These caster blocks add 5 degrees to the caster provided by the arm kick-up. So on a standard RC10 with 30-degrees of kick-up, the resulting caster with these is 35 degrees. These could be used with our 25 degree RC10 front arm mounts to achieve 25 degrees of kick-up and 30 degrees of caster. This is a popular front end configuration on modern buggies run on high traction surfaces.