HEADSET:
Stronglight D8 - threaded headset - 25 mm x 1 mm (25.4 TPI) French thread - aluminum alloy construction - Clear anodized finish - 3/16" or 4.7625 mm ball bearings without retainers (...44 count total at 22 each upper and lower) - aluminum alloy upper and lower bearing cups with high tensile strength pressed steel inserts - chromium steel head race - 26.4 mm chromium steel crown race - aluminum alloy top lock nut and "keyed" washer - model D8 extra légère ... [For model year 1978, Peugeot PY-10 CP custom ordered bicycles came equipped by default with a Stronglight S5 Super Competition headset. However, one could also optionally specify factory fitment of the Stronglight D6 extra-légere headset. The S5 Super Competition model had been introduced to market back in late 1972 and was Stronglight’s very first reversed cup and cone design (...its P3 and V4 Competition predecessors both used "V" profile upper and lower bearing cups) intended as a direct competitor to the Campagnolo Record headset. It was initially made available having a satin chrome finish, but that was quickly dropped in favor of a more traditional polished chrome look. And while the S5 Super Competition would ultimately prove itself to be a highly durable component, it also had the distinction of being one of the heaviest headsets on the market at that time, weighing in at a stout 225 grams. Debuting at various end of year trade shows in 1976 for general distribution during model year 1977, the Stronglight D6 extra-légere headset was quite literally a part for part design equivalent of the nickel chromium plated steel S5 Super Competition, but one which was manufactured of lightweight aluminum alloy excepting the upper head race and lower crown race which were crafted from high tensile strength chromium steel. The net result was a racing oriented unit that tipped the scales at a much more respectable 125 grams (...and that measurement takes into account a full complement of precision steel ball bearings). Both the chromium steel S5 Super Competition and D6 extra-légere aluminum alloy headsets would continue on in production as Stronglight’s premier offerings until being superseded in 1981 by the S7 Super Competition and D8 extra-légere models respectively. The D8 extra-légere seen here is identical in its external appearance to the D6 but features a revised internal bearing geometry and physically larger ball bearings, both of which have the effect of increasing its net weight to 137 grams (...and that number again includes the steel ball bearings) but which also tend to extend service life when compared to its forerunner the D6 extra-légere.]
