30mm ID Metric TC Oil Seal | R23 Double Lip NBR Rotary Shaft Seal

Measure three dimensions: shaft diameter (inner diameter = 30mm for this seal), housing bore diameter (outer diameter), and housing depth (height/width). All three must match. This listing covers a fixed 30mm (≈1.18″) ID with OD options from 40mm to 56mm and heights from 5mm to 12mm. If replacing an existing seal, the dimensions are typically stamped on the old seal's face or listed in your equipment's parts manual.

TC (also called R23 or double-lip) seals have two sealing lips: a primary spring-loaded lip that retains lubricant and a secondary dust exclusion lip that blocks contaminants from entering the housing. SC (single-lip / R21) seals have only the primary lip. TC seals generally provide better protection in environments with dirt, dust, or moisture — making them the more common choice for automotive and agricultural applications.

Metric TC oil seals are generally designed for low-to-moderate pressure applications — typically up to about 0.3 bar (≈4.4 psi) dynamic pressure. They are not intended for high-pressure hydraulic circuits. For exact pressure ratings for your specific OD/height combination, contact us to confirm.

NBR (nitrile rubber) offers good resistance to petroleum-based oils, greases, and water splash, making it generally suitable for outdoor use in moderate conditions. However, NBR is not recommended for prolonged exposure to ozone, UV radiation, or certain synthetic fluids such as phosphate esters. For harsh outdoor or aggressive chemical environments, a Viton (FKM) seal may be more appropriate — contact us if you need guidance.

These seals conform to the metric R23 / TC standard (ISO 6194-1 / DIN 3760 Type AS) and are compatible with metric shafts with a 30mm diameter. For optimal sealing life, the shaft surface finish should typically be Ra 0.2–0.8 µm (8–32 µin). Shafts with grooves, corrosion, or excessive runout may reduce seal life regardless of seal quality.

The outer diameter must match your housing bore and the height (width) must fit within your housing depth. Available ODs in this listing range from 40mm (≈1.57″) to 56mm (≈2.20″) and heights from 5mm (≈0.20″) to 12mm (≈0.47″). If you are replacing an existing seal, the three dimensions are typically stamped on the old seal's face or listed in your equipment's parts catalog. Select the matching combination from the variant dropdown above.

NBR seals are generally compatible with mineral-based oils and many conventional gear oils. Compatibility with fully synthetic PAO or ester-based oils varies — in most cases NBR performs adequately for typical service intervals, but for long-term exposure to aggressive synthetics, verify compatibility or consider an FKM alternative. Contact us if you need guidance for a specific fluid type.

For a single repair, a pack of 1 or 2 is typically sufficient. If you are rebuilding a gearbox or differential with multiple shaft seals, a pack of 5 or 8 is generally more economical. Workshop and service shops often stock packs of 10–50 for common sizes to avoid delays on future jobs. Larger packs offer a lower per-unit cost.