Join Date: Apr 2009
Location: Oklahoma, U.S.A.
Bikes: Brompton H6L-X, Dahon Curve D3
Check the serial number to determine the year --- if a U.S. model, the first letter is always D, denoting Dahon. The second number is the year of manufacture. The next two numbers are the month of manufacture.
For example, a serial number D302....... would mean a bike produced in 2003, month of February (02). Then a letter T followed by 4 numbers which is the actual number pertaining to the bicycle frame produced that month.
(copied from a posting in the Dahon forum)