So after having tried all kinds of methods and after many tears and crashes, training wheels, no training wheels, running with little biker,etc...we've finally learned the secret!
I was recently searching on line for the best ways to teach children to ride on two wheels and learned that bikes with no pedals, which are often quite pricey, work amazingly well. My hubby also heard that the best way to teach adults and kids with special needs is to just take all the pedals and training wheels off.
We had kids "bike" by pushing with their feet in big "walking on the moon" steps. We made it a game to see how long they could balance without touching their feet to the ground. A few short weeks of practicing and they were balancing for about 10-20 seconds without touching the ground.
We put the pedals back on, and just like magic they all took off riding!
*Note:When removing the pedals, the left pedal is usually threaded differently than the right pedal to avoid unintentional unscrewing during riding. The LEFT pedal is RIGHTY-LOOSEY (clockwise), LEFTY-TIGHTY (counter-clockwise).