My DS resisted this passionately; he was afraid the bike helmet clip would pinch his chin, he was afraid he'd fall, etc. He wept copiously when we removed the training wheels.
We really did push this (ours is the kind where you have to push him outside his comfort zone, then later he's pleased to have mastery). We had him count how many seconds he had ridden without training wheels. Counting was a way to keep his brain occupied and crowd out the fear a little, as well as a concrete way to track his progress. He cried a lot, but he learned how, and as it's an age-appropriate skill that he now enjoys, we're glad we forced the issue.
DeeDee
