Once your child tackles hillier terrain, gears bicycles are the best option. By the time kids are ready for a 20-inch bike (around 6 years old), they have a heightened sense of interest and ability and can comfortably ride a geared bicycle. Therefore, Tru bikes offer both gear bicycles for 6 – 8 years kids as well as without gear cycle for kids 6 – 8 years. Super comfortable and stylish kids bikes.