Racing Pad Taper

The term “pad taper” refers to the degradation of brake material caused by uneven friction between the pad and the rotor face. Regardless of the brand and quality of manufacturing, OEM pads always exhibit some minimal taper right out of the box.

However, this baseline condition is also exacerbated by uneven piston forces produced at the front or rear of a pad once it’s in the caliper and under load. Over time, the process creates significant wear and this causes the pad face to pull away from the backing.

Depending on the type of racing, more or less taper can exist. There are two kinds of pad wear:

Vertical a/k/a radial taper (top to bottom)
Longitudinal taper (end to end)

For example, road courses tend to result in a balanced taper as cars brake, roll, and heat-dissipate more evenly throughout a lap. On the other hand, in oval racing, cars lean consistently to the right so right-side taper is higher. (More about racing pad wear here.)

The resolution of this problem is four-fold:

Use denser pads with deeper material depths
Alter caliper/piston configurations to ensure that even pressure is applied throughout the pad/rotor face cycle
Inspect and rotate pads often
Replace pads frequently

There is no way to avoid pad taper. Rather than being concerned about it, take action early so you understand what your pad taper situation will be before you roll off the hot grid.