51720-38110FFF
51720-38110FFF
Hyundai, Kia
2005, 2004, 2003, 2002
Chassis System
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Product Description
The 51720-38110FFF is a first-generation integral front wheel hub bearing assembly built for Hyundai Sonata EF and Kia Optima/Magentis MS models produced between 2002 and 2005. This pressed hub unit integrates double-row angular contact bearings and a magnetic ABS encoder ring, supporting consistent operation of electronic stability control and traction control systems. Manufacturing takes place in IATF16949-certified facilities, aligned with tier-supplier specifications established by NSK and FAG. Minimum order quantities start at 500 units, suitable for drivetrain component distributors, aftermarket parts programs, and service operators supporting older vehicle parcels.
Parameter | Detail |
OE Number | 51720-38110FFF |
Official OEM Name | BEARING ASSY-WHEEL HUB / WHEEL HUB BEARING ASSEMBLY (GEN 1 INTEGRAL TYPE) |
Interchange OEM Numbers | 51720-38110FFF, 51720-38111, 51720-38110, HA590210, BR930450 |
Applicable Vehicles | Hyundai Sonata EF, Kia Optima/Magentis MS (Early Gen) (2002-2005) |
Hub Generation | First-generation (Gen 1) integral hub unit with non-serviceable pressed double-row angular contact bearings |
Mount Position | Front wheel steering knuckle spindle (LH or RH as designated) |
ABS Sensor Integration | Exciter tone ring (magnetic encoder ring) integrated into hub seal for active ABS wheel speed sensing |
Bolt Pattern | 4×114.3mm PCD (4-lug) or 5×114.3mm PCD (5-lug) per OE specification |
Wheel Stud Configuration | 4 or 5 studs (M12 × 1.5 thread) with captive press-fit design |
Hub Flange Diameter | Approx 145-155 mm |
Bearing Bore ID (spindle mount) | Approx 42-48 mm |
Overall Hub Height | Approx 75-90 mm |
Net Weight per Unit | Approx 3.2-4.5 kg (7.1-9.9 lbs) |
Package Size | 180 × 180 × 110 mm with rust-preventive wrapping |
Hub Flange Material | Forged medium-carbon steel (SAE 1045 equivalent) with zinc-phosphate + e-coat corrosion protection |
Wheel Stud Material | Carbon steel with rolled threads (press-fitted into hub flange) |
Bearing Race Material | Case-hardened through-hardened bearing steel (60-64 HRC) |
Rolling Elements | Precision grade 10 chrome steel balls or tapered rollers (double-row arrangement) |
Seal Configuration | Dual-lip nitrile rubber seals with integrated ABS encoder ring (magnetic multipole or variable reluctance) |
Spindle Mounting Method | Interference fit (press-fit) onto steering knuckle spindle |
Production Standard | Assembled to NSK/FAG/SKF tier supplier specification for Hyundai-Kia OEM hub program; compliant with IATF16949 wheel bearing quality certification |
Torque Spec (hub-to-knuckle mounting bolts) | 85-110 Nm (check specific vehicle service data) |
Alternative Aftermarket Part Numbers | HUB-FRT-GEN1, WHB-10FFF, BEAR-51720-38 |
The integral hub unit houses two rows of angular contact rolling elements arranged to share combined radial and axial loads generated during cornering, braking, and acceleration. This dual-row configuration delivers higher load capacity compared to single-row tapered roller designs, matching the load requirements of front wheels that perform steering, braking, and driving functions simultaneously. Bearing races receive case-hardening treatment to reach 60-64 HRC surface hardness, supporting wear resistance under regular operating conditions.
The hub flange receives three layers of corrosion protection: zinc phosphate conversion coating, cathodic electro-deposit primer, and a topcoat finish. Wheel studs use rolled thread construction rather than cut threads, supporting consistent fastener strength and nut engagement. The press-fit stud design reduces loosening under repeated wheel removal and installation cycles.
Dual-lip nitrile rubber seals create a barrier against water, dust, and road debris intrusion. A magnetic encoder ring is integrated into the outboard seal assembly, generating an AC signal as the hub rotates. This signal is picked up by the fixed ABS speed sensor, delivering wheel velocity data to the ABS module, traction control system, electronic stability program, and cruise control system.
A properly functioning hub bearing assembly maintains consistent wheel position, reduces vibration and noise during vehicle operation, and supports accurate wheel speed signal transmission for vehicle control systems. Worn or damaged bearings may produce low-pitched growling or humming noise that increases with vehicle speed, trigger dashboard warning lights for ABS and stability control systems, or create excessive wheel play that affects steering feel. Installation requires a specialized hub puller and press tool; professional installation is recommended.
This issue most often stems from worn or pitted bearing races due to metal fatigue, contamination from failed seals, insufficient lubrication, or impact damage from pothole or curb strikes. Diagnosis involves identifying speed-dependent noise that changes pitch during turns, spinning the wheel by hand to detect roughness, and checking for play at the 12 and 6 o’clock tire positions. Resolution requires replacement of the complete hub assembly, as individual bearing components are not serviceable. Installation steps include cleaning the knuckle mounting surface, applying anti-seize compound to hub splines and mounting surfaces, torquing the axle nut to 230-280 N·m, and torquing hub mounting bolts to 90-110 N·m in a crisscross pattern. Axle nuts should be replaced with new units rather than reused.
This fault typically arises from a damaged magnetic encoder ring, metallic debris buildup on the encoder surface, or corrosion between the hub and sensor bracket. Diagnosis uses scan tools to retrieve wheel speed sensor circuit codes and verify inconsistent sensor readings. Resolution requires replacement of the complete hub assembly, as the encoder ring is integrated and non-serviceable. Additional steps include cleaning the wheel speed sensor and mounting surface, clearing fault codes, and conducting a road test above 20 km/h to confirm consistent readings.
This condition results from severely worn bearings or broken internal bearing cages, creating excessive radial and axial movement. Symptoms include noticeable wheel wobble when lifted, unstable handling during lane changes, and grinding noise at low speeds. Operators should not drive vehicles with loose wheel bearings due to the risk of wheel separation. Resolution requires immediate hub assembly replacement, along with inspection of the steering knuckle for damage before installation.
This is an aftermarket replacement manufactured to meet or exceed OEM specifications. It matches the fit, form, and function of the original equipment part, with pricing structured for aftermarket procurement programs.
This part fits Hyundai Sonata EF and Kia Optima/Magentis MS models from 2002 to 2005. For vehicles not listed, contact customer support with a VIN for fit verification.
Standard automotive hand tools support most installation steps. A torque wrench is required to tighten fasteners to factory specifications. A hub press and puller are required for removal and installation of the pressed hub unit. Refer to the vehicle-specific service manual for complete procedures.
Warranty coverage follows the published company policy, applying to manufacturing defects under normal use conditions. Improper installation, competition use, or modifications void warranty coverage.
Replacing paired wear items (both left and right sides, associated seals, and fluids) during the same service is recommended to support balanced operation and reduce repeated labor costs.
Cross-reference the OEM part number 51720-38110FFF with your vehicle VIN through an authorized dealer or online compatibility checker. OEM part numbers provide the most accurate fit verification.
Minimum order quantities range from 500 to 1000 units for commercial procurement orders. Two packaging categories are available: genuine MOBIS standard packaging, and aftermarket packaging including neutral packaging and custom brand packaging. Orders are suited for drivetrain specialists, aftermarket parts distributors, and fleet service operations.
