Yes, it's all in the brake caliper slots. If the distance from the bottom of the front axle to the bottom of the front brake slot exceeds 315mm, you won't be able to use a standard 27x1-1/4" wheel without either replacing or lowering the brake caliper. If it exceeds 311mm, that rules out a standard 700C rim. If it exceeds 295mm, you cannot use a standard EA-3 26x1-3/8" rim.
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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