The CR Oil Seal 3.250x8.250x0.531 SYN NBR is designed for industrial rotary shaft applications requiring dependable lubricant retention around a 3.250-inch shaft within a substantially larger 8.250-inch housing bore.

Installed between the rotating shaft and stationary housing, the sealing element creates controlled radial contact with the shaft surface. This helps reduce leakage of compatible oil or grease while protecting bearings, gearboxes, pumps, transmissions, and other internal rotating components from external contamination.

The product is identified by the CR manufacturer designation SYN. This is a manufacturer-specific profile code and should not be interpreted solely from the letters. The exact cross-section, sealing-lip geometry, number of sealing elements, reinforcement arrangement, outside-case construction, spring configuration, dust-exclusion feature, internal support structure, and installation orientation must be verified against the original seal or technical drawing.

Manufactured from NBR (Nitrile Butadiene Rubber), the sealing element is generally compatible with:

• Mineral oils
• Gear oils
• Hydraulic oils
• Bearing grease
• Petroleum-based lubricants
• General industrial lubricating fluids

NBR provides good resistance to petroleum-based oils, grease, abrasion, and mechanical wear under standard industrial operating conditions. Compatibility should be confirmed before use with aggressive chemicals, fuels, high continuous temperatures, ozone-rich environments, or specialized synthetic lubricants.

The inch dimensions convert approximately to:

Shaft diameter: 3.250 inches or 82.55 mm

Housing diameter: 8.250 inches or 209.55 mm

Seal width: 0.531 inch or approximately 13.49 mm

The unusually large difference between the shaft diameter and housing diameter indicates a specialized broad-section sealing assembly rather than a conventional compact radial oil seal. Accurate verification of the original SYN cross-section, support structure, installation depth, orientation, and housing geometry is essential before replacement.

⚙️ Applications

• Heavy industrial gearboxes
• Large bearing housings
• Industrial pumps
• Mechanical transmissions
• Process machinery
• Agricultural machinery
• Construction equipment
• Conveyor drive systems
• Legacy industrial equipment
• OEM rotating machinery

🎯 Benefits

✔ Helps retain compatible oil or grease

✔ Protects bearings and internal components

✔ Oil-resistant NBR sealing material

✔ Suitable for 3.250-inch shaft assemblies

✔ Specialized broad-section construction

✔ Good resistance to wear and abrasion

✔ Suitable for maintenance and overhaul work

✔ Supports legacy and specialized equipment

✔ Replacement ready when dimensions and profile match

🧠 Technical Insight

• CR SYN Seal Reference
• Large Inch-Size Rotary Shaft Seal
• NBR Sealing Material
• Manufacturer-Specific SYN Profile
• Broad Radial Cross-Section
• Low-Pressure Lubricant Retention
• Approximately 82.55 mm Shaft Diameter
• Exact SYN Cross-Section Must Be Verified

✅ Key Features

• CR Industrial Quality
• SYN Profile Reference
• Oil-Resistant NBR Material
• Specialized Reinforced or Composite Construction
• Inch-Size 3.250x8.250x0.531 Dimensions
• Suitable for Compatible Oil and Grease
• Heavy Industrial Replacement Seal
• Cross-Reference Support Available

📊 Specifications

Brand: CR

Model / Profile: SYN

Size: 3.250 × 8.250 × 0.531 inch

Metric Equivalent: Approximately 82.55 × 209.55 × 13.49 mm

Type: Specialized Large-Diameter Industrial Rotary Shaft Seal

Material: NBR (Nitrile Butadiene Rubber)

Construction: Manufacturer-Specific Reinforced or Composite SYN Shaft-Seal Arrangement

Lip Design: SYN profile; verify the exact geometry against the original seal or technical drawing

Dust Lip: Verify from the actual SYN cross-section

Spring Type: Verify from the actual seal construction

Internal Support: Verify the original support, carrier, spacer, or reinforcement arrangement

Shaft Diameter (ID): 3.250 inches / 82.55 mm

Housing Diameter (OD): 8.250 inches / 209.55 mm

Width: 0.531 inch / approximately 13.49 mm

Pressure Capability: Low-pressure rotary shaft-sealing service unless otherwise specified

Lubrication: Compatible oil and grease

Temperature Range: Typically approximately -30°C to +100°C for standard NBR; verify the actual compound, lubricant, speed, and operating conditions

Speed Consideration: Permissible speed depends on shaft diameter, lip geometry, surface finish, lubrication, temperature, alignment, and material compound

Application Class: Specialized Heavy Industrial Bearing and Rotating Equipment

Standard: Inch-Size Specialized Industrial Seal

🔁 Equivalent

Suitable replacement or cross-reference candidate for compatible:

• CR SYN Rotary Shaft Seal
• CR 3.250x8.250x0.531 Oil Seal
• 82.55x209.55x13.49 Rotary Seal
• 3.250-Inch Shaft Oil Seal
• Large-Housing NBR Shaft Seal
• Specialized Industrial Bearing Seal
• Heavy Gearbox Shaft Seal
• Large Pump Shaft Oil Seal
• OEM SYN Rotary Seal
• Broad-Section Industrial Oil Seal

The same dimensions alone do not guarantee interchangeability. The replacement must match the original SYN cross-section, sealing-element geometry, lip orientation, outside construction, reinforcement arrangement, internal support, spring configuration, installation direction, material compound, and operating requirements.

(Always verify dimensions, SYN-profile geometry, support construction, lip direction, shaft finish, housing condition, installation depth, lubricant compatibility, rotational speed, temperature, pressure, and operating conditions before ordering.)

📦 Availability

✅ In Stock

🚚 Fast Delivery Available

🌎 Worldwide Shipping Available

📦 MOQ: 1 Piece

🏭 Suitable for heavy gearbox overhaul, large bearing-housing maintenance, industrial pump repair, process-machinery servicing, agricultural-equipment repair, construction-equipment maintenance, legacy-equipment restoration, and compatible OEM replacement applications.

📲 Contact via LINE ID: dusitrea

📧 Email: sales@seal4go.com

💬 Technical support available before ordering

🔍 Assistance available for cross-reference and equivalent part identification