Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Me89'Jimmy, Jun 10, 2003.
Can someone explain to me what tire ply is and what bias plys is?
Go here it shows you a picture and I believe they are called bias ply because the biases or direction the steel cords in the plies criss cross each other. Hope this doesn't confuse you even more as it almost confused me writing it /forums/images/graemlins/laugh.gif /forums/images/graemlins/rotfl.gif
I believe ply = the number of layers of belts in a tire. Bias ply means the belts go across the tread from one bead to the other. Radial means the belts go around the radius of the tire. There are many opinions of which is better to run for certain applications but I am not knoweledgable enough to talk about it.
not to rag on you gravdigr, but im pretty sure its the other way around. radial plys go from bead to bead. bias play goes around the tire. this is why radial truck tires have indented or bulged sidewalls in 1 or 2 spot which is normal.
You're probably right, I knew it was one way or the other which was why I included the "I believe" and "I am not knoweledgable". I figured if I answered wrong someone would set me straight and it's better than no one answering at all /forums/images/graemlins/wink.gif
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The body is made up of several layers of different fabrics, called plies. The most common ply fabric is polyester cord. The cords in a radial tire run perpendicular to the tread. Some older tires used diagonal bias tires, tires in which the fabric ran at an angle to the tread. The plies are coated with rubber to help them bond with the other components and to seal in the air.
A tire's strength is often described by the number of plies it has. Most car tires have two body plies. By comparison, large commercial jetliners often have tires with 30 or more plies.
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from here http://auto.howstuffworks.com/tire1.htm
Practically speaking, there are some general trends for bias plys and radials. A radial tire will ride better and last for more miles. A bias ply has a harder time being true (round), but flexes great and gives good off-road performance. They are generally considered to be tougher, as well.
Since the radial tire was invented (30 years ago? I don't know), they have taken over the entire passenger car/truck market, so now you only see bias plys in heavy equipment and off-road tires.
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