Going back to the late 80's I was accustomed to frames obviously being sized based on the seat tube and the measurements were either:
- Center to Center: center of BB to center of seat & top tube juncture
or
- Center to Top: center of BB to top of top tube

Reason for asking; I'm looking to replace my ~ 92 Cannondale 2.8 frame
Current size is a 56 and measures 56cm from center of BB to top of top tube and then 59cm to the top seat tube / collar.
The top tube is also ~ 56cm from center to center (seat / top - seat / head)

I'm looking at an FSC on Ebay; basic search seams that most are reasonably pleased with them.
Looking at what they are calling a size 57 which says the seat tube is 57 bb-top but a top tube of 544.9mm or (54.5cm).
The FSC frame seems to have a slightly sloping top tube but the top tube still seams relatively short.

Anyone familiar with the geometry of this FSC frame?
https://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT

Don't want to be too cramped. I know I can adjust some with a longer stem but afraid of going to long and making the squirly (sp?).

I'm 5'-11" w/ a 32" inseam.

Thoughts on sizing?
This frame?

Seems frame sizing is not as consistent now based upon reading posts and e-bay adds.
Obviously some ebay folks are unaware.

Thanks,
Steve

It would help if you posted an actual saddle height rather than an inseam. Some people post pants inseam, which is irrelevant and other post an actual cycling inseam. A 32 inch cycling inseam would be on the short side for your height. One thing that you can compare, is the head tube length, with the headset. On the 57cm frame is would be in the 163-170mm range, depending on the headset top section height that is chosen for the Campy hiddenset.

You can't deteremine a frame's reach without the TT length and the seat tube angle. Even though the TT length of the FSC frame seems a bit short, the seat tube angle is steeper than average and that increases the reach by .5-1cm, compared to frames with 73.5 or 73 degree STAs.

Most likely you'd need a 10mm longer stem than you have now. That shouldn't be a problem unless you're already using a 130mm.

The only other downside that I see is the frame doesn't come with a fork. You never know exactly what fork length the frame was built for. Road forks vary from about 367mm to 374mm and that is enough to alter the head tube angle by nearly .5 degree and change the steering trail. It becomes a bit of a crap shoot trying to figure out what fork length and offset to buy.

You size frames now by the top tube, so you would want their 59cm frame which has the same 56cm top tube. Know your best TT length range, usually within 1cm, and choose based on that. That has a very steep seat tube so likely you will need a post with good setback to obtain the same distance behind the BB.

oh, actually the above post covers all this so I won't continue.

You don't size a frame just by the TT. The framr reach and the head tube length are very important.