Next week, NASCAR will start the 2015 season at Daytona. The next few weeks will be filled with testing, practice and qualifying. Stopping these cars will be not your off-the-shelf pads from your local retail parts store. The pads they will be using are specific for the high-speed ovals.
Brakes will not be used much during green flag racing, but they needed to warm up fast to avoid “the big one” and haul the cars down from racing speeds to pit lane speeds.
To do this requires a special type of caliper and pad. Most of the cars will be using a four piston caliper in the front and a two piston caliper in the rear. These calipers are extremely light weight to reduce unsprung mass and ultimately improve handling.
The pads are also light weight. They are typically thinner than a pad they might run at a shorter track. But, they also have to be able to go from a low temperature to an extremely temperature in a second. These types of mechanical and thermal shock would shear the friction material off most brake pads.
To keep the material on the pad a large percentage of the cars will have backing plates with the NUCAP Retention System or NRS. This mechanical retention system uses small hooks on the backing plate that bite into the friction material. Also, there are no holes in the plate so the pedal will be stiffer.
During qualifying, some teams would minimize brake drag by pushing the pads as far back into the caliper as possible. Some have even used zip tie to secure the pad in the caliper. This is why you will hear some crew chiefs over the radio tell the drive to pump the brakes after their run is finished.