What is the part I have lost underneath my S80 ?
 

I rode on the sidewalk and I lost something underneath the car. A piece fell, and some now shines (picture 1). Now, the rim of the wheel rubs when I turn the wheels. On the picture you can see the edge of the rim that shines as she rubbed. (picture 2). What is the part that I have lost ?
http://sergi5.com/volvofrottement/IMG_4052.JPG
http://sergi5.com/volvofrottement/IMG_4051.JPG