Shimano XTR External Bottom Bracket BB90
Compatible with XTR, Deore XT, SLX and other Shimano mountain bike cranks, the Shimano XTR Hollowtech II Bottom Bracket is designed as a replacement for any Shimano 2-piece crankset or any other brand that uses the Hollowtech II standard such as FSA and Raceface. With high quality sealed cartridge bearings, dirt and moisture will have a hard time trying to penetrate the 3 levels of sealing. Since the introduction of the Outboard Bottom Bracket system, Shimano has revised it's bottom brackets to include better sealing and reduced bearing movement when under load. This has led to increased bearing life when compared to competitors offerings. The simple preloading system that is featured on the Shimano crank system allows for almost foolproof setup for tensioning the BB, without over-tightening the bearings and causing early BB death.

The Shimano XTR Hollowtech II Bottom Bracket Features:

• Hollowtech II Design
• Outboard bearings sit on the outside of the frame in order to utilise a larger diameter bearing and a wider platform
• Cup Material: Forged and machined alloy
• Bearings: 2 Japanese Sealed Cartridge Bearings 
• Dust seals included
• Weight: 88 grams
• Bottom Bracket Shell Width: 68 or 73mm