Originally Posted by T-Mar

The serial number format is consistent with Bridgestone, though it could be Bridgestone contract manufacture, as opposed to Bridgestone brand. The serial number format could also be interpreted as Miyata. Assuming it is Bridgestone, the serial number, in conjunction with the short dropouts and top tube cable tunnels, should make this mid-1984 manufacture. The lack of down tube shifter bosses suggests entry level and further evidence of this status is offered by the flat cut seat lug, steel headset and lack of finishing at the stay to dropout transition. However, I am surprised to see a forged dropout without a hanger, given the apparent era. Still, I see that it's single speed, so we shouldn't rule out the possibility that the hanger was removed and the frame repainted as part of a conversion. Given the apparent era and level, I'd assume it was designed for 27" wheels? What brand are the dropouts? What size seat post does it use? It may not help but I'd appreciate an overall picture.