BB-RS500-PB GRX Bottom Bracket (Press Fit 86.5mm Shell Width)
The Press Fit BB-RS500-PB bottom bracket is recommended by Shimano for the GRX, Tiagra, Sora and Claris series. This allows a Hollowtech II or 2-piece crank with a 24 mm axle to be mounted in a road frame with an 86.5mm bottom bracket width and a 41 mm shell diameter. The bottom bracket is made from a synthetic material and has black bearing cups.