he 105 BB-5500 bottom bracket from Shimano is an Octalink bottom bracket with 8-speed gearing and a steel axle. The 109.5 mm versions are compatible with 2-way cranks, the 118.5 mm versions with 3-way cranks. Even though it has been around for a while, this bottom bracket still holds up. Specifications: Application: Road Series: 105 5500 Type: BSA, ITA Shell Width: 68 mm, 70 mm Axle Length: 109.5 mm, 118.5 mm Axle Type: Octalink (Road) E-Type Compatibility: no Chaincase Compatibility: no Technical Information: Bearings: steel Axle Material: steel Bottom Bracket Cup Material: Aluminium Compatibility: – Octalink crank arms with eight-speed splines for shorter grooves (Octalink MTB) Features: – 8x toothing of bottom bracket axle and crank Technology: Octalink In Shimano’s Octalink system, the bottom bracket and crank are connected by an 8-tooth contact surface. This provides greater rigidity and greater load capacity, especially compared to conventional square systems. Models: BSA 68×109.5: Threads: BSA Shell Width: 68 mm Axle Length: 109.5 mm Compatibility: 2-speed Manufacturer Number: E-BB5500B09 BSA 68×118.5: Threads: BSA Shell Width: 68 mm Axle Length: 118.5 mm Compatibility: 3x Manufacturer Number: E-BB5500B18 ITA 70×118.5: Threads: ITA Shell Width: 70 mm Axle Length: 118.5 mm Compatibility: 3x Manufacturer Number: E-BB5500I18
