07/02/2014 How does the Bunzi seat adjust ? The Bunzi seat “grows” with your child in that sense that the seat position in 3-wheel mode is low for comfort and ease of use (learning to get on and off), and in 2-wheel mode it is slightly higher for more speed and ergonomics. So it actually grows with the development of the child. Don’t worry, in this young phase (between 1-3 years) the seat height is less important for performance. The main objective is to be safe and close to the ground to feel comfortable and stimulate learning. Seat height in 3-wheel mode is 22cm. Seat height in 2-wheel mode is 25cm.