This clearly is when the component was made and not when the bike was made, but unless the component or bike manufacturer had lots of stock lying around in inventory, the date should be a fairly good indication of the year of the bike.At least it would be the earliest date that the bike could have been made.Most of what I've learned has been gleaned from others, including a former regional sales manager for Western States Imports (WSI), the Canoga Park, California company that designed, had manufactured in Japan and marketed in the US and elsewhere its Centurion road bikes and, later, its Diamondback mountain bikes.The story begins in 1969/70 when WSI was formed by Mitchel Weiner and the first Centurion road bikes were introduced into the US market, mostly on the US West Coast.Tange's seamed Infinity Cr Mo tubing began replacing high-tensile tubing on mid-priced Centurion models, such as the popular Le Mans RS, Super Le Mans and Le Mans Mixte models, by the early 1980s.Lower- end models of this period featured Infinity tubing for the three main tubes and high-tensile tubing for seat and chain stays and fork blades.[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.
The road bicycles are the museum's largest category and are divided by manufacturer, with first U. companies (Schwinn, Trek, and Raleigh America), then Italian (Bianchi), French (Peugeot, Motobecane and Roold), Japanese (Nishiki, Fuji, Kuwahara, and Univega), and Taiwanese (Giant). For example, Raliegh was historically an English company.The difference in weight between Champion #1 and #2 tubing (and the later high-end tubing used for Centurions, simply labeled Tange #1 and Tange #2 by about 1985) was so small (less than 3oz for a 58cm c-c frame, all eight tubes) that it seems a bit silly to debate supposed frame quality differences between these two high-end tubesets.The thing to remember is that the high-end Tange tubesets were high-quality Cr Mo steel which were on a par with high-end Columbus SL/SP (Cr Mo) and Reynolds 531 (manganese-molybdenum) tubesets.While Weiner focused on running the business and on marketing, "Cozy" Yamakoshi served as WSI's product development manager, doing most of the frame design work and coordinating and supervising the manufacture of his creations in Japan and exporting them to the US.
The earliest models of the Centurion line had high-tensile steel frames but by the late 1970s and into the early 1980s Centurion's pricier models, such as the Professional and Semi-Professional (late 1970s), Pro-Tour (late 1970s to early 1980s) and the Turbo and Comp TA models (early 1980s) featured Tange's high-end Champion #1 or #2 tubing, a double-butted, seamless chromium-molybdenum (Cr Mo) steel alloy.
They operated the company — widely known as West Coast Cycle (or WCC) — with their daughter Louise and sons Leo Jr. Howie Cohen subsequently took over the business, followed by his brother.