also not ideally suited to 20 inch wheels either. i’ve done a few runs with brooklyn jnr (so his dad can get some proper runs in) the kid has no fear, riding behind him through a little rock garden, he still gets thrown around a lot. when he disappeared at speed off the side of the track otb into a large bush, i feared the worst!
he got up pissed at himself for crashing :D
the brooklyn is a custom frame, also has a custom fork crown that runs on top of the head tube. the fork will be the hardest thing to get right.imo!
i’ve also seen the fs frank the welder made for his kids, also very nice. it was for sale for $600 but had 24 inch wheels
decent tyres are also a problem.
there is nothing available off the shelf. your gonna have to get something made or wait till your kids a little bigger…