What are the recommended child bike sizes for different age groups?

The recommended child bike sizes for different age groups are as follows:

• 2-4 years old: 12-inch wheel size
• 4-6 years old: 14-inch wheel size
• 6-9 years old: 16-inch wheel size
• 9-12 years old: 20-inch wheel size

It is important to ensure that the child can comfortably reach the handlebars and pedals while sitting on the bike.