SKF
Hub Bearing Unit Seals for Heavy Duty and Light Vehicles
SKF hub bearing unit seals are engineered for the wheel ends of both heavy-duty trucks and light passenger vehicles. They are typically integrated into the hub bearing unit (HBU) as a pre-assembled, non-serviceable component. Heavy-duty versions use robust cassette seal modules with multiple dust lips and labyrinth stages to exclude mud, water, and road de-icing chemicals, enduring extreme wheel loads and brake-induced heat. Light vehicle versions emphasize low friction and often embed a magnetic encoder ring for wheel speed sensing (ABS). SKF’s material choices (FKM, HNBR, or ACM for lip elements; NBR for secondary dust lips) and lip geometry are validated through extensive rig testing simulating vehicle life. A reliable hub seal is critical for wheel bearing life, braking safety, and vehicle stability system accuracy.
Send an Enquiry
We'll get back to you on WhatsApp.
Trusted by Industry Leaders
Cassette Architecture (Heavy)
Multi‑lip and labyrinth for extreme mud and water.
Low‑Friction PTFE Lip (Light)
Minimises drag for EV range and fuel economy.
Integrated ABS Encoder
Magnetic ring within the seal for wheel speed sensing.
Axial Float Tolerance
Seals accommodate the bearing unit’s internal clearance changes.
Salt‑Spray Corrosion Resistance
Stainless steel or coated cases survive winter road treatment.
Pre‑Greased and Ready‑to‑Assemble
Simplifies vehicle production and aftermarket replacement.
Why Heavy‑Duty Hub Seals Use Multiple Lips
A single lip operating in muddy, high‑pressure‑wash environments will be quickly undermined. A three‑lip cassette provides a primary oil lip, a secondary dust lip, and a tertiary labyrinth, creating three sequential barriers. The space between the lips is factory‑filled with grease, acting as a contaminant trap.
The ABS Encoder Ring: Precision Inside the Seal
The magnetic encoder is vulcanised into the seal body. Its pole pairs are precisely aligned and calibrated to deliver the required signal amplitude to the ABS module. Any defect in this encoder — a missing pole or weak magnetisation — would illuminate the ABS warning light. SKF’s 100% end‑of‑line testing ensures every encoder seal meets the signal specification.