You buy thisGross motor2–4 yrsOutdoors
Balance bike
No pedals, and that's exactly the point.

Balance bikeView on Amazon
Prep
0 min
Mess
None
How to play
Let him walk it first, for weeks if he needs to. Gliding comes on its own. Don't push him, and don't hold the seat.
What you need
A balance bike sized so both feet sit flat on the ground.
What it secretly builds
Gross motorBalancing is the hard part of cycling — pedalling is easy. Kids who learn this way usually skip training wheels entirely.
Safety first
Helmet from day one, and away from traffic.