Both boys have learnt on small bikes with training wheels but only have ever ridden on level concrete. They have each done several laps of Lemke Park Albany Creek in one go. 
This year I upgraded them to mountain bikes for size reasons however we are having difficulty with confidence on the change of bike. We have not yet learnt gear changes and aren't great with braking. Oscar has ridden the bike around the end of our cul-de-sac but no further.