I'm looking for a Vintage Cannondale like my 1995 F700, But I don't remember my frame size. 1995 Cannondale Catalog just says, Small, Medium & Large. What did Cannondale use to measure frames and what measurements make a Small, Medium, Large??

https://vintagecannondale.com/year/1995/1995.pdf

In the above link, the F700 for 1995 came in small, medium, large & xlarge sizes (p.51 PDF, p.52 paper catalog).

Then on the next page (p. 52 PDF, p. 53 paper catalog) in the second table for 2.8 series front suspension MTN frames, seat tube sizes are 16.3 in., 19.5 in., 19.5 in., and 21.6 in. for small, medium, large and xlarge respectively.

I was wondering why the seat tube measurements for medium & large are identical, so I looked at other specs. Top tube and wheelbase are greater for the large size vs the medium. So the large has the same seat tube, but the frame is slightly more stretched out.

Hope this helps!

Thanks for pointing out the following page. the pdf is faint and blurry so I missed it! Dang it though, both the Medium and Large have the same seat tube length: More measuring!

Interesting. I measured my seat tube length from the center of pedal's bottom bracket bolt to the top of seat tube was 19". So Cannondale must have measured from bottom of bottom bracket (wish they had drawn out a schematic diagram of their technique). My next question, how to measure the top tube length. From center of steerer to center of seat post tube? Or from top tube weld to weld??

I think I found Wheel Base measurement was the clearest: it has to be from center of axle to center of axle. Which means I have found I have a large frame! Hurrah!
Now to look for a lightly used F1000 or F2000.