4WD truggy shocks with 40x3.2mm rod

This is the second version that work. To get a good print, rotate if necessary. The diameter of the springs must be 15mm.
The rod sits firmly and does not easily come off. I also cut a few lines of shallow threads at the end of the rod to improve the grip.

The halves are held together by the spring. The rod ensures smooth linear motion along with holding the construction straight.

v2a is strengthened with chamfer at the ends