Can I use Shimano Ultegra 6800 BBR60 Bottom Bracket on 105 groupset
Any hollowtech II bottom bracket should be compatible with your crankset. For the frame, you will need to make sure you get the proper thread. Most frames will be BSA thread. Older Italian frames will be Italian thread. If your frame is Italian thread, both bearing cups will thread on clockwise. If it is not, the drive side will thread on counter clockwise. Pay attention to the spacer arrangement on your frame and install the bottom bracket with the same arrangement. Should just be a pretty simple swap.