Sg Oil Seal Size Chart and Replacement Guide
Sg Oil Seal Size Chart and Replacement Guide
To replace an Sg oil seal correctly, match the shaft diameter, housing bore diameter, and seal width in that order. These three dimensions are normally written as inside diameter × outside diameter × width, such as 30 × 52 × 7 mm, but the exact Sg profile and material must also be confirmed. I recommend measuring the installed seal and shaft directly, then checking operating temperature, fluid, speed, and pressure before ordering. At TEBIETE, I help buyers verify the complete specification rather than selecting a seal from dimensions alone.
This guide explains how to read an Sg oil seal size chart, identify a suitable replacement, avoid common measurement errors, and prepare a practical purchase inquiry. Because “Sg” naming can vary between manufacturers and catalogs, a size number should not be treated as a universal profile definition. The safest replacement is one that matches both the dimensional code and the construction required by the application.
Quick Summary for Sg Oil Seal Buyers
- Read the basic size as shaft diameter × housing bore diameter × seal width.
- Confirm whether the seal has a spring, dust lip, metal case, rubber-covered exterior, or other profile feature.
- Match the elastomer to the working fluid and temperature instead of choosing material by price alone.
- Check shaft condition, housing condition, rotation direction, speed, pressure, and installation space.
- Send TEBIETE the old seal marking, measured dimensions, equipment use, and operating conditions for a more reliable quotation.
How to Read an Sg Oil Seal Size Chart
The three primary dimensions
An Sg oil seal size chart usually starts with three dimensional values. The first value is the nominal shaft diameter, which corresponds to the seal’s inner diameter. The second value is the housing bore diameter, and the third value is the axial width available for the seal. For example, a chart entry shown as 35 × 52 × 7 mm generally indicates a 35 mm shaft, a 52 mm housing bore, and a 7 mm seal width.
These dimensions are nominal reference values, not permission to substitute any nearby size. A seal that is too small on the shaft can create excessive friction, while a seal that is too large may leak or fail to retain the sealing lip. The housing should also provide suitable interference and adequate support according to the seal design and manufacturer’s tolerance recommendations.
| Chart field | What it identifies | What I recommend checking |
|---|---|---|
| Inside diameter | Nominal shaft diameter | Shaft wear, runout, keyways, and surface finish |
| Outside diameter | Housing bore diameter | Bore damage, corrosion, burrs, and retention condition |
| Width | Axial installation space | Available depth, shoulder position, and adjacent components |
| Profile and material | Construction and chemical resistance | Fluid, temperature, speed, pressure, and dust exposure |
Why the Sg designation needs verification
The term Sg may refer to a particular oil seal profile or a supplier-specific designation, and catalog conventions are not always identical. Some listings use profile codes to describe a rubber-covered seal, a spring-loaded lip design, or an additional dust lip, while others use different letters for similar constructions. I therefore advise buyers to provide the complete part number, drawing, photograph, or old seal marking whenever possible.
Dimensions alone cannot confirm the sealing geometry. Two seals with the same 40 × 62 × 8 mm size may differ in lip arrangement, case construction, spring material, or elastomer. Those differences can affect installation, friction, resistance to contaminants, and service suitability.
Sg Oil Seal Materials and Profile Options
Common elastomer choices
Nitrile rubber, often abbreviated NBR, is widely used for general mineral oil and grease applications. Fluorocarbon rubber, commonly called FKM, is considered when higher temperature or stronger chemical resistance is needed, although the correct compound must still be confirmed for the specific fluid. Silicone and other specialty compounds may be suitable for selected temperature or media conditions, but they should not be chosen without application review.
As a practical selection reference, many standard NBR oil seal applications are evaluated around a working temperature range near -30°C to 100°C, while FKM is often considered for higher-temperature service that may approach 200°C, depending on compound, speed, fluid, and manufacturer limits. These are general guidance values rather than a guaranteed operating specification. I recommend using the actual TEBIETE material datasheet and application conditions before final approval.
Profile features to compare
An Sg seal may include a primary sealing lip supported by a garter spring, and some versions may include a secondary dust lip. A dust lip can help reduce the entry of dirt or moisture, but it also adds friction and may require additional installation space. A metal-cased design, rubber-covered outside diameter, or reinforced construction can each change how the seal should be installed and retained.
