Definition: The foam inserts that fit inside some RC tires and help them keep their shape are known as inner foams.
Inner foams in an RC tire can be changed out for softer or more firm foam to improve traction on different surfaces. Some types of tires, especially softer tires with high tire walls, would tend to sink in and lose traction without tire inserts. When left sitting on a shelf for an extended period of time tires without inner foams may get flat on the bottom.
Also Known As: foam insert | tire insert