33115 bearing: complete specifications & equivalents
The 33115 is a ISO 355 radial bearing sized 75 x 125 x 37 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 75 mm |
| Outer diameter D | 125 mm |
| Width B | 37 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 216 kN |
| Basic static load rating C0 | 265 kN |
| Fatigue load limit Pu | 30 kN |
| Reference speed (thermal) | 4000 rpm |
| Limiting speed (mechanical) | 5000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1800 g |
| Manufacturer designation | SKF 33115 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & 33100-series range
| Bore d | 2.953 in |
|---|---|
| Outer diameter D | 4.921 in |
| Width B | 1.457 in |
| ISO bore code | 15 |
| Radial section height (D−d)/2 | 25 mm |
| Smallest bore in 33100-series | 40 mm |
| Largest outer diameter in 33100-series | 180 mm |
| Width range across 33100-series | 26–56 mm |
| Bore position in 33100-series (smallest first) | 8 of 12 |
| Bore above smallest 33100-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33115 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 355 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 33115 model number is decoded
33115 is a single-row tapered roller bearing in the ISO 33100 dimension series: a separable cone-and-cup design for combined radial and one-direction axial load, listed by SKF in SKF catalogue PUB BU/P1 17000.On the SKF nameplate, 33115 follows the ISO 355 convention: 3 for the tapered-roller type, 31 for the light wide section, final digits 15 for the 75 mm bore. In SKF suffix language a bare 33115 is the standard execution; B marks a larger contact angle and Q or J2 mark clearance/cage variants, all quoted separately. The 25.0 mm radial section height ((125−75)/2) and 1800 g catalogue mass frame a 75 mm bore bearing rated at 216 kN C — roughly 2.88 kN of dynamic capacity per millimetre of bore before application factors. Fit selection follows the rotating ring — interference on a rotating cone — and two 33115 units are required to take reversing thrust; keep the induced axial load inside the rated capacity when calculating the pair.
Typical equipment & failure modes
Common applications
- rolling-mill auxiliary drives
- crane sheave and hoist gearboxes
- paper-machine and printing rolls
- construction machinery drives
Known failure patterns
- cup or cone misalignment when the separable rings are not seated square during mounting
- loose cup rotation in the housing when the specified press fit is not achieved
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- Mount the 75 mm bore 33115 by induction heating of the cone (max 120 °C — the pressed-steel cage sets the ceiling, not the steel); driving it home through the cup or rollers brinells the tapered raceway.
- The 331 series at 75 mm bore (125×37 mm) pairs a small OD with a wide section — a compact way to add capacity where radial space is tight; abutment and spacer widths differ from the 330/302 families, so it is not a drop-in swap.
- A single 33115 cannot locate the shaft axially in both directions; mounting it singly on a reversing-thrust shaft leaves one direction uncontrolled — always use an O or X matched pair for bidirectional location.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of 33115 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- The pressed-steel cage is rated for standard industrial service; sustained running above the limiting speed or with degraded lubricant wears the cage pockets — inspect the cage at every relubrication interval.
- The 216/265 kN ratings are SKF catalogue 17000 values for the basic execution; SKF can revise internal geometry without changing the order number, so keep the catalogue version (PUB BU/P1 17000/1 EN, 2018) with the specification and re-verify for critical drives.
- SKF lists several executions of 33115 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 33115 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 33115?
The SKF 33115 is a single-row tapered roller bearing with 75 mm bore, 125 mm outer diameter and 37 mm width (2.953 × 4.921 × 1.457 in) per ISO 355. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 216 kN, C0 265 kN, fatigue load limit Pu 30 kN, reference speed 4,000 r/min, limiting speed 5,000 r/min, mass about 1800 g. It is an open, separable bearing with a pressed-steel cage.
How does the 33115 bore code work?
The last two digits of 33115 are bore code 15, so 15 × 5 = 75 mm bore. The 125 mm OD and 37 mm width come from the ISO 355 dimension-series plan, shared with other tapered bearings of the same code.
What do the 33115 series and basic execution designations mean?
The leading 3 marks a single-row tapered roller bearing; the second digit 31 is the ISO 355 series (light wide section). The SKF catalogue lists the ISO 355 dimension-series code after the bare number. A steeper-contact-angle variant (B suffix) is a different order number and is not interchangeable with the basic execution.
Can a single 33115 take axial load in both directions?
No — one single-row tapered roller bearing reacts thrust in one direction only, and under radial load its contact angle induces an axial force. Use two bearings as a matched pair: O (back-to-back) for a rigid, moment-resisting arrangement, X (face-to-face) where thermal expansion must be tolerated, or tandem where one-direction thrust is shared.
How does 33115 compare with a ball bearing of the same bore?
A tapered roller bearing has line contact and a steep contact angle: much higher combined axial-plus-radial capacity and shock resistance than a ball bearing of the same bore, at the cost of speed, one-direction thrust, mandatory pairing for reversing loads and a minimum axial load requirement. A ball bearing cannot be dropped into a combined-load 33115 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.1 metric single-row TRB on 2026-09-26. Read our editorial & correction policy.