LM12749-711 bearing: complete specifications & equivalents
The LM12749-711 is a ISO 355 radial bearing sized 22 x 45.974 x 15.494 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 22 mm |
| Outer diameter D | 45.974 mm |
| Width B | 15.494 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 33.9 kN |
| Basic static load rating C0 | 31 kN |
| Fatigue load limit Pu | 3.2 kN |
| Reference speed (thermal) | 12000 rpm |
| Limiting speed (mechanical) | 15000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 120 g |
| Manufacturer designation | SKF LM 12749/711 |
| 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 & LM12700-series range
| Bore d | 0.866 in |
|---|---|
| Outer diameter D | 1.81 in |
| Width B | 0.61 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 12 mm |
| Smallest bore in LM12700-series | 22 mm |
| Largest outer diameter in LM12700-series | 45.974 mm |
| Width range across LM12700-series | 15.494–15.494 mm |
| Bore position in LM12700-series (smallest first) | 1 of 1 |
| Bore above smallest LM12700-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| LM12749-LM12711 | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| LM12749-711 | 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 LM12749-711 model number is decoded
In SKF suffix language a bare LM12749 is the standard execution; B marks a larger contact angle and Q or J2 mark clearance/cage variants, all quoted separately. The 3.2 kN Pu figure feeds the adjusted-life equation at contaminated or partial-film conditions, and the 0.91 C0/C balance shows this execution is tuned to thrust-heavy combined loads rather than pure radial running. A single LM12749 locates the shaft in one axial direction only; mount it against a second bearing in O (back-to-back) or X (face-to-face) arrangement, and set the running clearance by the mounting procedure — not by feel. Load system: the 33.9 kN basic dynamic rating C and 31 kN static rating C0 give a C0/C balance of 0.91, and dividing C by the 22 mm bore yields 1.54 kN per millimetre of journal — a density metric that compares across families; the 3.2 kN fatigue limit Pu is the floor beneath which the adjusted-life calculation drops below acceptable L10 hours for a 22 mm shaft carrying variable duty. Cone versus cup responsibility in LM12749: the LM 12749 cone carries the 22 mm bore, rollers and pressed-steel cage; the 711 cup carries the 45.974 mm OD raceway, the roller-seating rib and the outer press-fit surface. The two references are not interchangeable halves.The SKF LM 12749/711 is a 22×45.974×15.494 mm single-row tapered roller bearing — an inch-series entry with an asymmetric raceway cut for thrust capacity and separable mounting.Digit by digit, LM12749 reads as cone reference / cup reference in the LM12700-series inch series; the 22 mm bore, 45.974 mm OD and 15.494 mm width are the metric equivalents of the original inch boundary values.
Typical equipment & failure modes
Common applications
- steering knuckles and small differentials
- agricultural implement hubs
- small conveyor drive pulleys
- small automotive wheel hubs and trailer axles
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
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- rib-roller contact scoring from loss of the EP additive film
Selection pitfalls — read before you substitute
- At a 22 mm bore the thin cone and cup are easily distorted by an over-tight shaft nut; check seat runout (target Ra ≤ 0.8 µm) and torque the locknut progressively — a pinched LM12749 shows up as gearbox vibration long before it fails.
- The LM12700-series inch series at 22 mm bore (45.974×15.494 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 LM12749 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 LM12749 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.
- The LM12749 shares its ISO 355 envelope with other tapered bearings of the same code but is not a drop-in replacement for a ball bearing: it cannot run effectively under pure radial load without a minimum axial load, and a deep-groove bearing cannot replace its combined-load duty.
- The 33.9/31 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 LM12749 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF LM 12749/711 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What do the cone and cup numbers in LM12749 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 (LM12700-series) groups sizes that share the same boundary-dimension plan.
Can a single LM12749 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 LM12749 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 LM12749 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
What shaft and housing fits suit LM12749?
For a rotating shaft under normal load, seat the cone on a k5 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 15.494 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 LM12749 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.
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.