Once it has been installed, the angle of the child seat varies according to its angle and shape. It is generally advisable for the child to be sitting as upright as possible in the event of a collision (because the collision forces are then dissipated more evenly throughout the body).
However, if the child is sitting too upright, its head will roll forwards. This problem may be resolved by installing the seat so tightly that some of the air in the padding – and thus, the improper angle/shape – is removed: Remove the locking bolt on the support leg. Place one hand on top of the seat and press firmly so that the support leg is shortened by a notch or two. Tighten with a ratchet (and anchor belts, if it is a belt-installed seat) so that the support leg is resting firmly on the floor and the seat is completely rigid. Replace the locking bolt. Start the installation from scratch, if necessary.