NO S!
INFILL:
BOX_INTERNAL_BT1.STL: VASE MODE
OTHER PARTS: 15% or more
LAYER HEIGHT: 0.2 mm (BODY_BIG_TIRES_1.STL can be printed with a 0.1 mm layer height)
NOZZLE DIAMETER: 0.4 mm
MATERIAL: PETG, PLA, TIRES CAN BE PRINTED IN TPU / FLEX!
PERIMETERS: 2 (suggested value; more perimeters would just make the snap-fit connections stiffer)
The STL models are already in the correct orientation.
The prints presented were made on the Prusa MK4
IMPORTANT:
The monster truck model has 0.3 mm clearances between the walls of the print-in-place moving parts. This is not a demanding tolerance for a 3D printer. However, to be sure, you can print one of the "Clearance Tolerance Tests" available on the Internet. If, in your case, the walls of the elements are fused together with a 0.3 mm clearance, you should likely reduce the flow (extrusion multiplier) value or adjust the X/Y compensation ratio (Horizontal expansion) in your slicer (e.g. to -0.1 mm). Also, check if the diameter of the filament you are using is not too large and if your nozzle is not worn out.
The animation shows how to assemble the monster truck.
Once printed, rotate simultaneously one side (axle) of the suspension clockwise and the other counterclockwise. After a few times, the internal gear mechanism should start working smoothly if it wasn't initially.
When assembling the gift box, ensure that BOX_INTERNAL_BT1.STL is correctly oriented inside BOX_BOTTOM_BT1.STL (Look at the photo, pay attention to the groove on the side wall).
If you are printing, especially with PETG, without an enclosure, you can introduce a small brim or use a printing adhesive (e.g., Dimafix) for the gift box lid and bottom to reduce the risk of warping.
to clean the bed before printing to ensure high adhesion.
Update: I have ed an additional tire model "TIRE_S1B_looser_fit.STL" with a 50% looser fit for those who have fitting issues with the standard version.