Many components are marked with size descriptors in addition to component manufacturer's date codes.
For example, the back of cranks are usually marked with crank arm length in mm, typically in the range of 165 to 185.
Pull the lever and look inside the top of the lever arm for a code such as "1084." Dia-Compe extension levers (yuck) also tend to have date codes on the side that faces the brake hood.If you know of other components that are marked or coded that can be added to this list, please let me know.: The information on this page is copyrighted.Feel free to quote small parts of the information on this page, but copyright law requires be listed as the source of the information.Fueled by this first realization, and with the help of other bike folks, Larry and I have sorted out other codes (a project still ongoing).Especially useful, and challenging to sort out and verify, was the Shimano code.Virtually all of the Treks not equipped with Campagnolo or Shimano Dura-Ace components, started life with some grade of SR seatpost and may also have SR stems, bars or cranks.