61972 bearing: complete specifications & equivalents

The 61972 is a ISO 15 radial bearing sized 360 x 480 x 56 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.

Bearing dimension schematic Front view shows outer diameter D and bore d; side section shows width B. D = 480 mm d = 360 B = 56 mm side section front view
Principal dimensions: bore d 360 mm, outer diameter D 480 mm, width B 56 mm. Schematic, not to scale.

Specification table

ParameterValue
Brand NTN
Bore diameter d 360 mm
Outer diameter D 480 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 330 kN
Basic static load rating C0 455 kN
Fatigue load limit Pu 14.8 kN
Limiting speed (mechanical) 1100 rpm
Operating temperature -40 to +120 °C
Mass 27500 g
Manufacturer designation 6972
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 d14.173 in
Outer diameter D18.898 in
Width B2.205 in
ISO bore code72
Radial section height (D−d)/260 mm
Smallest bore in 61900-series3 mm
Largest outer diameter in 61900-series1120 mm
Width range across 61900-series3–118 mm
Bore position in 61900-series (smallest first)47 of 63
Bore above smallest 61900-series size357 mm

Cross references & equivalents

Equivalent modelBrandMatch levelNote
61972-MA SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 360×480×56 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 61972 model number is decoded

In the 61900-series (diameter series 9 of ISO 15) the last two digits encode the bore: 61972 carries bore code 72 = 360 mm. Outside diameter 480 mm and width 56 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 360 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. 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
  • edge loading from shaft deflection or housing misalignment
  • rolling-contact fatigue spalling after the rated L10 life is exceeded

Selection pitfalls — read before you substitute

  • Large bores like the 360 mm of 61972 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 360 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: 61972 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 61972 units.
  • Never mix components between two 61972 units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
  • Deep-groove ball bearings tolerate only minutes of misalignment; if the 480 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 61972.
  • The open 61972 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 360 mm bore places 61972 in NTN's maximum-size range at the lower end; this is a heavy-engineering bearing where centrifugal force and cage inertia dominate the design envelope. NTN supplies a machined brass cage (suffix M) and expects oil lubrication; do not use catalogue grease speed figures for this size without an NTN engineering review.
  • NTN lists the grease limiting speed at 1100 r/min for 61972; 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 61972 at 330 kN dynamic (C) and 455 kN static (C0), 14.8 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 27500 g (27.5 kg), 61972 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 360×480×56 mm envelope of 61972 gives a D/d ratio of 1.33 and only 60.0 mm radial section height — this is an ultra-thin section where shaft deflection and housing ovality directly load the ball-raceway contact; verify shaft stiffness (target deflection under 0.05 mm) before specifying it over a 62-series.
  • The 330/455 kN load ratings, 14.8 kN fatigue load limit Cu NTN lists the grease limiting speed at 1100 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 27500 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6972 on the 360×480×56 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61972 in a rated drive.
  • Factory-fill grease in NTN sealed units is a general-duty lithium-soap grease; food-grade, low-temperature and high-temperature fills are request options at order time, because LLU/LLB units are not meant to be opened and re-greased in the field.
  • 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 61972 bearing?

A 61972 deep-groove ball bearing has a 360 mm bore, 480 mm outer diameter and 56 mm width (14.173 × 18.898 × 2.205 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.

What internal clearance does 61972 have?

Unless a clearance suffix says otherwise, 61972 is manufactured to normal (CN) radial internal clearance. Tight fits and hot shafts consume clearance in service — for those conditions order the C3 execution of 61972 and verify the residual clearance after mounting.

How should 61972 be mounted?

Apply the mounting force to the ring being fitted: on a 360 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 is the NTN order number for an open 61972?

NTN lists the open 61972 under the bare designation 6972; protected versions use suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal) on the same 360 mm bore envelope.

What cage does NTN fit in 6972?

Standard is a pressed-steel cage with no suffix; larger sizes or shock-loaded duty can be supplied with a machined brass cage (suffix M) as a separate order number. The catalogue figures quoted here are for the pressed-steel execution.

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.