JS3549A-JS3510 bearing: complete specifications & equivalents
The JS3549A-JS3510 is a ANSI ABMA 19.2 radial bearing sized 35 x 70 x 24 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 35 mm |
| Outer diameter D | 70 mm |
| Width B | 24 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 69 kN |
| Basic static load rating C0 | 78 kN |
| Limiting speed (mechanical) | 5500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 420 g |
| Manufacturer designation | NTN 4T-JS3549A/JS3510 |
| 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 | 1.378 in |
|---|---|
| Outer diameter D | 2.756 in |
| Width B | 0.945 in |
| ISO bore code | — |
| 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) | 37 of 148 |
| Bore above smallest 4t-inch-series size | 22.3 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| JS3549A | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 JS3549A-JS3510 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-JS3549A/JS3510 denotes the JS prefixed family of NTN inch tapered roller bearings — cone JS3549A and cup JS3510 delivered as a matched, separable pair of 35 mm bore and 70 mm outside diameter. 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 — JS3549A sits in the JS prefixed family. The 2.0 kN of dynamic capacity per millimetre of bore summarises the 69 kN rating over the 35 mm bore — sanity-check any interchange candidate against this ratio and the 24 mm T. Cup-side note for JS3510: within the JS prefixed family tables the JS3549A cone is listed against several cup options, and it is the cup that fixes the 70 mm OD and the 24 mm assembled width — quote the full JS3549A/JS3510 pair, never the cone alone. Mount the 35 mm cone with an induction heater (max 120 °C) and press the 70 mm cup with a sleeve; driving either ring through the rollers brinells the raceways.
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
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- 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
- rolling-contact fatigue spalling after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 35 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-JS3549A/JS3510.
- The J-prefixed JS3549A code belongs to a metric-envelope inch family: its 35 mm bore is a round metric figure, yet the part still follows ABMA cone/cup numbering — do not substitute an ISO 355 metric 302/322 bearing of the same bore without checking OD, T and contact angle.
- Fit selection follows the rotating ring: a rotating cone on a 35 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
- Inch and metric bores collide on paper — 35 mm is 1.378 in, not a round metric size; a metric bearing that seems 0.1 mm off will not seat on the inch shaft.
- Quote the full JS3549A/JS3510 pair at ordering: the JS3549A cone also ships against sibling cups, and a cup from another reference changes the 24 mm assembled width and the rating.
- The 69/78 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-JS3549A/JS3510; 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-JS3549A/JS3510?
4T-JS3549A/JS3510 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 35 mm bore (1.378 in), 70 mm outside diameter and 24 mm assembled width T (2.756 × 0.945 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 69 kN, C0 78 kN, grease limiting speed 5,500 r/min, oil speed 7,300 r/min, mass about 420 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-JS3549A/JS3510 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the JS3549A cone or the JS3510 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 69/78 kN ratings change with the cup.
What is the difference between 4T-JS3549A/JS3510 and a metric ISO 355 tapered bearing?
4T-JS3549A/JS3510 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 35×70×24 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-JS3549A/JS3510 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 JS3549A/JS3510 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-JS3549A/JS3510 list two speeds, 5,500 and 7,300 r/min?
The lower figure, 5,500 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-JS3549A/JS3510 at 7,300 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.