You need to know your cycling inseam, not your trouser inside-leg. This number gets multiplied by 2/3, to get your frame size. My inseam is 81.8 centimeters (32.2 inches). Multiplying, the frame size is 54.5 centimeters (21.5 inches). This length is compared to the seat tube length center to center. That's the basic frame sizing approach. This approach generates a size that is at the large end for me, but that's probably more correct for a vintage bike.
The other attributes of bike and frame fitting are still significant, but they are still secondary to saddle height.
Ken Freeman Ann Arbor, MI USA
On Fri, Mar 20, 2009 at 3:06 PM, James Doolittle <
JDoolittle@bentwaterclub.com> wrote:
> I am a rider, not a collector or mechanic. I was fit in my mid twenties
> by a man who was in his 70's at the time, Ceasar Moretti Jr. He was a
> six day racer in the 1930's thru the 1950's. This was over 30 years
> ago. He got it right. I'm 57 years young now and that frame size is
> still what fits the best. Over the years I've always had at the minimum
> two bikes and as many as seven at one time. Almost all within the CR
> timeline. Like many on the list, I've crashed, had stolen, been given
> by teams, bought as junk or from the most reputable shop many, many
> bikes over the years. I've experimented with sizes as much as 3
> centimeters one way or the other and always sold those bikes. A couple
> were very impressive bikes that anyone in their right mind might have
> kept, but they never felt right. The key is to stick with your best
> fit. Happy riding!
>
> James Doolittle
> Spring, Texas - where the dogwoods and redbuds are blooming in the
> forest!, Texas
>
>
> -----Original Message-----
> From: classicrendezvous-bounces@bikelist.org
> [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of Robert
> Goughary
> Sent: Friday, March 20, 2009 12:34 PM
> To: classicrendezvous@bikelist.org
> Subject: [CR] vintage frame size question
>
>
>
> This is a good one for all you with more experience than me -
> particularly those of you that have built frames or sized people up in
> shops, etc...
>
> when buying a vintage frame sight-unseen, how do you know if the frame
> will fit? Not - what would be the perfect fit - but let's say you run
> across a Richard Sachs from the seventies and the only thing you know is
> seatpost height - what do you do?
>
> I am 5'11" or so - normal build and size - how do i know what are the
> fitting extremes? - what is to small, way too small and too big and way
> too big? Example - can a 6' guy fit on a 54" frame? Or a 60cm? (seatpost
> C-C)
>
> I have a couple bikes that fit - so i'm more concerned about the random
> find online or maybe at a flea market, etc...
>
>
> Thanks
>
> Rob Goughary
> Stamford, CT USA