Choose the right sort of bike for your kids. At 2 years old, most kids can start to ride on tricycles. Around 4 or 5, some children are able to start riding with removable training wheels and pedal brakes (hand brakes require more strength than young children have). Others need several more years before they are ready to go on two wheels. If your kid hasn't asked you about bikes and seems happy enough on his tricycle, leave well enough alone.