I have a period-correct, if not original, SunTour XC 7000 on my Schwinn, with a 48-40-28 or 48-40-24 ringset. With the latter configuration I have to be a little careful on upshifts out of low, but otherwise both work fine.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069