Tires: tire chop, Heel and Toe Tire Wear, Choppy Tire Wear

Question
what causes the chop effect on the tread of a tire ?
if you run your hand over the face of the tread if fells like a series of small ramps

Answer
Jim,

There are 3 causes:

1)  It's normal wear due to the fact that a tread element has to bend as it goes into the footprint, then holds on , then suddenly releases as that same tread element exits the footprint.  This is called "heel and toe wear", because the leading edge gets a rounded appearance and the trailing edge gets a pointed edge.  It resembles a foot.

2)  In excess, "heel and toe" wear is sometimes caused by constant high torque - like when traveling up a hill.

3)  Misalignment, especially toe, can exaggerate the effect.