The parts necessary for gear drive using OD2588 multi-purpose aluminum rear bulkhead are set. The counter gear is 27T, the differential gear is 54T, and the secondary reduction ratio is 2.0. The combination of lightweight aluminum rigid axles provides strong traction performance. It is also possible to combine floating motor mounts. In addition, the secondary reduction ratio can be set to 14 patterns in the range of 2.70 to 1.64 by using the optional counter gear set. It can be easily adapted to different road surfaces, courses and driving styles. The gears are common to those for XEX, and ball differentials can be used for both Diaval and XEX.