When I review a replacement request, I compare the original profile with the replacement drawing instead of relying on a similar-looking photograph. I also check whether the shaft rotates in one direction, operates in both directions, or remains stationary. Rotation speed is important because lip friction and heat can increase as speed rises; for example, an application operating at 3,000 rpm requires more careful review than a slow gearbox or static shaft.
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Step-by-Step Sg Oil Seal Replacement Process
Step 1: Record the original identification
Before removing the seal, record every marking on the face, outer case, or packaging. Photograph the installed position and note which side faces the oil, because the sealing lip is normally oriented toward the retained fluid. If the seal is damaged, keep the removed part for inspection rather than discarding it immediately.
Step 2: Measure the shaft, bore, and width
Clean the parts and measure the shaft with a calibrated vernier caliper or micrometer at several points. Measure the housing bore in more than one position to identify wear, ovality, or damage, and measure the available axial depth. If the original seal is compressed or distorted, do not use its damaged dimensions as the only reference.
Write the results in a consistent format, such as 45 × 65 × 8 mm, and state whether each value is measured, marked, or taken from a drawing. A difference of even 1 mm can prevent proper fit when the seal is installed in a precision housing. I also ask buyers to check whether an adapter ring, spacer, or previous repair has changed the original installation arrangement.
Step 3: Inspect the shaft and housing
A new seal cannot reliably compensate for a deeply worn shaft groove or a damaged bore. Check the lip contact area for scoring, rust, excessive polishing, or a visible wear track, and inspect the bore for burrs and sharp edges. If the shaft is worn, a repair sleeve or a revised seal position may be considered, subject to engineering approval.
Step 4: Match operating conditions
Provide the fluid type, approximate temperature, shaft speed, pressure, contamination level, and equipment environment. Also identify whether the seal is used in a pump, gearbox, motor, hydraulic assembly, agricultural machine, or another system. This information determines whether standard NBR is reasonable or whether FKM, a dust lip, a different spring material, or another profile should be reviewed.
Step 5: Confirm installation requirements
Before ordering, compare the replacement drawing with the housing depth and shaft geometry. During installation, protect the lip from keyways and splines, lubricate the sealing edge with a compatible fluid, and press the seal evenly into position. Do not hammer directly on the sealing lip or install the seal at an angle, because either action can create an immediate leak path.
Common Sg Oil Seal Replacement Mistakes
- Choosing only by outside diameter: The shaft diameter and width are equally important for fit and function.
- Ignoring the fluid: A material suitable for mineral oil may not be suitable for solvents, aggressive additives, or high-temperature fluids.
- Copying a damaged size: Wear, distortion, and hardened rubber can make the removed seal difficult to measure accurately.
- Overlooking shaft rotation: Directional or specialized lip designs may be needed for certain rotating conditions.
- Replacing without inspecting the shaft: A worn contact surface can cause repeat leakage even with a correct new seal.
How to Select a Reliable Sg Oil Seal Supplier
For a B2B purchase, I recommend evaluating more than unit price. Ask whether the supplier can provide a dimensional drawing, material information, profile confirmation, packaging details, and traceable batch identification where required. You should also confirm minimum order quantity, sample availability, production lead time, export packaging, and inspection arrangements before issuing a purchase order.
TEBIETE supports Sg oil seal sourcing by reviewing drawings, marked samples, photographs, and application data. We can help compare standard sizes with custom requirements, discuss material alternatives, and organize quotations for prototypes, maintenance batches, or repeat production. The final recommendation should remain based on the equipment manufacturer’s requirements and verified operating conditions.
Information to include in your inquiry
- Complete Sg oil seal part number or a clear photograph of the marking.
- Inside diameter, outside diameter, and width in millimeters.
- Seal profile, spring or dust-lip requirement, and installation orientation.
- Fluid, temperature, pressure, shaft speed, and contamination conditions.
- Required quantity, target delivery date, packaging needs, and destination country.
Final Recommendation
The correct Sg oil seal replacement is not determined by a size chart alone. First match the shaft diameter, housing bore, and width, then verify the Sg profile, elastomer, spring, lip arrangement, and operating conditions. Inspecting the shaft and housing is equally important because mechanical wear can be the real cause of repeated leakage.
As the next step, prepare the old seal marking or measured 3-value size, add a photo or drawing, and send the application details to TEBIETE for review. I can then help you identify a suitable standard option or clarify whether a customized seal is needed. This process gives purchasing teams and maintenance engineers a clearer basis for cost, lead-time, and replacement decisions.
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