ISIS OCTALINK BOTTOM BRACKET TOOL 8 NOTCH PARK TOOL BBT-18

The Park Tool BBT-18 is an 8-notch bottom bracket tool for ISIS Drive and Shimano Octalink cartridge bottom brackets with external notches. It is a heavy-duty investment-cast tool that belongs in every workshop servicing trekking bikes, MTBs and above all e-bikes.

Besides bottom bracket cups, the BBT-18 also removes and tightens front chainring lockrings on several e-bike motors: Bosch Gen 3, Gen 4 and Gen 5 and Specialized Levo with Brose motor. The nominal outside diameter is 43.4 mm and the 36 mm wrench flats let you apply force with a standard open-end or adjustable wrench. The 22.5 mm centre hole will not fit over 30 mm spindles: for those systems Park Tool recommends the BBT-118.

Where to use the BBT-18 bottom bracket tool

• Shimano Octalink drive-side cups with external notches
• ISIS Drive cups, including Truvativ and Bontrager
• Threaded Truvativ ISIS Drive and Giga Pipe
• Bosch Gen 3, Gen 4 and Gen 5 front chainring lockrings
• Specialized Levo (Brose motor) front chainring lockrings

Why choose Park Tool BBT-18

• Heavy-duty investment-cast construction
• One tool for ISIS/Octalink bottom brackets and many e-bike lockrings
• 36 mm flats for a secure grip with a wrench
• Precise 8-notch engagement that reduces the risk of damaging cups and lockrings

Before working on an e-bike lockring it is good practice to remove the battery and the crank arm, clean the notch area carefully and check the motor manufacturer's instructions for loosening direction and tightening torque. The same applies to ISIS and Octalink bottom brackets: clean cup, greased threads and tool fully engaged before applying force.

If your workshop regularly sees Bosch or Specialized e-bikes and bikes with splined-spindle bottom brackets, the Park Tool BBT-18 bottom bracket tool is a tool you will use far more often than you think.