15123-15243 bearing: complete specifications & equivalents
The 15123-15243 is a ISO 355 radial bearing sized 31.75 x 61.912 x 18.161 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 31.75 mm |
| Outer diameter D | 61.912 mm |
| Width B | 18.161 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 59.5 kN |
| Basic static load rating C0 | 57 kN |
| Fatigue load limit Pu | 6.2 kN |
| Reference speed (thermal) | 9000 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 240 g |
| Manufacturer designation | SKF 15123/15243 |
| 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 & 15000-series range
| Bore d | 1.25 in |
|---|---|
| Outer diameter D | 2.437 in |
| Width B | 0.715 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 15.1 mm |
| Smallest bore in 15000-series | 25.4 mm |
| Largest outer diameter in 15000-series | 62 mm |
| Width range across 15000-series | 18.161–19.05 mm |
| Bore position in 15000-series (smallest first) | 2 of 2 |
| Bore above smallest 15000-series size | 6.350000000000001 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 15123-15245-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 31.75×61.912×18.161 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 15123-15243 | 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 15123-15243 model number is decoded
For a 31.75 mm shaft carrying combined load, SKF lists 15123 under catalogue execution SKF 15123/15243: one open single-row tapered roller bearing in the inch 15000-series.In SKF inch-series tables 15123 sits at 31.75 mm bore (1.25 in) with a 61.912 mm cup OD and 18.161 mm total width — dimensions that trace back to the original Timken boundary plan for the 15000-series family. In SKF suffix language a bare 15123 is the standard execution; B marks a larger contact angle and Q or J2 mark clearance/cage variants, all quoted separately. Selection arithmetic: the C0/C ratio is about 0.96 (static 57 kN against dynamic 59.5 kN), typical of a tapered roller sized for axial capacity, and the 6.2 kN fatigue load limit Pu is the equivalent-load floor used in the life calculation. Mounting practice for 15123: the rotating cone takes the interference fit (k5 on a 31.75 mm shaft), the cup slides for axial location, and reversing-thrust duty demands a paired O/X set rather than one bearing. Journal and housing interface: the 31.75 mm bore takes a k5 shaft seat (upper deviation ~0.064 mm for this diameter range) and the 61.912 mm outside diameter pairs with an H7 housing bore tolerance band of 61.912.000/61.932 mm; the 18.161 mm width defines the shoulder depth, and the 240 g cone-plus-cup assembly is the dead load on the shaft during thermal expansion calculations. Within the 15000-series tables, 15123 appears in several rows because SKF lists multiple cup options for the same cone. 15123 is the 15243 variant, with 61.912 mm OD and 18.161 mm width; neighbouring rows on the same cone differ only in the cup but are separate orderable bearings.
Typical equipment & failure modes
Common applications
- automotive and light-truck wheel hubs
- industrial gearbox shafts and reducers
- differential and pinion drives
- automotive and light-truck wheel hubs
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
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- On this 31.75 mm bore, interference and temperature rise consume clearance inside a preloaded pair; calculate the residual clearance after mounting and at operating temperature — an over-tight 15123 pair heats, loses setting control and smears the roller-rib contact.
- The 15000-series inch series at 31.75 mm bore (61.912×18.161 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.
- Do not mix brands or executions inside one 15123 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.
- A single 15123 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.
- Shaft and housing fillets must clear the bearing chamfer so the 18.161 mm-wide cup seats square; use an undercut or withdrawal groove rather than an oversized radius that locks on the ring face.
- The 59.5/57 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 15123 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 15123/15243 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of 15123?
The SKF 15123/15243 is a single-row tapered roller bearing with 31.75 mm bore, 61.912 mm outer diameter and 18.161 mm width (1.25 × 2.437 × 0.715 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 59.5 kN, C0 57 kN, fatigue load limit Pu 6.2 kN, reference speed 9,000 r/min, limiting speed 11,000 r/min, mass about 240 g. It is an open, separable bearing with a pressed-steel cage.
How does the 15123 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 15000-series code marks the dimensional series. The metric dimensions 31.75×61.912×18.161 mm are the converted equivalents of the original inch boundary dimensions.
What do the cone and cup numbers in 15123 mean?
The cone number (before the slash) identifies the inner ring, rollers and cage; the cup number (after the slash) identifies the outer ring. Both are quoted together because a single-row tapered roller bearing is a matched separable pair — the cone and cup are ground to work together and are not interchangeable with arbitrary other parts. The series prefix (15000-series) groups sizes that share the same boundary-dimension plan.
Can a single 15123 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 15123 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 15123 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. 8.2 inch single-row TRB on 2026-09-28. Read our editorial & correction policy.