Double kingpin truck which fit Backfire Ranger X2 , X3 , Hammer and Hammer Sledge . The front Axle is the same for all three models with 9.5mm diameter (new front wheel with the 1614 bearings in the wheel), except the very 1st batch of Ranger X1 back in Nov. 2018 which was using the old front wheels with a square part.  The back axle now fits both Ranger x2 and X3. However, it is different from the batch before May 2020 (Orders of the Ranger X2 since early May 2020 received units with new motor axles that have a thicker square mounting point on the trucks. This is because we upgraded to 32kv motors from the old 28kv motors. This means the Ranger X2 had a little more torque than before)  The baseplates for the double kingpin truck are the same for both front and back.  The bushings inside the truck are stock bushings, with hardness close to 96A. Bushing color was orange in Ranger X2, and the bushing color was red or black in Ranger X3. There are no quality or hardness differences with two different colors. Bushings colors are black in Hammer and Hammer Sledge, the hardness is around 98A.  If there are production running changes in bushings colors, we will update again in the future.  Ranger truck axles do not fit the wheels with 608 bearings in G2, G3,G3 plus or Zealot Wheels.