Shimano Hollowtech bottom brackets are quite common on modern road bikes, although other systems are regularly seen too. Shimano Hollowtech Bottom Brackets are fairly simple to remove and fit, although a special tool is required to remove the cranks. When replacing the cranks, make sure they are securely fastened, as a damaged pair can be expensive to replace.
This is a long guide, so you can choose to either watch the entire video above, or follow it in smaller chunks by clicking on the individual steps below.
Steps to Replace A Shimano Hollowtech Bottom Bracket:
Modern bikes usually have cranks made of aluminium, they are mounted on an axle made of harder material, usually steel. If there's any play between the cranks and the crank axle the soft aluminium will soon get worn to the point where it's impossible to lock the cranks. If the cranks are loose don't ride the bike.