It’s done, just like when he finally walked there were no mishaps, starting, stopping, not tippy at all. We have been biking to school (about 1 mile) since classes started. It has been really good practice for him. The past 6 weeks I have been calling him Stealth Rider; when he rides on 2 wheels only I can’t hear him behind me.
(Bribery was a factor in this achievement.)