Tie Rod Ends (better: tie rod joints) are almost always angle ball joints or universal joints.
The upper and lower Tie Rod End shell can be made of steel, plastic or a combination of both materials. Tie Rod End with plastic shells are made of polyethylene, for instance. The friction pairing results from the shell material and the ball surface. The moments (torque, motive torque, initial break-away torque) and the compliance, the ball play (better: the stroke) derive from the friction pairing. Tie Rod End with steel shell constructions provide an extremely low compliance both in radial and axial direction. Tie Rod End with High-grade plastic shell materials also provide a low compliance coupled with excellent anti-friction characteristics and excellent damping. The drawing of Tie Rod End shows a joint neck with inside thread bore. The joint is protected by means of a rubber bellow.