LM300849-LM300811 bearing: complete specifications & equivalents
The LM300849-LM300811 is a ANSI ABMA 19.2 radial bearing sized 40.988 x 67.975 x 17.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 40.988 mm |
| Outer diameter D | 67.975 mm |
| Width B | 17.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 51 kN |
| Basic static load rating C0 | 62.5 kN |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 232 g |
| Manufacturer designation | NTN 4T-LM300849/LM300811 |
| Standard | ANSI ABMA 19.2 |
| Catalog version | NTN 2203E 2026-09-25 |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN 2203E 2026-09-25) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN 2203E 2026-09-25); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & 4t-inch-series range
| Bore d | 1.614 in |
|---|---|
| Outer diameter D | 2.676 in |
| Width B | 0.689 in |
| ISO bore code | 49 |
| Radial section height (D−d)/2 | 13.5 mm |
| Smallest bore in 4t-inch-series | 12.7 mm |
| Largest outer diameter in 4t-inch-series | 260 mm |
| Width range across 4t-inch-series | 10.998–77.788 mm |
| Bore position in 4t-inch-series (smallest first) | 46 of 148 |
| Bore above smallest 4t-inch-series size | 28.288 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| LM300849-811 | SKF | 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. |
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 LM300849-LM300811 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-LM300849/LM300811 denotes the light-medium LM family of NTN inch tapered roller bearings — cone LM300849 and cup LM300811 delivered as a matched, separable pair of 40.988 mm bore and 67.975 mm outside diameter. The 4T prefix is NTN's tapered roller quality mark stamped on both parts; it is a brand mark, not a size code, so cross-references quote LM300849/LM300811 without it. The 13.5 mm radial section over the 40.988 mm bore positions the contact line of the pair; abutment shoulders and spacers are dimensioned from that geometry, not from the bore alone. Cup-side note for LM300811: within the light-medium LM family tables the LM300849 cone is listed against several cup options, and it is the cup that fixes the 67.975 mm OD and the 17.5 mm assembled width — quote the full LM300849/LM300811 pair, never the cone alone. NTN grades inch 4T bearings as open bearings without integral seals; at 40.988 mm bore the application supplies sealing and the grease fill or oil feed.
Typical equipment & failure modes
Common applications
- agricultural tractor transmission and PTO shafts
- industrial gearboxes built to inch shafting
- construction-equipment pivot and wheel positions
- mining and quarry conveyor drive pulleys
Known failure patterns
- cone-rib and roller large-end smearing when the adjusted pair runs with preload but starved lubricant film
- false brinelling on a stationary pair exposed to vibration during transport or standby
- preload loss and noise after one bearing of the adjusted pair is replaced without resetting end play
- cage damage from a mounting blow transmitted through the roller complement
- brinell marks on cone and cup raceways from impact during handling or hammer fitting
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 40.988 mm class are adjusted in pairs; verify end play against the axle or gearbox drawing and re-torque after bedding-in instead of trusting the first setting on 4T-LM300849/LM300811.
- The light-medium LM family at 40.988 mm bore (67.975×17.5 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full LM300849/LM300811 reference at purchase.
- Shaft and housing fillets must clear the ring chamfers of LM300849 and LM300811; use undercut shoulders so the rings seat on the face, not on a radius.
- An unloaded 4T-LM300849/LM300811 near 5,300 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded high-speed pairs.
- Quote the full LM300849/LM300811 pair at ordering: the LM300849 cone also ships against sibling cups, and a cup from another reference changes the 17.5 mm assembled width and the rating.
- The 51/62.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-LM300849/LM300811; internal geometry legitimately differs between inch-series makers, so re-verify ratings, adjustment and the exact cone/cup references before substituting another brand on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 4T-LM300849/LM300811?
4T-LM300849/LM300811 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 40.988 mm bore (1.614 in), 67.975 mm outside diameter and 17.5 mm assembled width T (2.676 × 0.689 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 51 kN, C0 62.5 kN, grease limiting speed 5,300 r/min, oil speed 7,000 r/min, mass about 232 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-LM300849/LM300811 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the LM300849 cone or the LM300811 cup can be replaced by an identical reference from NTN or another ABMA-dimensioned maker. Pairing the cone with a different cup reference is a different catalogue row: OD, assembled T and the 51/62.5 kN ratings change with the cup.
What is the difference between 4T-LM300849/LM300811 and a metric ISO 355 tapered bearing?
4T-LM300849/LM300811 follows the ABMA inch boundary plan with cone/cup references; ISO 355 bearings use metric dimension-series numbers (302, 322, …). Even where a metric size looks close to 40.988×67.975×17.5 mm, the envelopes and contact angles differ — the two systems are not drop-in interchangeable; check every boundary value before substituting.
What does the 4T prefix on 4T-LM300849/LM300811 mean?
4T is NTN's tapered roller bearing quality mark, stamped on cone and cup in the factory. It identifies NTN's 4T programme and is not a dimension or variant code, so interchange lists quote the bare LM300849/LM300811 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-LM300849/LM300811 list two speeds, 5,300 and 7,000 r/min?
The lower figure, 5,300 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 4T-LM300849/LM300811 at 7,000 r/min because oil removes rib-contact heat better. Real limits still depend on pair adjustment, oil flow and cooling.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN 2203E 2026-09-25 on 2026-10-01. Read our editorial & correction policy.