Bias-ply tires are an older automotive tire design with crisscrossing fabric cords (nylon/polyester) creating a flexible, but less stable, structure, dominant until the 1970s when replaced by superior radial tires for better handling, heat dissipation, and fuel efficiency; they are now mostly discontinued for general use but still found on some vintage cars, trailers, or specialized off-road vehicles for their specific characteristics.

Construction & Characteristics

Crisscross Pattern: Layers (plies) of cord run diagonally at angles (30-45 degrees) from bead to bead, crossing over each other.

Flexibility: The interwoven structure makes them very flexible, causing the contact patch (tire-to-road area) to change shape under load, leading to inconsistent grip.

Ride Quality: Flexible but can feel "squishy," develop flat spots after sitting, and be difficult to balance, causing vibrations on paved roads.

Heat & Wear: Higher internal friction generates more heat, leading to faster wear and shorter lifespan compared to radials.

Discontinuation & Modern Use

Replaced by Radials: Radials, with cords running straight across (radial) and steel belts under the tread, offer better tread stability, longer life, better handling, and improved fuel economy.