Sphere Collider and Cylinder collider different shapes and sizes to my objects

Total newbie here! I am rezing my 3D cylinder and spheres but when I do the cylinder collider and sphere collider shape is not the same size as the object. So when things bump into my objects it looks really wierd, as if they are colliding too early and into thin air, not actually colliding into the object. Help! What am I doing wrong?! All I am doing is using the transform tools to change the shape of the object.

The colliders have offset, radius and size you can adjust.