The training wheels came off yesterday. And it's pretty awesome.
He learned how to ride without training wheels at the end of the summer on his older, much smaller bike. But he couldn't get comfortable on this bigger bike. So we put the training wheels on and have been riding a lot lately. I have been asking for weeks (months) if he was ready, but he always said no. So Saturday we met friends who were also ready to take their training wheels off. Something about the peer pressure or the barometric pressure that day because he was ready.
Several people have likened this to potty training, "When they're ready, they're ready." Fortunately, this didn't involve any missteps that included bowel movements in sweaty boys underwear.