Aluminum Bottom Bracket Socket BSA30 (Threaded BB30)

BSA30 is the threaded variant of the 30 mm-spindle BB family. Same 1.37" × 24 TPI shell threading as standard BSA (so it threads into a regular BSA frame), but the cups are bored for a 30 mm spindle instead of 24 mm. Race Face Cinch, Rotor 30 mm cranksets, and other 30 mm-spindle cranks that need a threaded-shell installation use BSA30 cups in BSA-threaded frames. There is no ”BSA30 press-fit“ variant; the press-fit equivalents for a 30 mm spindle are PF30 (42 mm shell ID, 68 or 73 mm shell width) or PF30A (Cannondale's offset variant).

The 1671 Aluminum BB Socket cut for BSA30 seats on the cup's 12-notch outer profile (44.2 mm notch diameter) with full contact on every notch. The aluminum body matches the cup's hardness; the engagement is deep enough that the notches don't lift at the installation torque the cup maker specifies.

Why a separate socket exists for BSA30

A 30 mm-spindle threaded cup is dimensionally different from a 24 mm-spindle HT2 cup, even though both thread into BSA-pattern frames. BSA30 cups carry 12 notches on a 44.2 mm notch diameter, where Hollowtech II cups carry 16, so the notch count and the notch diameter both differ. A standard 16-notch HT2 wrench will engage on a BSA30 cup only partially, because 16 teeth cannot seat in 12 notches, and that reduced contact is what rounds the notches under torque. The dedicated BSA30 socket eliminates that risk by sizing to the cup's actual geometry.

Compatibility

• BSA30 cups on Unior's compatibility chart: Race Face Cinch, Rotor BSA30, SRAM DUB, Zipp Vuma, and Hawk Racing BB3086 (threaded cups in BSA-threaded frames)
• Cups bored for a 30 mm spindle with the 12-notch BSA30 interface (44.2 mm notch diameter)
• Not for PF30 / PF30A press-fit shells; those need a press-fit BB removal tool, not a socket
• Not for standard BSA (24 mm spindle); use the 16-notch generic or BBR60 socket

Specs

• Drive: 1/2" square drive (use with a torque wrench, ratchet, or fixed handle such as the Pro Socket Handle)
• Material: CNC-machined aluminum, red-anodized
• Notch fit: 12 notches on a 44.2 mm notch diameter; 53 mm socket diameter, 31 mm wide, 117 g (Unior datasheet)
• Includes: the socket itself; pair with the Bottom Bracket Socket Retaining Tool for low-profile cup engagement

Built in Zreče

Unior has been forging hand tools in Zreče since 1919, and sponsors professional road and mountain-bike race teams. The BSA30 socket is the cleanest example of why the 1671 family is cut to the specific cup pattern, not to a generic envelope: 30 mm-spindle BB cups landed in shops without a dedicated socket for most of the last decade, and shops worked around it with marred cups and rough notches. The BSA30-specific tool retires that workaround.

Pro tip from our mechanics

The most common BSA30 confusion in the shop is the threaded-vs-press-fit question. The BB30 standard (no “BSA” prefix) is press-fit at 42 mm shell ID, no threading involved; BSA30 keeps the BSA threading and just bores the cups for a 30 mm spindle. If the frame's BB shell has BSA threading visible at the entry and the crank runs a 30 mm spindle, the cups are BSA30; if the shell is unthreaded, it's BB30 / PF30 and this socket won't apply; the BB30 Bearing Puller handles the press-fit case.

For the install / remove procedure and torque values: Replace or clean your bottom bracket →.

FAQ

Which bottom bracket cups does the 1671.BSA30 socket fit? Unior's compatibility chart lists the BSA30 socket for Race Face Cinch, Rotor BSA30, SRAM DUB, Zipp Vuma, and Hawk Racing BB3086 threaded cups. The interface is 12 notches on a 44.2 mm notch diameter. Praxis M30 cups are a different 12-notch size, about 46.3 mm across the notches, and are not on this socket's chart.

Will a standard 16-notch Hollowtech II tool work on BSA30 cups? No. BSA30 cups carry 12 notches and Hollowtech II cups carry 16, so a 16-notch tool cannot seat fully and the partial contact rounds the notches under torque. Shimano Hollowtech II cups take Unior's 16-notch 1671 socket; BSA30 cups take this 12-notch socket.

Does this socket work on BB30 or PF30 press-fit bottom brackets? No. BB30 and PF30 shells are unthreaded, so their bearings and cups press in and come out with a bearing puller or a press-fit removal tool rather than a socket. BSA30 is the threaded version: a BSA-threaded shell with cups bored for a 30 mm spindle, which is what this socket drives.

What are the socket's dimensions, and does it need an adapter? Unior's datasheet lists a 53 mm socket diameter, a 44.2 mm notch diameter, 31 mm width, a 1/2-inch square drive, and 117 g. It is a one-piece socket with no guide or adapter and no spare parts. For low-profile cups, the 1671.RET retaining tool keeps any 1/2-inch aluminum socket engaged on the cup.