A gear case, also known as a chain case, is an enclosure for the bicycle chain an sprocket assemblages commonly employed by utility bicycles. It serves to protect the chain from mud and dirt and tends to fully enclose the drive train. It is similar to a variety of structures called chainguards which provide only partial coverage and prevent the lesser inconvenience of a rider having their clothes soiled by the bicycle chain as well as the greater menace of getting them caught in the chain or the crank rings.