LM806649-LM806610 bearing: complete specifications & equivalents
The LM806649-LM806610 is a ANSI ABMA 19.2 radial bearing sized 53.975 x 88.9 x 19.05 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 53.975 mm |
| Outer diameter D | 88.9 mm |
| Width B | 19.05 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 67.5 kN |
| Basic static load rating C0 | 82.5 kN |
| Limiting speed (mechanical) | 4000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 437 g |
| Manufacturer designation | NTN 4T-LM806649/LM806610 |
| 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 | 2.125 in |
|---|---|
| Outer diameter D | 3.5 in |
| Width B | 0.75 in |
| ISO bore code | 49 |
| Radial section height (D−d)/2 | 17.5 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) | 67 of 148 |
| Bore above smallest 4t-inch-series size | 41.275000000000006 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| LM806649-610 | 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 LM806649-LM806610 model number is decoded
For an inch shaft of 53.975 mm carrying combined radial and thrust load, NTN lists 4T-LM806649/LM806610, a single-row 4T tapered roller set of 67.5 kN C and 82.5 kN C0 inside the 88.9 mm OD cup. Letter prefixes inherited from the inch convention mark the load family: LM reads as light-medium, HM as heavy-medium, LL as extra-light, J-prefixed codes as metric-envelope families — LM806649 sits in the light-medium LM family. The 17.5 mm radial section over the 53.975 mm bore positions the contact line of the pair; abutment shoulders and spacers are dimensioned from that geometry, not from the bore alone. Housing fitment sequence for 4T-LM806649/LM806610: press the LM806610 cup square into the 88.9 mm seat first, then bring the LM806649 cone (on its 53.975 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. After bedding-in, re-check the end play of the adjusted 4T-LM806649/LM806610 pair — initial seating of the ring faces relaxes the setting slightly.
Typical equipment & failure modes
Common applications
- machine-tool headstocks on inch spindles
- pump and blower drive shafts with combined load
- truck and trailer axle hubs on inch-dimensioned axles
- agricultural tractor transmission and PTO shafts
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 fatigue when the pair runs continuously near the grease limiting speed without oil cooling
- edge loading when shaft deflection exceeds the few arc-minutes an adjusted pair tolerates
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 53.975 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-LM806649/LM806610.
- The light-medium LM family at 53.975 mm bore (88.9×19.05 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full LM806649/LM806610 reference at purchase.
- ABMA makes the 53.975×88.9 mm envelope interchangeable, not the ratings: NTN prints 67.5/82.5 kN for this execution and another make of the same number can differ in roller complement.
- Never drive the 88.9 mm cup home through the rollers: fitting force goes through the ring faces only, or brinell marks release as noise within the first running hours.
- Shaft and housing fillets must clear the ring chamfers of LM806649 and LM806610; use undercut shoulders so the rings seat on the face, not on a radius.
- The 67.5/82.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-LM806649/LM806610; 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-LM806649/LM806610?
4T-LM806649/LM806610 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 53.975 mm bore (2.125 in), 88.9 mm outside diameter and 19.05 mm assembled width T (3.5 × 0.75 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 67.5 kN, C0 82.5 kN, grease limiting speed 4,000 r/min, oil speed 5,300 r/min, mass about 437 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-LM806649/LM806610 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the LM806649 cone or the LM806610 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 67.5/82.5 kN ratings change with the cup.
What is the difference between 4T-LM806649/LM806610 and a metric ISO 355 tapered bearing?
4T-LM806649/LM806610 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 53.975×88.9×19.05 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-LM806649/LM806610 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 LM806649/LM806610 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-LM806649/LM806610 list two speeds, 4,000 and 5,300 r/min?
The lower figure, 4,000 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-LM806649/LM806610 at 5,300 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.