Shimano Press Fit Road Type Bottom Bracket BB71 SM-BB71 Shimano Ultegra-quality press-fit bottom bracket Complete Ultegra level press-fit bottom bracket assembly for Shimano HollowTech II road cranks. The set includes left and right hand cups, inner cover and inner O-rings. The fibre-reinforced polymer cups are lightweight and reduce the chance of frame noise. Maintenance free sealed cups keep out dirt and water. Compatible with 86.5mm bottom bracket shells. 41 mm cup diameter. Easy press-fit installation