When it comes to machinery, rotating shafts, or high-load applications, bearings play a silent yet powerful role. Among the many types, thrust bearings are essential when you need to handle axial loads, the kind of force that pushes or pulls along the shaft’s axis rather than across it. From automotive clutches to marine equipment and heavy industrial machinery, thrust bearings make smooth, reliable motion possible.
One of the most important aspects of selecting and working with thrust bearings is understanding their size chart. These charts act like roadmaps, guiding engineers, mechanics, and DIY enthusiasts to choose the right bearing for the right job. In this post, we will dive deep into thrust bearing sizes, how to read size charts, why they matter, and provide a practical reference for commonly used dimensions.
What Is a Thrust Bearing?
A thrust bearing is a specialized type of bearing designed to support axial loads, forces acting parallel to the shaft. Unlike radial bearings that carry loads perpendicular to the shaft, thrust bearings deal with the push and pull forces generated by rotating parts.
For example:
In a car’s gearbox, thrust bearings absorb the axial load when gears shift and rotate.
In turbines or marine propellers, they ensure the shaft doesn’t push too far forward or backward.
In industrial machinery, they help maintain smooth motion even under extreme loads.
There are different designs of thrust bearings, such as ball thrust bearings, cylindrical roller thrust bearings, spherical roller thrust bearings, and tapered roller thrust bearings. Each has its own unique load-handling capacity and dimensional standards.
Why Thrust Bearing Size Charts Matter
Choosing a thrust bearing is not as simple as just grabbing one off the shelf. You need to ensure it fits precisely into your assembly and handles the expected load. Here’s why size charts are crucial:
Accuracy in Selection – A mismatch in bore or outer diameter can cause misalignment or failure.
Load Capacity Matching – Charts help match the bearing’s load rating with your application’s demands.
Interchangeability – Bearings often follow standardized dimensions (like ISO or ANSI), making it easier to replace or interchange parts across manufacturers.
Efficiency and Longevity – Using the correct size reduces wear, increases efficiency, and extends bearing life.
How to Read a Thrust Bearing Size Chart
Thrust bearing charts usually contain the following key parameters:
Bore Diameter (d) – The inner hole through which the shaft passes.
Outer Diameter (D) – The total width across the bearing.
Height/Thickness (T or H) – The overall height of the bearing assembly.
Dynamic Load Rating (C) – How much variable load the bearing can handle.
Static Load Rating (C0) – The maximum load the bearing can support without permanent deformation.
For instance, a thrust bearing may be listed as 51206 (d=30 mm, D=52 mm, H=16 mm). This means it has a 30 mm bore, 52 mm outer diameter, and 16 mm thickness.
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Thrust Bearing Size Chart (Common Dimensions)
Here’s a reference chart for standard thrust ball bearings (series 51100 and 51200). These are among the most widely used in machinery and equipment.
| Bearing No. | Bore (d) mm | Outer Diameter (D) mm | Height (H) mm | Approx. Weight (kg) |
|---|---|---|---|---|
| 51100 | 10 | 24 | 9 | 0.019 |
| 51101 | 12 | 26 | 9 | 0.021 |
| 51102 | 15 | 28 | 9 | 0.023 |
| 51103 | 17 | 30 | 9 | 0.025 |
| 51104 | 20 | 35 | 10 | 0.038 |
| 51105 | 25 | 42 | 11 | 0.060 |
| 51106 | 30 | 47 | 11 | 0.070 |
| 51107 | 35 | 52 | 12 | 0.090 |
| 51108 | 40 | 60 | 13 | 0.130 |
| 51109 | 45 | 65 | 14 | 0.150 |
| 51110 | 50 | 70 | 14 | 0.170 |
| 51204 | 20 | 40 | 14 | 0.100 |
| 51205 | 25 | 47 | 15 | 0.130 |
| 51206 | 30 | 52 | 16 | 0.160 |
| 51207 | 35 | 62 | 18 | 0.240 |
| 51208 | 40 | 68 | 19 | 0.280 |
| 51209 | 45 | 73 | 20 | 0.320 |
| 51210 | 50 | 78 | 22 | 0.370 |
These are just a few examples, actual size charts may extend across hundreds of variations depending on the series and manufacturer.
Thrust Bearing Size Chart PDF
The Thrust Bearing Size Chart provides a quick reference for engineers, mechanics, and industry professionals to select the correct bearing dimensions. With details on bore size, outer diameter, and thickness, this chart helps ensure accurate selection for smooth operation. Download this PDF to save time, reduce errors, and keep your machinery running efficiently.
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Types of Thrust Bearings and Their Size Ranges
Not all thrust bearings are created equal. Here’s a breakdown:
Ball Thrust Bearings
Handle light to moderate loads.
