938-932 bearing: complete specifications & equivalents
The 938-932 is a ISO 355 radial bearing sized 114.3 x 212.725 x 66.675 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 114.3 mm |
| Outer diameter D | 212.725 mm |
| Width B | 66.675 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 626 kN |
| Basic static load rating C0 | 765 kN |
| Fatigue load limit Pu | 81.5 kN |
| Reference speed (thermal) | 2600 rpm |
| Limiting speed (mechanical) | 3200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 10000 g |
| Manufacturer designation | SKF 938/932 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB |
| Last verified | 2026-09-28 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB) · extracted 2026-09-28
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch 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 & 935-series range
| Bore d | 4.5 in |
|---|---|
| Outer diameter D | 8.375 in |
| Width B | 2.625 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 49.2 mm |
| Smallest bore in 935-series | 114.3 mm |
| Largest outer diameter in 935-series | 212.725 mm |
| Width range across 935-series | 66.675–66.675 mm |
| Bore position in 935-series (smallest first) | 1 of 1 |
| Bore above smallest 935-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 938-932-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 114.3×212.725×66.675 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 938-932 | Timken | full Dimensions and internal design equivalent — standard interchange. | Same inch-series cone/cup boundary envelope (d/D/T); load ratings and speed limits are brand-specific and may differ. |
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 938-932 model number is decoded
Fit selection follows the rotating ring — interference on a rotating cone — and two 938 units are required to take reversing thrust; keep the induced axial load inside the rated capacity when calculating the pair. Journal and housing interface: the 114.3 mm bore takes a m6 shaft seat (upper deviation ~0.229 mm for this diameter range) and the 212.725 mm outside diameter pairs with an H7 housing bore tolerance band of 212.725.000/212.745 mm; the 66.675 mm width defines the shoulder depth, and the 10000 g cone-plus-cup assembly is the dead load on the shaft during thermal expansion calculations. Two catalogue entries share the 938 cone but use different cups; this one, 938, takes the 932 cup and is ground for the resulting 212.725 mm OD / 66.675 mm width envelope. Selecting a sibling cup produces a different boundary plan and a different order number, so the full designation is required at purchase.In SKF catalogue PUB BU/P1 17000, 938 appears as SKF 938/932: an open, single-row tapered roller bearing in the 935-series, supplied with a pressed-steel cage as standard.Reading the designation: 938 follows the Timken-style inch convention — the cone (inner ring with rollers) and cup (outer ring) are quoted as a pair separated by a slash, and the 935-series code identifies the dimensional series. The 114.3 mm bore, 212.725 mm OD and 66.675 mm width are the metric equivalents of the inch boundary dimensions. In SKF suffix language a bare 938 is the standard execution; B marks a larger contact angle and Q or J2 mark clearance/cage variants, all quoted separately. The 81.5 kN Pu figure feeds the adjusted-life equation at contaminated or partial-film conditions, and the 1.22 C0/C balance shows this execution is tuned to thrust-heavy combined loads rather than pure radial running.
Typical equipment & failure modes
Common applications
- large crusher and mineral-processing drives
- wind-turbine main shafts
- marine propulsion gearboxes
- wind-turbine main shafts
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
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- roller large-end smearing against the cone rib after EP lubricant film failure
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- electrical pitting on VFD-driven shafts without grounding protection
Selection pitfalls — read before you substitute
- At 114.3 mm bore the cone mass is high enough that cocking during mounting damages the cage and rib; guide the ring square, confirm seat contact around the full circumference, and re-check setting after the first thermal cycle of the paired set.
- The 935-series inch series at 114.3 mm bore (212.725×66.675 mm) follows the Timken cone/cup convention; substitutions must match both the cone and cup reference exactly — interchanging with another series or a metric 3xxxx bearing of the same bore changes OD, width and contact angle, so re-run the pair setting and shoulder-diameter checks before swapping.
- A single 938 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.
- Do not mix brands or executions inside one 938 pair — matched sets are ground for a specific setting, and pairing a SKF basic unit with a different suffix variant will not share the setting evenly.
- Catalogue reference speed and limiting speed are different limits: the 2,600 r/min reference is a thermal criterion under load, while the 3,200 r/min limiting value is the mechanical ceiling — observe both.
- The 626/765 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 938 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 938/932 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
How does 938 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 938 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
What shaft and housing fits suit 938?
For a rotating shaft under normal load, seat the cone on a m6 shaft fit; the cup is usually a loose-to-transition fit in the housing so it can creep slightly and distribute wear. Chamfer and shoulder diameters must clear the bearing rings so the 66.675 mm-wide cup seats square; the mounting setting (end play or preload) is set by the axial position of the cup relative to the cone.
Is 938 interchangeable with other brands?
Inch-series tapered roller bearings follow a long-standing industry boundary plan, so cones and cups of the same basic number are generally dimensionally interchangeable across manufacturers. However, internal geometry, cage design and load ratings differ by brand, so for paired or precision applications keep both halves of the set from one manufacturer — or re-verify ratings and setting when mixing.
What are the dimensions and catalogue data of 938?
The SKF 938/932 is a single-row tapered roller bearing with 114.3 mm bore, 212.725 mm outer diameter and 66.675 mm width (4.5 × 8.375 × 2.625 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 626 kN, C0 765 kN, fatigue load limit Pu 81.5 kN, reference speed 2,600 r/min, limiting speed 3,200 r/min, mass about 10000 g. It is an open, separable bearing with a pressed-steel cage.
How does the 938 inch-series designation work?
Inch-series tapered roller bearings use a Timken-style cone/cup convention: the number before the slash identifies the cone (inner ring with roller and cage assembly), the number after the slash identifies the cup (outer ring), and the 935-series code marks the dimensional series. The metric dimensions 114.3×212.725×66.675 mm are the converted equivalents of the original inch boundary dimensions.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB on 2026-09-28. Read our editorial & correction policy.