bottom bracket size
12-04-04, 12:06 PM
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bottom bracket size
Does your BB size conform to the size to the shell, or what? When I look at cranks they tell me what size BB to purchase with the crank...so where does the shell come into play?
Thanks, I read the section on BB and cranks in Zinn's maintaince manual at midnight last night and I have to much homework to read it again.
Thanks, I read the section on BB and cranks in Zinn's maintaince manual at midnight last night and I have to much homework to read it again.
12-04-04, 01:39 PM
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Bikes: 1959 Capo Modell Campagnolo; 1960 Capo Sieger (2); 1962 Carlton Franco Suisse; 1970 Peugeot UO-8; 1982 Bianchi Campione d'Italia; 1988 Schwinn Project KOM-10;
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You need a few critical dimensions:
1) Cup thread and diameter, generally 24 TPI and 1.37" English/ISO on newer bikes, although I THINK some (Italian) frames are still being made with 24 TPI x 36mm Italian threading, for some inexplicable reason.
2) Bottom bracket shell width, generally 68mm (English/ISO road, also obsolete French or Swiss), 70mm (Italian road, generally with Italian threading), or 73mm (English/ISO for fat-tubed frames).
3) Overall spindle length, a function of number of chainrings and brand of cranks, typically something like 102 to 123mm.
4) On old-school non-cartridge BBs, the thickness of the cups ("thick" or "thin") and the spacing between the bearing races on the spindle.
1) Cup thread and diameter, generally 24 TPI and 1.37" English/ISO on newer bikes, although I THINK some (Italian) frames are still being made with 24 TPI x 36mm Italian threading, for some inexplicable reason.
2) Bottom bracket shell width, generally 68mm (English/ISO road, also obsolete French or Swiss), 70mm (Italian road, generally with Italian threading), or 73mm (English/ISO for fat-tubed frames).
3) Overall spindle length, a function of number of chainrings and brand of cranks, typically something like 102 to 123mm.
4) On old-school non-cartridge BBs, the thickness of the cups ("thick" or "thin") and the spacing between the bearing races on the spindle.
__________________
"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
"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
