Product Overview

The DAC series represents the most widely used first-generation Hub Bearing unit, featuring a double-row angular contact ball design arranged back-to-back (DB). These bearings utilize integrated inner and outer rings and incorporate double-sided rubber seals; they are pre-filled with specialized grease and have preset axial clearance at the factory, requiring no adjustment upon installation. Utilizing steel balls as rolling elements—which maintain point contact with the raceways—the series achieves a friction coefficient of only 0.001–0.002. Key advantages include high rotational speeds, smooth operation, low noise, and minimal frictional resistance, making them the dominant choice for passenger vehicles. They are categorized into four size ranges based on inner diameter—small (25–32 mm), compact (34–38 mm), medium (40–42 mm), and large (45–50 mm)—thereby meeting the requirements of all passenger vehicle types, from micro-cars to mid-to-large SUVs. 

Key Features

Low Friction, High Speed: The point-contact design minimizes frictional resistance, allowing for higher operating speeds (approximately 2000 rpm in typical wheel applications), which benefits fuel economy and extends the range of electric vehicles.

Double-Row Combined Load Capacity: Two rows of steel balls arranged back-to-back simultaneously support radial and bidirectional axial loads, accommodating the complex forces encountered during vehicle operation.

Integrated Sealing & Maintenance-Free: Double-sided Nitrile Rubber (NBR) sealing lips with a metal core effectively block mud, water, and dust; pre-filled with grease at the factory, requiring no additional lubrication or maintenance during the normal service life.

Factory-Preset Internal Clearance: Axial clearance is precisely set during production, eliminating errors associated with manual on-site adjustments and ensuring consistent installation quality.

Smooth, Quiet Operation: Minimal vibration from rolling steel balls makes it suitable for passenger vehicles with strict NVH (Noise, Vibration, and Harshness) requirements.

High Cost-Effectiveness: Features a mature design and is produced in large volumes, resulting in economical aftermarket pricing and low replacement costs.

Model Dimensions

DAC models follow the naming conventions of the JB/T 10238 standard: `DAC + Inner Diameter (2 digits) + Outer Diameter (3 digits) + Width (2 digits)`. For example, `DAC35650035` indicates an inner diameter of 35 mm, an outer diameter of 65 mm, and a width of 35 mm. 

Suffix Explanations

DAC: Type code for double-row angular contact ball hub bearing units.

Numeric sequence: First 2 digits indicate inner diameter *d* (mm); middle 3 digits indicate outer diameter *D* (mm, padded with a leading zero if under 100); last 2 digits indicate width *B* (mm).

2RS / ZZ: Indicate double-sided rubber seals and metal dust shields, respectively; Hub Bearings typically come with rubber seals by default.

A / B / E suffixes: Indicate improved designs or variants meeting specific OEM specifications, featuring differences in internal clearance, cage design, or seal type.

Magnetic encoder version: Some models feature an integrated multipole magnetic ring within the seal to provide wheel speed signals for ABS/ESP systems; these are marked with specific suffixes.

Widths differing on each side are separated by a slash (e.g., `DAC30600035/37`).

Application Scenarios

The DAC series is widely used across various passenger vehicle segments: rear wheels of micro and small cars; front and rear wheels of compact cars; front and rear wheels of mid-sized sedans and urban SUVs; and front and rear wheels of large sedans and heavy-duty SUVs/MPVs. New Energy Vehicles (NEVs) also commonly utilize DAC Ball Bearings due to their requirements for low friction and lightweight construction. Additionally, this series is used in the front wheels of certain light commercial vehicles and in low-speed electric vehicles. 

Selection Recommendations

Prioritize matching by OEM number: The most reliable method is to cross-reference the model number stamped on the original bearing or the OEM part number from the service manual, as different model years of the same vehicle may use different specifications.

Verify dimensions: Inner diameter, outer diameter, and width must match exactly; pay special attention to the fact that bearings with the same inner and outer diameters may come in multiple width variations.

Distinguish between driven and non-driven wheels: For front-wheel-drive vehicles, the inner race of the front wheel bearing features a splined bore, whereas the rear wheel bearing has a smooth bore; these specifications are not interchangeable.

Check for ABS magnetic rings: For vehicles equipped with ABS/ESP, some rear wheel bearings feature an integrated magnetic encoder; when replacing, verify the presence of the magnetic ring and the orientation of the magnetic poles.

Replace in pairs: It is recommended to replace bearings on both the left and right sides of the same axle simultaneously to avoid uneven wear between old and new bearings.

Installation standards: Use a specialized sleeve during press-fitting, applying pressure only to the face of the appropriate bearing race; never strike the rolling elements or seals directly. Tighten the axle nut to the vehicle manufacturer's specified torque (typically 180–280 N·m).