Rotary Shaft Oil Seal TC/FB NBR Nitrile | 8mm-65mm ID | 1-3 Pcs

Measure three dimensions: the shaft diameter (this becomes the seal ID), the housing bore diameter (this becomes the seal OD), and the groove depth (this becomes the seal height). All three must match. For example, a 30 x 47 x 8mm seal fits a 30mm (≈1.18") shaft, a 47mm (≈1.85") housing bore, and an 8mm (≈0.31") groove. When converting: divide mm by 25.4 to get inches. Measure twice before ordering.

TC (also called TG4 or double-lip) seals have two sealing lips — a primary lip that retains oil and a secondary dust-exclusion lip. FB seals are a single-lip variant. TC seals are generally preferred for applications where both oil retention and contamination exclusion matter, such as gearboxes, pumps, and wheel hubs. Both types in this listing share the same outer dimensions.

Rotary shaft lip seals are designed for low-to-moderate pressure applications. They are typically rated for static pressures up to around 0.3 bar (≈4 psi) and are not intended for high-pressure hydraulic circuits. For higher-pressure sealing, a rotary face seal or O-ring energized seal is generally required. These seals are well-suited for gearboxes, differentials, pumps, and small engines operating at normal working pressures.

NBR nitrile rubber performs well in environments exposed to water, oil, and mild chemicals, making it generally suitable for outdoor use in moderate climates. However, NBR is not recommended for prolonged exposure to ozone, direct UV radiation, or ketone-based fluids. For extreme outdoor or chemical exposure, FKM (Viton) seals are typically a better choice. The TC double-lip design provides an added layer of protection against water and dust ingress.

NBR lip seals typically operate in a temperature range of approximately -40°F to +250°F (-40°C to +120°C). Shaft surface speed compatibility depends on shaft finish and lubrication, but NBR seals are generally suitable for shaft speeds up to around 4–6 m/s under normal lubricated conditions. A smooth shaft surface finish (typically Ra 0.2–0.8 µm) is recommended for optimal seal life. Consult your application specs to confirm suitability.

All dimensions listed are metric (mm). To find the equivalent inch size, divide by 25.4. For example, a 25mm ID ≈ 0.984" and a 40mm OD ≈ 1.575". These seals follow standard metric shaft seal dimensions and are compatible with any shaft machined to the corresponding metric tolerance. If your shaft is imperial, measure the actual diameter in mm and match to the closest seal ID.

NBR nitrile rubber is compatible with petroleum-based oils, hydraulic fluids, gear oils, greases, water, and many dilute acids and bases. It is generally not compatible with aromatic hydrocarbons, ketones, esters, or brake fluids. Always verify fluid compatibility with your specific application before installation. If you are sealing against synthetic esters or aggressive chemicals, consider an FKM (Viton) alternative.