YST BB-993 Bottom Bracket

The smart fix for stripped threads. The YST BB-993 is a patented threadless cartridge bottom bracket designed as a reliable repair solution for frames with damaged or stripped bottom bracket shell threads — saving you from a costly frame repair or replacement when standard threaded bottom brackets can no longer be installed.

Rather than threading into the frame shell in the traditional way, the BB-993 uses a threadless compression-fit design that seats securely in the shell using its bevelled steel cups, then threads into itself to clamp the unit in place. The result is a secure, stable fit that restores full bottom bracket functionality to a frame with compromised threads, without any welding, helicoil inserts, or specialist tools.

Double sealed cartridge bearings provide smooth, durable rotation with excellent moisture resistance, and the JIS square taper interface ensures compatibility with a wide range of square taper cranksets for both MTB and road applications. Fits 68mm BSA English-threaded shell frames with a 33.5–38mm shell ID.

Available in two axle lengths: 116mm and 122.5mm.

Key Features:
- Threadless cartridge design — repair solution for stripped or damaged BB threads
- Patented bevelled cup system — threads into itself, no frame thread engagement required
- Double sealed cartridge bearings — smooth, water-resistant rotation
- JIS square taper axle interface
- Compatible with MTB and road square taper cranksets
- Fits 68mm BSA English-threaded shell frames
- Shell ID: 33.5–38mm
- Available axle lengths: 116mm and 122.5mm
- Installation torque: 40–50Nm
- Includes crankset fixing bolts