about clearance when straddling the crossbar?
>
> (I know that the right way of fitting a bike to a person is to try it, but how can someone who has
> never had a bike anything like small enough know that what it feels like is right?)

Put your elbow against the front end of the saddle, and your fingertips should reach about
halfway along the stem. Exactly what you can derive from this, I don't know but it seems to be a
standard test.

Cheers,

--
-Alex ----------------------+ Alex Graham | [email protected] | ----------------------+

 

[Michael Macclan]

Alex Graham wrote:
> Put your elbow against the front end of the saddle, and your fingertips should reach about
> halfway along the stem. Exactly what you can derive from this, I don't know but it seems to be a
> standard test.
>
> Cheers,

'Cyclecraft' says, "With dropped handlebars, if you place your elbow against the front of the
saddle, your fingertips should just be able to touch the middle of the handlebars". But this doesn't
really tell you very much about the top tube length, does it? This distance depends on saddle
position, top tube length and stem length.
--
Michael MacClancy

 

[Andy Welch]

On 19-Feb-2003, "Michael MacClancy" <[email protected]> wrote:

> 'Cyclecraft' says, "With dropped handlebars, if you place your elbow against the front of the
> saddle, your fingertips should just be able to touch the middle of the handlebars".

I've also read (sorry can't remember where) that you put your elbow against the front of your saddle
then put your other hand perpendicular to the end of your figertips on the first hand then the
little finger of your second hand should line up with the middle of the handlebars. In other words
the distance from seat to bars would be around 8cm more with this method than the Cyclecraft one.
Quite a big difference if you are trying to choose a frame/stem.

One option would be to get yourself measured by these guys
http://www.bikefitting.com/English/SitinfFR.html Costs around £35 and you are still just going to
get one version of the ideal bike size, but might be worth a try.

Cheers,

Andy

 

[Jay]

"Geraint Jones" <[email protected]> wrote in message
news:[email protected]...
> Are there any folk rules of thumb about the length of the frame, from say seat tube to headstock,
> like the ones about leg length and seat tube or about clearance when straddling the crossbar?
>
> (I know that the right way of fitting a bike to a person is to try it, but how can someone who has
> never had a bike anything like small enough know that what it feels like is right?)

I spent ages looking for the right sized frame, I am 5'3" and have short legs! The advice I had was
that I needed to be able to lock my leg while sat on the saddle with my heel on the pedal, and I
needed to be able to touch the ground with my tip toes in same position, also not bring my knees up
too high on the top of the pedal rotation as that would make my knees ache more during use.

None of this is formal, just what various bike shops recommended and I have so far found my 26"
framed dawes to be very comfy however other 26" framed bikes were not at all good riding
positions for me.

Good luck

Jay

 

[Andy Welch]

On 19-Feb-2003, "Jay" <[email protected]> wrote:

> I spent ages looking for the right sized frame, I am 5'3" and have short legs! The advice I had
> was that I needed to be able to lock my leg while sat on the saddle with my heel on the pedal, and
> I needed to be able to touch the ground with my tip toes in same position,

As far as I can tell all this tells you is that your saddle is the right height and the bottom
bracket is quite low. Not a bad option for utility riding but you might want a bit more ground to
pedal clearance if you were in the habit of cornering at high speed.

> also not bring my knees up too high on the top of the pedal rotation as that would make my knees
> ache more during use.

This would check that your cranks aren't too long. Not a bad thing to check when you are 5'3" with
short legs, since most bikes come with cranks designed for your average male leg.

However, none of the above tells you whether the top tube and stem are the right length. Not that it
matters if you are happy with the bike but something for the OP to bear in mind.

Cheers,

Andy

 

[Geraint Jones]

[email protected] wrote: ( However, none of the above tells you whether the top tube and stem
are the ) right length. Not that it matters if you are happy with the bike but ( something for the
OP to bear in mind.

The OP is quite happy with the length of his cranks, than you very much. It's the OP's her-indoors
who has short arms.

Oddly enough, she finds that an exceptionaly small man's fleece -- no, a man's XS fleece, there are
no exceptionally short men in this concept -- is the right size and shape for her, whereas I wear a
women's S for the freedom of movement of the arms.

 

[Michael Macclan]

Geraint Jones wrote:
> [email protected] wrote: ( However, none of the above tells you whether the top tube and stem
> are the ) right length. Not that it matters if you are happy with the bike but ( something for the
> OP to bear in mind.
>
> The OP is quite happy with the length of his cranks, than you very much. It's the OP's her-indoors
> who has short arms.
>
> Oddly enough, she finds that an exceptionaly small man's fleece -- no, a man's XS fleece, there
> are no exceptionally short men in this concept -- is the right size and shape for her, whereas I
> wear a women's S for the freedom of movement of the arms.

I guess that rules of thumbs for top tube length are going to be less useful than seat
tube/saddle height?

Top tube length is going to depend on torso length, arm length and riding style whereas seat
tube/saddleheight is only really a function of leg length.

A bike fitting will give you the answers.
--
Michael MacClancy