Sep. 30, 2026
To select a replacement grease seal, you normally need three primary dimensions: shaft diameter, housing bore diameter, and seal width. These dimensions are commonly written as inside diameter × outside diameter × width, such as 35 × 52 × 7 mm. I recommend measuring the shaft and housing directly whenever possible, then confirming the seal profile, lip material, spring arrangement, temperature range, and lubricant compatibility before placing an order.
This guide explains how to read a grease seal size chart, measure a removed seal, handle damaged or missing dimensions, and prepare accurate information for a supplier such as TEBIETE. The examples below are for identification and comparison, not a substitute for a manufacturer’s drawing or application-specific recommendation.
A grease seal chart normally lists nominal dimensions in a fixed order. For many rotary shaft seals, the order is inside diameter (ID) × outside diameter (OD) × width. The ID fits around the shaft, the OD fits into the housing, and the width describes how far the seal occupies the axial space in the bore.
| Dimension | Common abbreviation | What it matches | How to measure |
|---|---|---|---|
| Inside diameter | ID | Rotating or stationary shaft diameter | Measure the shaft where the sealing lip runs |
| Outside diameter | OD | Housing or bore diameter | Measure the seal housing bore after cleaning |
| Width | W | Available axial installation space | Measure the old seal or the housing depth |
For example, a chart entry marked 40 × 62 × 8 mm generally indicates a 40 mm shaft diameter, a 62 mm housing bore, and an 8 mm seal width. However, some catalogs use a different order or separate metric and inch sections, so I always confirm the chart legend before interpreting a part number. A similar-looking dimension can still be unsuitable if the seal has a different profile or installation depth.
The following chart shows common dimensional formats rather than a universal interchange list. These example sizes help explain how measurements are organized and should not be treated as proof that any specific seal fits a particular machine. Final selection should be based on the equipment drawing, original part information, or verified measurements.
| Example ID | Example OD | Example width | Typical chart notation | Verification required |
|---|---|---|---|---|
| 25 mm | 40 mm | 7 mm | 25 × 40 × 7 mm | Profile, material, and shaft condition |
| 35 mm | 52 mm | 7 mm | 35 × 52 × 7 mm | Housing fit and lip orientation |
| 40 mm | 62 mm | 8 mm | 40 × 62 × 8 mm | Speed, temperature, and lubricant |
| 50 mm | 72 mm | 10 mm | 50 × 72 × 10 mm | Installation depth and sealing environment |
A grease seal with the correct nominal dimensions may still fail if the application requires a dust lip, a metal-cased design, a high-temperature elastomer, or a special pressure arrangement. I therefore treat a size chart as the first screening tool rather than the complete specification. For procurement, the dimensional drawing and technical requirements should control the final decision.
Before measuring, identify the equipment, shaft location, lubricant, and reason for replacement. Remove grease, rust, dirt, and seal fragments from the shaft and housing because contamination can affect readings and hide wear. If the shaft has a visible groove at the former lip contact area, record it because a new seal with the same size may not correct a damaged running surface.
Use a calibrated vernier caliper or micrometer to measure the shaft at the area contacted by the sealing lip. Take readings at more than one position around the circumference and along the contact path to check for taper, ovality, or a wear groove. Record the smallest and largest readings rather than writing down only one measurement.
Do not measure a rusted or damaged edge and assume it represents the original shaft size. If the shaft is rotating, the seal lip must match the actual shaft surface and speed conditions, not merely the nominal diameter shown on an old seal. When the measured value differs noticeably from the expected standard size, pause the selection process and investigate shaft wear or an incorrect replacement part.
Clean the housing bore and inspect it for scoring, deformation, corrosion, or remnants of adhesive. Measure the bore in at least two directions, preferably at multiple depths, because a distorted housing can produce different readings. The outside diameter of the replacement seal must be matched to the actual bore and the required retention method.
For a metal-cased grease seal, the housing condition is especially important because the case and outer covering influence the fit. A rubber-covered outer diameter may accommodate some surface conditions differently from a bare metal case, but I do not recommend using this difference to compensate for an incorrect dimension. The supplier should review the bore condition and seal construction together.
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Measure the removed seal’s total width if it remains intact, then measure the housing depth with a depth gauge or suitable caliper. The replacement width should not interfere with an internal shoulder, retaining ring, bearing, or adjacent component. A seal that is too wide may not seat fully, while one that is too narrow may not provide the intended retention or protection.
Record whether the seal is installed flush with the housing, recessed, or positioned at a specified depth. Installation depth can affect lip contact, dust protection, and clearance from moving components. A simple cross-sectional sketch or photograph with the key dimensions often helps a supplier confirm the correct design.
Size alone does not describe the full grease seal. Note whether the seal has one sealing lip, a secondary dust lip, an exposed spring, an internal spring, a metal case, a rubber-covered outside diameter, or a special flanged design. Also record the direction of the sealing lip and any visible marking on the original component.
Material selection should reflect the lubricant and working environment. NBR is widely used in general oil and grease sealing applications, while FKM may be considered where higher temperature or specific chemical resistance is required; suitability depends on the exact formulation and operating conditions. PTFE-based designs may be selected for specialized chemical, friction, or temperature requirements, but they may also require different installation practices.
| Factor | Information to provide | Why it matters |
|---|---|---|
| Speed | Rotational speed in rpm | Influences heat generation and lip design |
| Temperature | Minimum and maximum operating temperature in °C | Helps screen elastomer and lubricant compatibility |
| Lubricant | Grease type, base oil, and additives where known | Some compounds can affect elastomer performance |
| Environment | Dust, water, mud, chemicals, or pressure | Determines lip, dust-exclusion, and case requirements |
For example, a seal running at 1,800 rpm in a clean gearbox may require a different lip consideration from one operating at low speed in abrasive dust and water. Temperature should be recorded in °C, and the actual maximum should include heat from the machine, lubricant, and surrounding equipment. If pressure is present, confirm that the selected grease seal is designed for that condition rather than assuming a standard seal can handle it.
I also recommend avoiding forced substitutions based on a nearly similar size. A small difference in OD can change housing retention, while a small difference in ID can alter lip interference and friction. If the original size is unavailable, the supplier should review the fit, material, and application before approving an alternative.
At TEBIETE, I help B2B buyers organize the information needed for standard replacement seals and application-specific designs. You can provide the ID, OD, width, seal profile, material preference, operating speed, temperature, lubricant, quantity, and delivery requirements. If the old seal is damaged, a dimensioned drawing, clear photographs, and housing details can help us assess the replacement more accurately.
For repeat purchasing, I recommend confirming a controlled specification that includes dimensional tolerances, material, lip configuration, packaging, marking, and inspection requirements. For custom or non-standard grease seals, quotation, minimum order quantity, tooling considerations, and lead time depend on the design complexity and requested volume. I will state these commercial details clearly after reviewing the technical requirements rather than offering an unsupported fixed promise.
The correct replacement grease seal is selected by matching the shaft diameter, housing bore diameter, and width, then confirming the profile and operating conditions. Measure the shaft and housing directly, use consistent units, and inspect for wear before relying on the old seal’s markings. A chart entry such as 35 × 52 × 7 mm is useful only when its dimension order and application requirements have been verified.
Your next step is to prepare a measurement sheet with ID, OD, width, shaft condition, speed in rpm, temperature in °C, lubricant, environment, quantity, and any drawing or packaging requirements. Send that information to TEBIETE for a technical review and quotation. I can then help you determine whether a standard grease seal is suitable or whether a customized material, profile, or dimensional solution is more appropriate.
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