Park Tool

BBT-179 Steel Bottom Bracket Tool

Park Tool BBT-179 Steel Bottom Bracket Tool is a heavy-duty, shop-grade solution for removing and installing select 12-notch threaded bottom brackets and lockrings. Built from precision-machined 4140 steel, it’s designed for repeatable engagement and long service life—especially helpful when dealing with tight, dirty, or threadlocked cups.

• Precision 12-notch fit - Fits 12-notch tool fittings with a 45–47mm major diameter (outside of notches) and 44mm minor diameter (inside of notches) for secure engagement and reduced slip risk
• 4140 steel construction - Resists rounding and wear under high torque, making it a reliable bottom bracket tool for frequent service
• Extra-deep body - Accommodates extra-wide spindles for better tool access on wider crank/BB interfaces
• Low-profile engagement walls - Improves access to recessed lockrings where bulkier tools can interfere or fail to seat fully
• Three drive options - Use a 3/8" drive ratchet, 1" hex, or 36mm wrench flats to match available shop tools and preferred leverage