Frame sizing - Rules ???

[neilll]

I've never properly got my head round this one, maybe someone can give me the basics...??

I've noticed that many here are very fussy in respect of frame sizes but it's not something I pay a huge amount of attention to.

My Pace is 18", as is my Rocky, my Funk is 17.5" and my 'Dale is 16.5". The 'Dale is showing quite a lot of seatpost but does that mean it doesn't 'fit' me?
I don't find it uncomfortable to ride....

The Rocky has a mahoosive long top tube but doesn't feel too stretched but looks silly next to my other frames.

I'm 5' 10" and have a 32" inside leg if that helps...???? :? :?

 

[cherrybomb]

I find top tube length is more important.

I can live with about a 22" top tube +/- 1/2"

Edit: Oh!, and I'm about the same height as you.

 

[orange71]

I have to pay a lot of attention to frame size as I have 35" inside leg, but a relatively short back, so I need a 21" min. seat tube ideally, but a relatively short top tube (22" is fine for me else I am stretching). Combine that with a long head tube so I don't have to reach down to far (otherwise arse up nose down) and you've got an odd shaped frame :roll:

 

[neilll]

I find top tube length is more important.

Is that so your are not hunched/bunched up/overstretched....right?

 

[stevet1]

There is an exact ratio of amount seatpost showing to frame size that needs to be maintained.
Otherwise it looks cack.
That is all.

 

[cherrybomb]

Yup.

Anything under about 21.5" feels cramped and Over 22.5" seems too stretched out.

I'm not keen on having too short or too long a stem, but i will go with a seatpost with a little layback in it to compensate.

 

[cce]

i can easily cock a leg over an 18 or 19in kona, but stem for stem (and i like the way a 120mm steers on a kona) the 19in feels too long

 

[neilll]

Makes sense...most of my stems are 130mm/140mm

I found this, dunno if it stacks up with you guys (I don't have most of those measurements available but will try it later)

http://www.competitivecyclist.com/za/CC ... M&units=in

 

[andrewl]

Effective top tube is the most important measurement for me. anything less than a 23" effective is too short (excluding DH frames) and I prefer something around the 24" combined with a 110mm or 120mm stem for XC. Seattube angle also influences things a little too and I'll use a setback post for steeper seat tubes and a straight post for slacker ones to ensure my legs are in the optimum position for me.

Head tube length can also be important and most of my modern rides have about a 5" headtube along with the 24" eff top tube.

It always makes me cringe when I see a bike with an absurbly long stem and the seat pushed back on the rails as the rider tries to compensate for a bike which is too small for them as was the norm in the early 90s.

If you look at any pros bikes they look correctly proportioned withe the stem length and amount of exposed seat post looking visually right. As one of my old coaches said " if it looks wrong, it probably is".

 

[orange71]

that's true for most people - but us freaks with odds dimensions don't have much choice unless we go custom. I'm thinking my only option might be 29er to get everything in proportion.