The Kinderkraft balance bike has become slightly small for my daughter, plus the 3 wheels are almost a limit for her balance.
So I decided to modify the front, eliminating a wheel and raising it slightly.

You have to swap the closed wheel cover of the wheel you want to use with the open one of the other. It is sufficient to pry with a small screwdriver.

The hardware required for assembly is:
-70mm M8 threaded pin (engraved to be screwed in with a flathead screwdriver)
-35mm M6 threaded screw (40mm if you want to put a lock nut)

I also increased the saddle height.

Printed at 0.20mm
With supports
PLA
4 perimeters
5 lower and upper layers
Grid Fill 25%