700c tires are a type of tire found on bicycles. The 700c size is the most common tire size used on bike makes and models. This tire size is also the largest of the common tire sizes, with a rim diameter of 622 mm.
Size 700c tires are generally used as road wheels due to their good aerodynamics, low weight and strong overall performance. These same features make them excellent selections for road racing bikes and mountain bikes. The number 700 refers to the diameter of the tire, and although the c historically represented the width of the tire, today it has less significance and has more use as a marketing tactic.