LM503349-310 bearing: complete specifications & equivalents
The LM503349-310 is a ISO 355 radial bearing sized 46 x 75 x 18 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 46 mm |
| Outer diameter D | 75 mm |
| Width B | 18 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 62.1 kN |
| Basic static load rating C0 | 71 kN |
| Fatigue load limit Pu | 7.65 kN |
| Reference speed (thermal) | 7000 rpm |
| Limiting speed (mechanical) | 8500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 300 g |
| Manufacturer designation | SKF LM 503349/310 |
| 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 & LM503300-series range
| Bore d | 1.811 in |
|---|---|
| Outer diameter D | 2.953 in |
| Width B | 0.709 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 14.5 mm |
| Smallest bore in LM503300-series | 46 mm |
| Largest outer diameter in LM503300-series | 75 mm |
| Width range across LM503300-series | 18–18 mm |
| Bore position in LM503300-series (smallest first) | 1 of 1 |
| Bore above smallest LM503300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| LM503349-310 | 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 LM503349-310 model number is decoded
Why the cup reference matters here: in the LM503300-series tables the LM 503349 cone appears against several cup options. LM503349 is the pairing with 310, and that choice — not the cone — fixes the 75 mm OD, the raceway track position and the 18 mm assembled width.SKF LM503349 (SKF LM 503349/310) is the LM503300-series tapered roller choice for a 46 mm shaft — one row of tapered rollers on an asymmetric raceway inside the 75×18 mm envelope.Numbering ties the bearing to its inch-series envelope: LM503349 means a cone and cup matched pair in the LM503300-series series — which is why the 46×75×18 mm outline swaps dimensionally with other inch-series bearings of the same code. The SKF catalogue adds the ISO 355 dimension-series code after the bare number (e.g. ); it is the dimensional series, not a separate part number. At 7,000 r/min reference speed the 14.5 mm-section LM503349 is governed thermally by preload and lubricant flow; grease or oil selection should be made against that value, with 8,500 r/min as the mechanical ceiling. Fit selection follows the rotating ring — interference on a rotating cone — and two LM503349 units are required to take reversing thrust; keep the induced axial load inside the rated capacity when calculating the pair. Load system: the 62.1 kN basic dynamic rating C and 71 kN static rating C0 give a C0/C balance of 1.14, and dividing C by the 46 mm bore yields 1.35 kN per millimetre of journal — a density metric that compares across families; the 7.65 kN fatigue limit Pu is the floor beneath which the adjusted-life calculation drops below acceptable L10 hours for a 46 mm shaft carrying variable duty.
Typical equipment & failure modes
Common applications
- automotive and light-truck wheel hubs
- industrial gearbox shafts and reducers
- differential and pinion drives
- belt-driven fan and blower 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
- thermal preload runaway in an O-arrangement pair when inner-ring heat expands the setting
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- hard-particle indentation of the tapered raceway in unfiltered oil
Selection pitfalls — read before you substitute
- On this 46 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 LM503349 pair heats, loses setting control and smears the roller-rib contact.
- The LM503300-series inch series at 46 mm bore (75×18 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 LM503349 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.
- At the 62.1 kN rating of LM503349, preload class changes stiffness by tens of percent but also heat generation; select light preload for the 8,500 r/min speed end and heavier preload only where moment stiffness dominates.
- Open LM503349 units need application-supplied sealing and a defined EP lubricant supply; the roller-rib contact is the first to fail when the additive film breaks down.
- The 62.1/71 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 LM503349 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF LM 503349/310 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
Is LM503349 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 LM503349?
The SKF LM 503349/310 is a single-row tapered roller bearing with 46 mm bore, 75 mm outer diameter and 18 mm width (1.811 × 2.953 × 0.709 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 62.1 kN, C0 71 kN, fatigue load limit Pu 7.65 kN, reference speed 7,000 r/min, limiting speed 8,500 r/min, mass about 300 g. It is an open, separable bearing with a pressed-steel cage.
How does the LM503349 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 LM503300-series code marks the dimensional series. The metric dimensions 46×75×18 mm are the converted equivalents of the original inch boundary dimensions.
What do the cone and cup numbers in LM503349 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 (LM503300-series) groups sizes that share the same boundary-dimension plan.
Can a single LM503349 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.
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.