Binky

The frame only LOOKS tiny because the geometry is funny and the tubes are over-sized, which makes the bike look more like a toy than a real bike, but the frame is actually 57cm (22.5 inches).
A local fellow was cleaning out his garage today and had this antique aluminum 1987 ST600 surplus to his needs.
It has a triple chainring set (Biopace 28/44/50)and looks like it would accept touring gear - so I am delighted.

Do these old American-made Cannondale touring bikes keep their value ??

Shimano 600 hubs, headset callipers & levers, Shimano Deore SIS shifters & levers, Mistral rims, Nitto stem, TTT bars.

scozim 

In that condition, I'd say it would probably keep it's value. Nice looking bike.

oddjob2

That is a touring setup on that bike. The paint appears to be in good shape, an easy sale as shown for $250 or more, assuming it needs tires, cables, etc., and a full overhaul.

I'd recheck the frame size though. No way that is a 57cm. That would make this 86(?) ST400 an XL frame, and I normally ride a 58cm.



Below is a LL Bean Cannondale, same frame as yours Binky. Note how much seat post is exposed to accommodate my 5'9" height.

rccardr 

That may actually be a 19 inch frame. First two digits of the serial number (look under the chain stays) will tell you.

Binky

OK, Guys..... Am I doing something wrong ??

You spooked me enough to go and check.
Easy enough to do.
See the attached pictures: I tied a measuring tape to the seat tube.
And the guy had the original bill of sale from early May, 1988, that describes the bike... which says the bike has a 22.5" frame.

And tell me more about the first two digits of the serial number being relevant to the frame size.

oddjob2

Although more than one way to measure, I believe the convention is center to center for measuring. So it should be from middle of top tube to bb.

https://www.coloradocyclist.com/bikefit

Binky

OK ---- Obviously the people at the bike shop used the length of the seat tube instead of centre to centre to establish the frame size and wrote 22.5 inches on the bill, which (as I understand it) is customary for vintage steel-framed bikes.

I found the serial number stamped on the bottom of the chain stay and checked the Cannondale frame numbering methods from the 1980s, as found on the internet.
The first two digits of the 11 digit serial number are 21.... indicating a 21 inch frame.
The next 6 digits (mm/dd/yy) indicate the date of manufacture.
The last three numbers are the sequence number.

Now we know....

Thanks guys. My wife is now thinking of flogging her Trek 1220 and absorbing this Cannondale ST600.