Porsche 996 TT Repair Manual page 840

A Spherical cap ring (permanently connected with the wheel bolt)
X Spherical cap bearing surface facing the wheel (do not grease)
Note
• Rework on wheel bolts is impermissible!
5. Always replace damaged wheel
bolts.
This damage includes mechanical damage to the thread, the spherical cap and damage resulting from seizure
of the bolt head bearing surface and spherical cap ring. It must be possible to rotate the spherical cap ring on
the bolt shank and to move it in the axial direction.
Note
• Always observe the specified tightening torque of 130 Nm (96 ftlb.)!
6. Screw in wheel bolts by hand and then tighten evenly. Start at the top when
tightening.
996420, 996421, 996450, 996451, 996620, 996621, 996650, 996651, 996840, 996841
Removing/installing the wheel on vehicle − Turbo and GT2
einordnung
777