Bias-ply tires are a type of tire construction where layers of fabric, known as plies, are arranged diagonally. This design allows the tire to flex more easily, providing a comfortable ride and good traction on various surfaces. Bias-ply tires are commonly used in vintage vehicles and some off-road applications due to their durability and ability to handle rough terrain. These tires typically have a stiffer sidewall compared to radial tires, which can lead to better stability when cornering. However, they may not perform as well at high speeds or in wet conditions. Overall, bias-ply tires are suitable for specific uses, such as classic cars and certain types of off-road vehicles.