30203 bearing
17 × 40 mm · dynamic rating 23.4 kN · static rating 18.6 kN. Dimensions, load ratings, designation meaning, life estimates and equivalent parts.
30203 specification
| Designation | 30203 |
| Type | Tapered roller bearing |
| Series | 302 standard-angle |
| Bore diameter d | 17 mm |
| Outside diameter D | 40 mm |
| Basic dynamic load rating C | 23.4 kN (23,400 N) |
| Basic static load rating C0 | 18.6 kN (18,600 N) |
| Ratio C0/C | 0.79 |
| Speed guide, grease lubrication | 18,000 rpm |
| Life exponent p | 10/3 (roller bearing) |
Values come from the Rotec AI bearing catalogue and are indicative. Confirm against the manufacturer's current catalogue before ordering. Not every dimension (such as width) is listed here.
What the designation 30203 means
| Code | Meaning |
|---|---|
| 302 | Tapered roller bearing, standard contact angle series |
| 03 | bore code "03" = 17 mm (one of the four fixed small-bore codes, not the ×5 rule) |
Basic rating life of the 30203
Basic rating life is L10 = (C / P)p million revolutions, where P is the equivalent dynamic load and p = 10/3 (roller bearing). For a 30203 with C = 23.4 kN, the table shows what that gives at different load levels. It is the ISO 281 basic life only: it does not include lubrication, contamination, misalignment or reliability modifiers.
| C / P | P as share of C | L10 (million rev) | L10 at 1,500 rpm | L10 at 3,000 rpm |
|---|---|---|---|---|
| 3 | 33.3% | 39 | 430 | 220 |
| 5 | 20.0% | 214 | 2,400 | 1,200 |
| 8 | 12.5% | 1,024 | 11,400 | 5,700 |
| 12 | 8.3% | 3,956 | 44,000 | 22,000 |
For example, a C / P of 5 means the equivalent load is 4.68 kN on this bearing. Use the Load Calculator to work out P for your actual radial and axial loads.
Equivalents of the 30203
Brand-by-brand equivalents for this exact designation are not shown here. The Cross-Reference tool accepts SKF, FAG, NSK, NTN, Timken, Koyo and NRB designations, and shows what is catalogued.
Where the 30203 is used
Tapered roller bearings are chosen for: Combined radial and axial load; stiffness. Typical equipment: Wheel hubs, gearboxes, rail wheelsets, construction/agri equipment. Usually adjusted/preloaded; paired arrangements common.
Other sizes in the same series
The 30203 belongs to the “302 standard-angle” series. The next size down, the 30202, has a bore of 15 mm and a dynamic rating of 18.5 kN. The next size up, the 30204, has a bore of 20 mm and a rating of 34.1 kN (+46%).
Common problems on bearings like the 30203
Most field failures trace back to lubrication, contamination, fits and alignment rather than the bearing itself. These guides explain how to recognise and prevent them:
Questions about the 30203
What are the dimensions of a 30203 bearing?
The 30203 has a bore of 17 mm and an outside diameter of 40 mm. It is a tapered roller bearing. Series: 302 standard-angle.
What is the load rating of a 30203 bearing?
In the Rotec AI catalogue the 30203 has a basic dynamic load rating C of 23.4 kN and a basic static load rating C0 of 18.6 kN. Always confirm against the manufacturer's current catalogue.
What is the equivalent of a 30203 bearing?
Use the Cross-Reference tool in Rotec AI to check brand equivalents for the 30203.