I used a variant of a method that I saw on the Bicycling magazine website for both of my boys. I was plenty frustrated at first until they suddenly “got it”. Once you get them to that point where everything clicks the satisfaction will quickly overcome all the frustration that you have experienced. Try to keep the whole experience relaxed for him, as hard as that is. Fear of falling and pressure to learn seem to be the biggest roadblocks to learning from what I have seen.

What to do: Basically, you take off the training wheels, lower the saddle so that he can rest both feet flat on the ground, then find a smooth & grassy field w/ a gentle slope (the longer the better). My boys wore elbow pads, knee pads, & a helmet (of course) and I showed them how it didn’t hurt to fall on the grass. Go to the top of the slope & hold the handlebar w/ one hand and the back of the seat w/ the other while your son gets on the bike and puts his feet on the pedals. When he is ready, start him going down the hill while you hold on to the bike. Once you have done this a couple of times and he is comfortable pedaling, let go when he seems to be well balanced. Praise him up and down for any amount of riding he is able to do on his own without your help. Once he overcomes his fear and is able to do it on his own you can gradually work the seat up to where it needs to be. It takes a little while for things to click, but once they do he will progress quickly.