A variety of piston knockback springs are available for StopTech Racing calipers.
Flexing of the corner assembly can push the piston/brake pad back into the caliper body (knock back.) At the next braking event, a period of limited to absent braking can result while the piston/pad travels the gap caused by the “knock back”.
To prevent this, knock-back springs of varying force can be installed behind each caliper piston to resist the knock back occurrence.