There should be a BB length printed on the bearing body. The first # should be 2 digits, and that tells the diameter of the BB threads. The second # is the length of the spindle. Common #'s are 109.5 (road doubles), 114.5 (?) (triples), etc. If the bike was a department-store bike, however, who knows what the original length was? Non-standard parts on these bike cause all kinds of problems.
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