Sizes typically range from 10 mm bore to 200 mm bore.
Cylindrical Roller Thrust Bearings
Carry heavier axial loads.
Often used in heavy machinery and presses.
Bore sizes can range from 60 mm to over 500 mm.
Spherical Roller Thrust Bearings
Handle combined axial and radial loads.
Useful in misaligned or high-load applications like marine shafts and turbines.
Sizes: 60 mm to 710 mm bore or even larger.
Tapered Roller Thrust Bearings
High axial load capacity and stiffness.
Often used in automotive gearboxes and aerospace.
Sizes range widely depending on application.
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Practical Applications of Size Charts
Imagine you are working on a car clutch assembly. You measure the shaft and find it has a 30 mm diameter. By checking the size chart, you can quickly identify that 51206 (d=30, D=52, H=16 mm) is a suitable thrust bearing option.
In another scenario, suppose you’re repairing a marine propulsion shaft that demands high axial load capacity. Instead of a ball thrust bearing, you’d look at spherical roller thrust bearings in larger sizes like 300 mm bore, based on the chart.
Tips for Choosing the Right Thrust Bearing
Measure Accurately – Use a vernier caliper or micrometer for shaft and housing.
Check Load Ratings – Match with both static and dynamic loads.
Consider Speed – High-speed applications may need specialized bearings.
Environment – Dust, water, or high temperatures may require sealed or lubricated variants.
Future Availability – Stick to standardized sizes for easy replacements.
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Advantages of Using Standard Size Charts
Saves time when selecting bearings.
Reduces risk of mismatched parts.
Improves machine life with correct fitment.
Provides interchangeability across brands like SKF, NSK, Timken, and FAG.
Final Thoughts
Thrust bearings might look small compared to the massive machines they support, but their role is undeniably critical. A properly chosen thrust bearing ensures smooth, reliable performance and prevents costly breakdowns. That’s why the thrust bearing size chart is more than just numbers, it’s a practical tool for engineers, mechanics, and anyone working with rotating equipment.
Whether you are dealing with a tiny 10 mm bore bearing for a small gearbox or a 700 mm spherical thrust bearing in a turbine, the size chart is your go-to guide. Use it wisely, measure accurately, and always select the right bearing for the job.
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FAQs
What is a thrust bearing used for?
A thrust bearing is designed to handle axial loads — forces that push or pull along the shaft. Unlike radial bearings, it supports motion in the same direction as the shaft’s axis. They are widely used in automotive clutches, marine propellers, gearboxes, and heavy industrial machines where smooth, reliable forward or backward movement is critical.
How do I choose the right thrust bearing size?
To choose the correct thrust bearing, measure the shaft diameter (bore), the housing (outer diameter), and the required load capacity. Then match these with a thrust bearing size chart. Selecting the wrong size can cause misalignment, excessive wear, or even failure. Always check both static and dynamic load ratings for your specific application.
What are the types of thrust bearings?
The main types of thrust bearings are ball thrust bearings, cylindrical roller thrust bearings, spherical roller thrust bearings, and tapered roller thrust bearings. Each type suits different load and speed conditions. For example, ball thrust bearings handle lighter loads, while spherical roller thrust bearings are ideal for heavy-duty applications with misalignment or combined axial and radial forces.
What is the difference between thrust and radial bearings?
Thrust bearings support axial loads (forces along the shaft), while radial bearings handle radial loads (forces perpendicular to the shaft). For example, a radial bearing might support a spinning wheel, whereas a thrust bearing in a gearbox absorbs the push when gears engage. In many machines, both types are used together to balance different load directions.
Where are thrust ball bearings commonly used?
Thrust ball bearings are commonly used in car gearboxes, machine tools, and light-duty industrial machinery. Their compact design allows them to support moderate axial loads at relatively high speeds. They are not ideal for heavy vibration or extreme loads but are perfect for everyday equipment where smooth rotation and precise alignment are essential for reliable operation.
What is the load capacity of thrust bearings?
The load capacity of thrust bearings varies depending on type and size. Ball thrust bearings typically handle lighter loads up to a few kilonewtons, while roller thrust bearings can manage extremely high loads, often exceeding hundreds of kilonewtons. Always check the dynamic and static load ratings in manufacturer catalogs to match your specific application’s requirements.
Can thrust bearings handle radial loads?
Most thrust bearings are designed for axial loads only and are not suitable for significant radial loads. However, some designs, such as spherical roller thrust bearings, can accommodate limited radial forces while primarily carrying axial loads. If your application involves combined forces, it’s important to select a thrust bearing specifically rated for both axial and radial support.