Even those equipped with Suntour Superbe components usually had SR seatposts.Many components are marked with size descriptors in addition to component manufacturer's date codes.)Most early Treks (1976 through about 1980) were sold as framesets.The components were added by the local bike shop or by the buyer. Components also could be swapped from an existing ride to the new frameset.The Appendix gives dates of initial manufacture for the vast majority of derailleurs made from 1920 to 1999.Other manufacturers of bicycle components have date marks on their pieces.Swaps also can be made as the bike falls out of favor, or is being sold, where the higher quality components are traded for lower quality ones that the owner had onhand.
However, a Gran Compe set of calipers had no markings. For example, 1182 means the 11th week of the year 1982.[Atom] [Brooks] [Campagnolo] [Dia-Compe and Weinmann] [Huret] [Maillard] [Normandy] [Nitto] [SR (Sakae)] [Sachs-Huret] [Shimano] [Strong] [Sansin] [Sunshine] [Sun Tour (Maeda)] [Sugino] [Tange] [Williams] [Dancing Chain] [Saddles]The date of manufacture of a bicycle's components can often be used to determine the date of manufacture of the bike itself.Some bike parts have a date code cast or stamped into the piece.As the wear on a vintage bike increases, the greater the likelihood components are not original, either through replacement of worn parts or through component swaps.Swaps can take place early in the life of a bike as the proud new owner upgrades to new or used components of higher quality.Dia-Compe cantilever brakes don't appear to have a date code, but supposedly the 981, 983, 986 brakes were first introduced in 1981, 1983, 1986, etc.Following Ben's lead - I checked three sets of Dia-Compe G calipers and all have the four-digit date code on the back of one of the arms.For old Treks, 27.2 is the most common, but for other bikes the diameters can range from 25mm to 33mm.The rear derailleur can often be dated to a year or two by referring to the book "The Dancing Chain - History and Development of the Derailleur Bicycle", by Frank Berto, 3rd edition 2009.This makes dating the components an interesting archeological investigation, but one not necessarily related to the date of the bike. Trek owner Larry Osborn made this observation, and suggested this as a supplementary way of dating a Trek (and other bikes as well).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).