Nexx Racing's Optional/Replacement REAR, 11mm Treaded, Racing RADIAL TIRES. RS1; SOFT, Compound, RM1; Medium Compounds. These are EXCELLENT tires, used by professionals, all over the world. Nexx Racing's commitment to your satisfaction is to package (4) tires per package for just $6.99 and to provide tire selection for all class's of racers, chassis and levels, get your today!