81.45501.0077 Front Hub Bolt

Function, Specifications, Materials, and Key Parameters of 81.45501.0077 Wheel Bolt

1. Function

The 81.45501.0077 wheel bolt is a critical fastener used in automotive wheel assemblies, primarily in heavy-duty commercial vehicles such as those manufactured by Shaanxi Automobile Group (e.g., Delong series). Its main functions include:

• Securing the Wheel: It fastens the wheel to the hub, ensuring that the wheel remains firmly attached during vehicle operation.

• Transmitting Torque: It transfers torque from the axle to the wheel, enabling the vehicle to move.

• Withstanding Loads: It bears the vehicle's weight and dynamic loads during driving, including braking and cornering forces.

2. Specifications

• Part Number: 81.45501.0077

• Application: Specifically designed for heavy-duty trucks, such as Shaanxi Automobile's Delong series (e.g., M3000, X3000).

• Type: Wheel bolt with nut (may include washer in some configurations).

• Thread Type: Typically a metric thread (e.g., M22 or similar, depending on the exact specification).

• Thread Pitch: Varies based on design (e.g., 2.0 mm, 2.5 mm, etc.).

• Length: The overall length of the bolt, which must match the hub and wheel assembly requirements (e.g., 220 mm in some cases).

• Head Type: Hexagonal head for wrench/socket engagement.

3. Materials

• Bolt Material: Typically made from high-strength alloy steel (e.g., 40Cr, 42CrMo, or similar) to withstand high tensile and shear loads.

• Nut Material: Often made from the same or similar alloy steel for consistency and strength.

• Surface Treatment: May include zinc plating,Dacromet coating, or other corrosion-resistant finishes to protect against environmental factors.

4. Key Parameters

• Tensile Strength: The bolt must meet specific tensile strength requirements (e.g., Grade 10.9 or higher in the metric system).

• Yield Strength: The stress at which the bolt begins to deform plastically.

• Thread Engagement Length: The minimum length of thread that must engage with the nut or hub to ensure secure fastening.

• Torque Specification: The recommended torque value for tightening the bolt to ensure proper clamping force without over-tightening.

• Thread Fit: The class of fit between the bolt and nut (e.g., 6g/6H for metric threads).

• Head Dimensions: The width across flats (WAF) and height of the hexagonal head for tool compatibility.

5. English Terminology

• Wheel Bolt: Also referred to as a wheel stud or hub bolt in some contexts.

• Hexagonal Head: A six-sided head designed for engagement with a wrench or socket.

• Tensile Strength: The maximum stress a material can withstand while being stretched or pulled before breaking.

• Yield Strength: The stress at which a material begins to deform plastically.

• Thread Pitch: The distance between adjacent threads, measured in millimeters (for metric threads).

• Torque Specification: The recommended rotational force applied to tighten the bolt.