Metric TC Oil Seal Double Lip w/ Spring — NBR Shaft Seal ID 25–30mm

Use a caliper to measure three dimensions: (1) the shaft outer diameter — this is your seal ID; (2) the housing bore inner diameter — this is your seal OD; (3) the housing depth — this is your seal width. Match all three to the variant label. For example, a 30×50×10mm seal fits a 30mm shaft, a 50mm bore, and a 10mm deep housing. When converting: 25mm ≈ 0.98", 28mm ≈ 1.10", 30mm ≈ 1.18".

TC is an industry-standard designation for a double-lip oil seal with an integrated garter spring. The primary lip seals lubricant in; the secondary lip keeps dirt and moisture out. The garter spring maintains consistent lip-to-shaft contact pressure throughout the seal's service life. TC seals are the most common type used in gearboxes, axles, and rotating shaft applications.

TC-type NBR oil seals are generally designed for low-to-moderate pressure rotary applications, typically up to 0.3 bar (≈4.4 psi) dynamic pressure. They are not suitable for high-pressure hydraulic lines. If your application involves significant back-pressure, a different seal type (such as a lip seal with a backup ring) may be required — contact us to confirm.

NBR nitrile rubber generally performs well in outdoor and wet environments, resisting water, mud, and petroleum-based fluids. The secondary dust lip on TC seals provides additional protection against ingress. However, NBR is not recommended for prolonged exposure to ozone, direct UV, or aromatic/halogenated solvents. For extreme outdoor or chemical environments, VITON (FKM) seals are typically a better choice.

NBR is generally compatible with: petroleum-based engine oils, gear oils, hydraulic fluids (mineral-based), water, and most greases. NBR is typically not compatible with: DOT 3/4 brake fluid, phosphate ester hydraulic fluids, ketones, esters, and aromatic fuels. If you are unsure about your specific fluid, contact us to confirm before ordering.

For best sealing performance, the shaft surface in the contact zone should generally have a finish of Ra 0.2–0.8 µm (8–32 µin). A surface that is too rough accelerates lip wear; one that is too smooth may not retain a thin lubricating film under the lip. Avoid installing over keyways, splines, threads, or sharp edges — use an installation sleeve if necessary.

Apply a thin film of clean oil or compatible grease to the seal lip and the shaft surface before installation. Use a proper seal driver or a flat wooden block to press the seal in squarely and evenly — never strike the seal face directly with a hammer. Press until the seal is flush with or just below the housing face. Avoid dragging the lip over keyways or threads during installation.

TC oil seals are generally interchangeable across manufacturers when the ID, OD, and width dimensions match exactly. The TC profile is an industry-standard design. In most cases, a 30×50×10mm TC seal from any manufacturer will fit the same application — confirm dimensions before installation.