Hub bolts are high-strength bolts that connect vehicle wheels. The connection position is the hub unit bearing of the wheel! General mini-car 10.9, large and medium-sized car 12.9! The structure of hub bolt is generally spline gear and threaded gear! And a hat! T-head hub bolts are mostly above grade 8.8, which bear the high torque connection between automobile hub and axle! Most of the double-headed hub bolts are above grade 4.8, which bear the connection between the hub shell and the tire, and the torque is light.