Originally Posted by
Squeazel
Very nice looking bike!
If it's a Miyata-built Gran Turismo, then the "I" says the frame was built in 1980. Mine has an "M" at the beginning of the serial number, and it was built in 1984. It's probably quite similar to the Miyata 610 of the same year- mine is identical to the 1984 Miyata 610. Somebody has posted Miyata catalogs that may give you more information about your bike- search on "Miyata Catalog".
Looks like my bikes twin. Mine is serial # H381940 and I estimate it as a 79/80 based on the component dates and the following article in Bicycling magazine. I think you'll enjoy it. It's my favorite bike and it gets plenty of usage.
http://www.wooljersey.com/gallery/v/...g-1980-03-A-3/
