61960-NTN bearing: complete specifications & equivalents
The 61960-NTN is a ISO 15 radial bearing sized 300 x 420 x 56 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 300 mm |
| Outer diameter D | 420 mm |
| Width B | 56 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 305 kN |
| Basic static load rating C0 | 375 kN |
| Fatigue load limit Pu | 13.7 kN |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 23500 g |
| Manufacturer designation | 6960 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203-3/E (2024) |
| Last verified | 2026-09-25 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)); 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 & 61900-series range
| Bore d | 11.811 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 2.205 in |
| ISO bore code | 60 |
| Radial section height (D−d)/2 | 60 mm |
| Smallest bore in 61900-series | 3 mm |
| Largest outer diameter in 61900-series | 1120 mm |
| Width range across 61900-series | 3–118 mm |
| Bore position in 61900-series (smallest first) | 44 of 63 |
| Bore above smallest 61900-series size | 297 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61960 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 300×420×56 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting. |
| 61960-MA | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 300×420×56 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting. |
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 61960-NTN model number is decoded
61960 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the thin 619xx section (diameter series 9 of ISO 15), multiplying bore code 60 by five gives the 300 mm bore; the 420 mm outside diameter and 56 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 300 mm shaft under normal load, catalogue practice seats it on a m6 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. In the NTN catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal).
Typical equipment & failure modes
Common applications
- space-constrained gearboxes
- clutch and transmission assemblies
- robotics and automation joints
- lay shafts and idler shafts
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- cage damage from operation beyond the limiting speed
- electrical pitting in VFD-driven motors without grounding protection
Selection pitfalls — read before you substitute
- Large bores like the 300 mm of 61960-NTN demand clean, burr-free seats; one raised burr under a ring this size cocks the bearing and concentrates load at the raceway edge, cutting life drastically.
- The 619xx thin section at 300 mm bore (60.0 mm section height) cannot shrug off the misalignment a standard section tolerates; keep the housing bores round and aligned, or edge contact will spall the raceways early.
- Storage matters for open bearings: 61960-NTN leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
- Open bearings tolerate the highest speeds in the 61900-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61960 units.
- Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 56 mm-wide ring of 61960-NTN drags the lip and overheats it.
- Never mix components between two 61960-NTN units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
- The open 61960 has no integral sealing; in the NTN 2203 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), LLB/LLF (non-contact rubber seals), LLU (contact rubber seals) and LLH (a low-torque contact seal with higher speed capability than LLU). A JR or JRX suffix (printed for some thin-section sizes) denotes a pressed-steel cage, not a seal.
- The 300 mm bore places 61960 in NTN's extra-large range; the pressed-steel cage is not recommended at this diameter and NTN supplies a machined brass cage (suffix M) as the standard offering. Speed ratings are low, housing alignment is critical, and oil lubrication with a defined relubrication interval is mandatory — consult NTN engineering before sizing.
- NTN lists the grease limiting speed at 1400 r/min for 61960; this is a large-section size where the pressed-steel cage is speed-limited — NTN recommends the machined brass cage (suffix M) and oil lubrication for any continuous operation above this figure.
- NTN rates 61960 at 305 kN dynamic (C) and 375 kN static (C0), 13.7 kN fatigue load limit Cu; this is an upper heavy-load rating where the pressed-steel cage is not recommended — NTN supplies a machined brass cage (suffix M) and the static C0 must be verified against any shock or lifting loads the bearing sees during mounting.
- At 23500 g (23.5 kg), 61960 is a very heavy bearing where handling and mounting method directly affect service life; NTN requires induction heating of the inner ring (max 120 °C), a mechanical puller for removal, and a defined lifting procedure to avoid damaging the machined brass cage.
- The 300×420×56 mm envelope of 61960 gives a D/d ratio of 1.40 and 60.0 mm radial section height — this thin section saves space but is sensitive to misalignment and shock; confirm the housing stays round within IT7 and the shaft does not deflect past the raceway contact angle under load.
- The 305/375 kN load ratings, 13.7 kN fatigue load limit Cu NTN lists the grease limiting speed at 1400 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 23500 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6960 on the 300×420×56 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61960 in a rated drive.
- Two NTN bearings of the same designation from different production lots can carry minor internal-geometry revisions; for paired or preloaded arrangements on one shaft, order a single lot through the NTN distributor.
- NTN date-codes its packaging; rotate stock first-in-first-out, because the grease inside sealed units ages on the shelf — after three to five years of storage, check the grease condition before putting the bearing into service.
Frequently asked questions
What are the dimensions of a 61960-NTN bearing?
A 61960-NTN deep-groove ball bearing has a 300 mm bore, 420 mm outer diameter and 56 mm width (11.811 × 16.535 × 2.205 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How should 61960-NTN be mounted?
Apply the mounting force to the ring being fitted: on a 300 mm shaft seat the press load must pass through the inner-ring face only. Induction heating of the inner ring (max 120 °C) is the clean method at this size. Never strike the outer ring, the cage or the seals.
What lubrication does 61960-NTN need?
The open 61960-NTN is lubricated by the application; a NLGI 2 lithium-soap grease filled to roughly 25–35% of the free volume is the common choice, with a defined relubrication interval.
What is the NTN order number for an open 61960?
NTN lists the open 61960 under the bare designation 6960; protected versions use suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal) on the same 300 mm bore envelope.
Is 6960 a current NTN production size?
The NTN 2203-series catalogue lists it as a standard size; availability of specific seal executions (ZZ, LLB/LLF, LLH, LLU) varies by region and stock — confirm with an NTN distributor before specifying spares.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203-3/E (2024) on 2026-09-25. Read our editorial & correction policy.