Square Taper Bottom Brackets

Square taper bottom brackets are a sealed cartridge unit with a tapered square spindle. The cartridge threads into a Euro (BSA) shell, and adapter cups let it fit some other shells. They’re simple, reliable and cheap, which is why you’ll find them on entry-level, junior and retro bikes. They come in a range of spindle lengths to suit your cranks and chainline.

They only fit square taper cranks, so check your crank type, spindle length and frame shell before ordering.