Chain drive system

A chain drive system, comprising:

• a drive sprocket;
• a driven sprocket;
• a chain looped over the drive sprocket and the driven sprocket;
• the chain and the sprocket having respective sliding surfaces slidable relative to each other;
• any adjacent chain components of the chain having respective sliding surfaces slidable relative to each other;
• at least one of said sliding surfaces between the chain and the sprocket and at least one of said sliding surfaces between any adjacent chain components having hard carbon coatings formed on base portions thereof;
• each of the hard carbon coatings having a hydrogen content of 10 atomic % or less;
• and
• a lubricating oil being supplied to lubricate said sliding surfaces between the chain and the sprocket and said sliding surfaces between any adjacent chain components.