SB2 Oil Seals - Durus

What Is a SB2 Oil Seal?

SB2 adds an auxiliary dust lip to the standard SB configuration: Type B bare-metal case combined with S-style primary sealing lip plus auxiliary lip for contamination exclusion. The result is dust exclusion in a metal-case construction - preferred over TC when the housing is hard-bored and the rubber coating is unnecessary. SB2 fills the gap between SB (single lip, clean only) and TC (full rubber coat, all conditions).

Construction summary:
Case Type: B (bare metal)
Lip Configuration: S-style with auxiliary lip

When to Choose SB2

• Hard precision-bored housings combined with dusty operating environments
• Heavy industrial gearbox external shaft positions in cast iron housings
• Replacement for failing SB seals where dust contamination caused original failure
• Cost-optimized applications where TC's rubber coat is unnecessary but dust exclusion is required

When NOT to Choose SB2

• Soft housings (aluminum) - choose SC or TC with rubber coat instead
• Verified clean environments where SB single lip is adequate
• Severe contamination requiring full double-lip TC for maximum protection

Related Seal Types

Frequently Asked Questions

What is the difference between SB and SB2 oil seals?

Both use the same Type B bare-metal case construction with S-style primary sealing lip. The difference is the auxiliary lip. SB has only the primary lip - appropriate for clean environments. SB2 adds an auxiliary dust lip outboard of the primary, providing contamination exclusion in dusty operating conditions while keeping the bare-metal case construction. The "2" suffix in Durus designations indicates the addition of an auxiliary lip.

When should I specify SB2 instead of TC?

Specify SB2 when the housing is hard material (cast iron, steel) with a precision-bored seal cavity that doesn't require the bore-tolerance accommodation of TC's rubber coating, but the operating environment exposes the seal to dust. SB2 provides equivalent dust exclusion to TC at typically lower cost due to the simpler bare-metal case. For soft housings or variable bore tolerance, TC remains the better choice.

Is SB2 interchangeable with SKF or CR equivalents?

SB2 is functionally equivalent to manufacturers' "single lip with dust lip, bare metal case" designations - including CR HMS5 in some variants and SKF "BAUSL" series. Cross-reference is dimension-based (shaft × bore × width) plus case + lip construction match. Texas Belting can cross-reference any equivalent part number from major manufacturers - provide the original part number for a Durus SB2 equivalent.

What is the friction difference between SB2 and TC seals?

SB2 and TC have similar total friction since both have two lips (primary + dust lip) contacting the shaft. The friction difference comes from the lip design: TC's Standard primary lip and SB2's S-style primary lip are engineered for slightly different load characteristics. In practice, both generate comparable shaft drag and heat. For applications where lip friction is critical (high-speed shafts), reduce to single lip configurations (SB or TB) and verify dust exposure is not an issue.