This article will discuss the use of the BBT-18 (or older BBT-8) to remove some crankset spider lockrings
Some MTB crankarms use a detachable spider or chainring mounting arms. These spiders use internal splines at the center, and are held to the crankarm with a lockring. The Park Tool BBT-18 (or older BBT-is designed to fit this eight notched lockring. The tool also fits the cups of the Shimano® XTR 950 Bottom Bracket.
If the lockring becomes loose, it will cause a creaking sound when the bike is ridden, similar to a loose crankarm bolt. Check the security of this ring using the BBT-8.
Procedure for Servicing Lockring
- Remove the crankarm from the bike. For help removing the crankarms, click here
- Notice there is a snap ring over the lockring. Remove this with a screwdriver.
- Place the BBT-8 in the notches.
- Hold the crankset secure in the soft jaws of a vise. Use a rag to minimize any scratching on the arm.
- Loosen the lockring counter-clockwise. Note the BBT-18 has a 36mm wrench flats. The Park Tool HW-2 wrench in preferred, as it wraps around the tool flats.
- To assemble, grease or oil the threads. Alternatively, you may apply a mild thread locking compound such as Loctite® #242.
- Secure the lockring fully. Shimano® recommends 443-620 inch-pounds on their lockring. If you are attempting to torque by feel, that is 38 to 50 pounds of effort on a wrench held twelve inches from the center of the lockring.
- Reinstall the arm.