Originally Posted by
Dougbloch
The seller told me that these Sugino cranks are mounted on a Swiss bottom bracket. If I want to put Sugino 75s on it do I need to swap out the bottom bracket for another one? Either a 68mm Sugino 75 BB or an ISO one?
I have a line on the cranks and a Campagnolo Chorus bracket. Maybe I am overthinking this and should just replace the chainring and keep the stock look on it.
NO/MAYBE and YES/MAYBE....
There's a number of Bottom Bracket thread standards:
ISO Right Hand Thread Adjustable Cup Left Hand Thread Fixed Cup (Current World Standard)
1.375" x 24 TPI (Threads Per Inch)
(34.9 x 1.06 mm)
British Right Hand Thread Adjustable Cup Left Hand Thread Fixed Cup
1.370” x 24 TPI
(34.8 x 1.06 mm)
ITALIAN Right Hand Thread Adjustable Cup Right Hand Thread Fixed Cup
36 mm X 24 TPI
(1.417" x 1.06 mm)
FRENCH Right Hand Thread Adjustable Cup Right Hand Thread Fixed Cup (French, Spanish and others)
35 mm X 1mm
(1.378” x 25.4 TPI)
SWISS Right Hand Thread Adjustable Cup Left Hand Thread Fixed Cup
35 mm X 1mm
(1.378” x 25.4 TPI)
RALEIGH Right Hand Thread Adjustable Cup Left Hand Thread Fixed Cup (Obsolete)
1 3/8” x 26 TPI (1.375" x 26 TPI)
(34.9 x .977mm)
ISO and British BBs are interchangeable. They have become the world standard.
French and Swiss have the same size threads but Swiss BBs have Left Hand threaded Fixed Cups on the Right Side (Drive Side).
Bikes with Metric or Swiss Metric threaded BBs haven't been produced since the mid 1980's - ~35 years.
Your choices are going to be limited so you may have to make some compromises.
Here's a link to Sheldon Brown's web page on BBs:
Sheldon Brown's Bottom Bracket Size Database
I put together this Flickr Album on setting up a SS/Fixed French Thread BB. Read the explanations under the pictures:
https://www.flickr.com/photos/282672...7627678462359/
verktyg
Chas.
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Chas. ;-)