I would bet it is an 18". The 20" hybrids (at least from that era) had a horizontal top tube and the 18" had a slight angle. For me, I can instantly tell the size of a mountain bike but the hybrids are harder to determine the size by looking at them.
We have three 1989 ST400s (19”, 21”, and 23”) at our house, great riding bikes. All of the 89s that I have seen have indented chainstays that add clearance for larger tires which is nice, especially for larger riders. The indentions started to appear sometime (~November 87 IIRC) during the 88...
Take a picture of the serial number, it will tell you the size. My guess would be 18". I had an H300, 1996 I think, and someone asked to buy it and I made the mistake of letting it go.
I am going to guess it is an 83 or 84. Smaller diameter downtube, no bottle mounts on seat tube and early looking welds make it a very early production ST.
Here are some bad photos of the bike. I have the flu and couldn’t be bothered to pull it out of its spot and take decent pictures. It has a Marzocchi rear shock instead of the Fox unit shown in the catalog.
I am late to the party but I also have an odd Super V with the FH build date. It is a Super V 900 but the colors and components don't match the 1994 mid-year or the 1995 catalog. It appears to be Slick Rock Red/Diamond Black and not the Viper Red/Silver or Viper Red team replica shown in the...
My 1990 ST600 has a unicrown but my 1990 ST400 has the traditional lugged fork. I think they probably used the lugged forks until they ran out of them and that was that.
This one has a BB serial number but the specs match the 85 model perfectly. I am assuming that it is a late 84 built to 85 specs, does anyone know if the AA, BB, CC serial numbers matched the year built or the model year?
Those old Suntour friction derailleurs are so smooth.