61917-NSK bearing: complete specifications & equivalents
The 61917-NSK is a ISO 15 radial bearing sized 85 x 120 x 18 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NSK |
| Bore diameter d | 85 mm |
| Outer diameter D | 120 mm |
| Width B | 18 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 35 kN |
| Basic static load rating C0 | 29.6 kN |
| Operating temperature | -40 to +150 °C |
| Mass | 550 g |
| Manufacturer designation | NSK 6917 |
| Standard | ISO 15 |
| Catalog version | NSK Rolling Bearings E1103 Part C |
| Last verified | 2026-09-24 |
Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24
Dimensions in inches & 61900-series range
| Bore d | 3.346 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 0.709 in |
| ISO bore code | 17 |
| Radial section height (D−d)/2 | 17.5 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) | 25 of 63 |
| Bore above smallest 61900-series size | 82 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61917-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | Same 85×120×18 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting. |
| 61917-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 85×120×18 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting. |
| 61917-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 85×120×18 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting. |
| 61917-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 85×120×18 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting. |
| 61917 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 85×120×18 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 61917-NSK model number is decoded
61917 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 17 by five gives the 85 mm bore; the 120 mm outside diameter and 18 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 85 mm shaft under normal load, catalogue practice seats it on a k5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. In the NSK catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (steel shields), VV (non-contact rubber seals) and DDU (contact rubber seals).
Typical equipment & failure modes
Common applications
- packaging machinery
- space-constrained gearboxes
- clutch and transmission assemblies
- robotics and automation joints
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- brinelling from static overload or hammering during mounting
- false brinelling from vibration while the shaft is stationary
Selection pitfalls — read before you substitute
- Mount this 85 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 619xx thin section at 85 mm bore (17.5 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: 61917-NSK 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 61917 units.
- Measure the shaft, do not trust the drawing: a 85 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 61917-NSK.
- Suffixes stack in a defined order — clearance follows the seal code, e.g. 61917-NSK-C3. No clearance suffix means normal CN clearance.
- The open 61917 has no integral sealing; in the NSK E1103 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), VV (non-contact rubber seals) and DDU (contact rubber seals). NSK does not offer a low-torque contact seal equivalent to NTN's LLH in this catalogue — for high-speed sealed duty specify the VV non-contact seal and an external housing labyrinth.
- At 85 mm bore 61917 is in NSK's medium industrial range; the pressed-steel cage is standard, but large-section 63xx sizes at this bore can be ordered with a machined brass cage (suffix M) for heavy-shock or very-low-speed duty — confirm cage material with the NSK channel if the application sees impact loads.
- NSK rates 61917 at 35 kN dynamic (C) and 29.6 kN static (C0); this upper-medium rating covers conveyor and gearbox drives, but at these loads the pressed-steel cage can be the limiting factor under shock — consider the machined brass cage (suffix M) for impact duty.
- At 550 g, 61917 requires a soft-jaw vise or arbor press for mounting — never hammer it onto the shaft, and support the opposite ring to avoid brinelling the raceways.
- The 85×120×18 mm envelope of 61917 gives a D/d ratio of 1.41 and 17.5 mm radial section height — this NSK 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 35/29.6 kN load ratings, mass 550 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6917 on the 85×120×18 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61917 in a rated drive. NSK does not tabulate reference or limiting speeds in the E1103 Part C dimension tables used for this page — consult NSK's separate speed-rating tables before high-speed service.
- NSK's VV non-contact seal keeps frictional torque close to the open 61917; in motor duty where heat build-up matters, VV is the usual compromise between debris protection and speed capability.
- NSK does not recommend washing new shielded or sealed bearings; the rust-preventive film on open units is compatible with standard lithium greases and needs no removal unless the application demands a special fill.
Frequently asked questions
What are the dimensions of a 61917-NSK bearing?
A 61917-NSK deep-groove ball bearing has a 85 mm bore, 120 mm outer diameter and 18 mm width (3.346 × 4.724 × 0.709 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How does the 61900 compare with other series at the same 85 mm bore?
619 is a thin section one step above 618: 120×18 mm with a 17.5 mm radial section at 85 mm bore; a 6217 on the same bore is substantially larger and more heavily rated.
Are 61917 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 61917 uses the same ISO 15 envelope (85×120×18 mm). Load ratings, limiting speeds, clearance, precision class and sealing design can differ, so verify those in the supplier catalogue when substituting.
What is the NSK order number for an open 61917?
NSK lists the open 61917 under the bare designation 6917; protected versions use suffixes ZZ (steel shields), VV (non-contact rubber seals) and DDU (contact rubber seals) on the same 85 mm bore envelope.
What is the difference between NSK VV and DDU seals?
VV is a non-contact rubber seal: low torque, speed close to the open bearing, dust-tight but not liquid-tight. DDU is a contact rubber seal: far better exclusion of moisture and fine dust, at the cost of a lower speed ceiling and higher running torque. 6917 keeps the same ISO 15 envelope either way.
Reviewed & verified by the MPN Base engineering desk against source catalog NSK Rolling Bearings E1103 Part C on 2026-09-24. Read our editorial & correction policy.