I have and early GT with euro bottom bracket. The serial # is 181569. Initially I thought this was an 81 but doesn't seem to make sense with the way I have been seeing the other ones dated. The top tube is unstamped behind the seat tube. Any info would be appreciated.

Euro BBs were an option on the regular size frames - sounds early 81 to me.

Pretty sure its Jan 81. I think the Pro TT length is 18inch and the standard 17inch. Euro BB was an option on 82 Pro frames but not sure of 81. Does it have holes drilled in the dropouts?

jan of 81, 569th frame.

What diameter is the down tube? Down tubes on 81's were a smaller diameter than 82-83's/

Pro Top tube lengths are 18.5", and the Experts are 17".

I just took photos (of a GT frame I have had since early 80s). The serial is on the inside of the chain side rear dropout and reads 108830.The fourth 8 could be a 9 due to grinds. It is a euro BB.

Any help on ID?