Knock-back or Knock-off is when the brake pad has been forced away from the disc while the vehicle is in motion. The effect leads to soft or inconsistent initial pedal travel meaning for a brief moment the car will not slow down.
There are a number of factors that influence this phenomenon with drivers hitting curbs and hard cornering on rough surfaces leading causes.
These cone shaped springs sit behind the calliper's pistons to help stabilize the knock back on both front and rear calipers.
Recommended for all types of competition use.
FRONT AND REAR CALIPERS