241-670BK30 bearing: complete specifications & equivalents
The 241-670BK30 is a ISO 15 radial bearing sized 670 x 1090 x 412 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 670 mm |
| Outer diameter D | 1090 mm |
| Width B | 412 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 14100 kN |
| Basic static load rating C0 | 28000 kN |
| Fatigue load limit Pu | 1340 kN |
| Limiting speed (mechanical) | 230 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1510000 g |
| Manufacturer designation | NTN 241/670BK30 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); 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 & 24100-series range
| Bore d | 26.378 in |
|---|---|
| Outer diameter D | 42.913 in |
| Width B | 16.22 in |
| ISO bore code | 41 |
| Radial section height (D−d)/2 | 210 mm |
| Smallest bore in 24100-series | 100 mm |
| Largest outer diameter in 24100-series | 1150 mm |
| Width range across 24100-series | 65–438 mm |
| Bore position in 24100-series (smallest first) | 31 of 32 |
| Bore above smallest 24100-series size | 570 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 241-670B | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 24100-series envelope, cage and ratings; this is the tapered-bore execution (K30, 1:30) of the cylindrical-bore 241-670B — mounting (adapter/withdrawal sleeve or tapered seat, drive-up) differs. Verify shaft arrangement. |
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 241-670BK30 model number is decoded
241/670BK30 belongs to the 24100 series of NTN spherical rollers: self-aligning, high radial capacity, moderate axial load in either direction. The leading digits are the ISO 15 dimension series (24100 series); the bore code resolves to 670 mm (two-digit code ×5, with the 00–03 exception table), and 1090 mm OD / 412 mm width follow the general plan. The bearing accepts predominantly radial load with a moderate axial share, but is not a pure thrust bearing: sustained axial-only load skids the unloaded row and damages the basic cage. Grease/oil ratio: the 230 r/min limiting value is .77 of the 300 r/min oil value; heavy 412 mm-wide cages run hot in churning grease, so quantity and groove supply both matter. Check the self-aligning movement after fitting: the housing should pivot freely around the sphered outer raceway; a pinched outer ring removes the alignment capacity the bearing was selected for.
Typical equipment & failure modes
Common applications
- cement-rotary-kiln support and trunnion rolls
- large SAG/ball-mill trunnion and pinion shafts
- heavy vibrating screens and grizzly feeders
- offshore and marine propulsion shaftlines
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- pressed EA cage fatigue under sustained vibration when minimum load is not maintained
- roller-end smearing during skidding starts under light load and high viscosity grease
- hard-particle indentation through the open arrangement in dusty mining duty
- fretting corrosion between adapter sleeve and tapered bore when the drive-up is insufficient
Selection pitfalls — read before you substitute
- At 670 mm bore 241/670BK30 is normally mounted on adapter/withdrawal sleeves with hydraulic assistance; follow the NTN drive-up angle or oil-injection procedure — manual nut tightening cannot set the multi-tonne seating correctly.
- Open spherical rollers swallow dust in mining duty; specify labyrinth or taconite seals externally, or the 230 r/min grease rating is lost to abrasive wear long before fatigue.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 412 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Never substitute 241/670BK30 by envelope alone: the 28000 kN C0 and 1340 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- Never substitute 241/670BK30 by envelope alone: the 28000 kN C0 and 1340 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- The 14100/28000 kN ratings, 1340 kN Pu and 1510000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 241/670BK30 (basic); another maker's same-envelope part revises internal geometry, so re-verify ratings and cage before substitution on vibrating or rated drives.
Frequently asked questions
What are the dimensions and catalogue data of 241/670BK30?
241/670BK30 is an NTN double-row spherical roller bearing to ISO 15: 670 mm bore, 1090 mm OD and 412 mm width (26.378 × 42.913 × 16.22 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 14100 kN, C0 28000 kN, Pu 1340 kN, grease limiting speed 230 r/min, oil 300 r/min, mass about 1510000 g. It is open, with pressed-steel cage (standard execution) and a 1:30 tapered bore.
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
K30 denotes a 1:30 tapered bore (the wide 24100 series). 241/670BK30 mounts on a matching adapter or withdrawal sleeve on a plain 670 mm shaft and is driven up to a measured radial clearance; the cylindrical-bore counterpart is 241/670B.
What do EA and EM mean on NTN spherical roller bearings?
EA is the NTN standard-capacity/high-capacity execution with a pressed sheet-steel window cage; EM is the high-capacity execution with a one-piece machined brass cage. Both use the optimised symmetric-roller design, but cage identity changes mass, speed behaviour and suitability for duties like vibrating screens, so they are separate order numbers. 241/670BK30 is the basic execution.
What do D1 and W33 mean on 241/670BK30?
241/670BK30 is listed without a D1/W33 outer-ring groove in 2203E; lubrication is supplied from the ring sides. D1 (NTN spelling) and W33 add the annular groove plus holes and are ordered as distinct suffixed executions of the same envelope.
How much misalignment and axial load can 241/670BK30 take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 24100 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 14100 kN C / 28000 kN C0 — but sustained pure axial load is not recommended because it unloads one row.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.