Premium Bottom Bracket for Brompton Bikes The White Industries External BSA Bottom Bracket brings precision engineering and long-lasting performance to Brompton folding bikes. Made in-house at White Industries' California facility, this bottom bracket features Enduro stainless steel angular contact bearings housed in precision-machined BSA threaded cups. The 30mm spindle diameter provides the ideal fit for Brompton cranks while the external bearing design places bearings outboard of the frame's bottom bracket shell for improved stiffness and bearing longevity. Built to BSA (Birmingham Small Arms Company) thread standards—also known as British or English threading—this bottom bracket uses the 1.37" x 24 TPI thread specification that's standard on Brompton bikes. White Industries' machining precision ensures smooth threading and proper bearing preload, while external seals protect the stainless steel bearings from water, dirt, and contamination. Available in seven anodized colors with machine-engraved logos, these bottom brackets combine performance with distinctive style. Built to Last Made in the USA at White Industries' California facility with precision CNC machining. 30mm bearing size specifically compatible with Brompton cranks and other 30mm spindle cranks. Enduro stainless steel angular contact bearings provide smooth rotation and long service life. External bearing design positions bearings outboard of the bottom bracket shell for increased stiffness and improved bearing protection. BSA threaded cups use standard 1.37" x 24 TPI British/English threading for universal compatibility. Designed for 68mm or 73mm wide bottom bracket shells. External seals sit directly against bearings to keep out water, dirt, and contaminants—part numbers molded into seals face outward. Anodized finish with machine-engraved White Industries logos for durability and style. Available in seven colors: Black, Blue, Gold, Pink, Purple, Red, and Polished Silver. Serviceable design allows bearing replacement to extend bottom bracket life.
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