241-500BK30 bearing: complete specifications & equivalents
The 241-500BK30 is a ISO 15 radial bearing sized 500 x 830 x 325 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 500 mm |
| Outer diameter D | 830 mm |
| Width B | 325 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 9000 kN |
| Basic static load rating C0 | 16700 kN |
| Fatigue load limit Pu | 870 kN |
| Limiting speed (mechanical) | 330 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 705000 g |
| Manufacturer designation | NTN 241/500BK30 |
| 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 | 19.685 in |
|---|---|
| Outer diameter D | 32.677 in |
| Width B | 12.795 in |
| ISO bore code | 41 |
| Radial section height (D−d)/2 | 165 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) | 26 of 32 |
| Bore above smallest 24100-series size | 400 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 241-500B | 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 241-500B — 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 241-500BK30 model number is decoded
For heavy radial load with misalignment on a 500 mm shaft, NTN supplies 241/500BK30: sphered outer raceway, two roller rows, pressed-steel cage (standard execution), oil speed 430 r/min. The leading digits are the ISO 15 dimension series (24100 series); the bore code resolves to 500 mm (two-digit code ×5, with the 00–03 exception table), and 830 mm OD / 325 mm width follow the general plan. The plain outer ring (no D1/W33 groove) makes relubrication part of the design: fresh grease reaches the rolling elements through the outer-ring feature rather than relying solely on end-side packing. The 165.0 mm section height hosts the spherical roller geometry; shaft and housing fillet radii must clear the chamfer table so the 325 mm-wide ring seats fully on both sides. On vibrating-duty shafts verify the radial clearance class and cage choice at order time; the open 241/500BK30 leaves sealing and the C3/C4 clearance decision to the application drawing.
Typical equipment & failure modes
Common applications
- large SAG/ball-mill trunnion and pinion shafts
- heavy vibrating screens and grizzly feeders
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
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
- sliding wear and heat when relubrication intervals ignore the groove (D1/W33) supply path
- false brinelling on stopped machines exposed to screen or crusher vibration
- asymmetric wear on the two roller rows from sustained angular misalignment beyond the self-aligning range
Selection pitfalls — read before you substitute
- At 500 mm bore 241/500BK30 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 330 r/min grease rating is lost to abrasive wear long before fatigue.
- Oil relubrication toward 430 r/min needs drain and level design; flooding the 325 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- Self-aligning does not mean unlimited misalignment: beyond the catalogue angle the outer ring's spherical travel is exhausted and the 9000 kN rating no longer applies.
- K and K30 are different tapers — K is 1:12 and K30 is 1:30 on the wide series; an adapter sleeve for one will not mount the other 500 mm bearing, and drive-up procedures differ.
- The 9000/16700 kN ratings, 870 kN Pu and 705000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 241/500BK30 (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 241/500BK30?
241/500BK30 is an NTN double-row spherical roller bearing to ISO 15: 500 mm bore, 830 mm OD and 325 mm width (19.685 × 32.677 × 12.795 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 9000 kN, C0 16700 kN, Pu 870 kN, grease limiting speed 330 r/min, oil 430 r/min, mass about 705000 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). 241/500BK30 mounts on a matching adapter or withdrawal sleeve on a plain 500 mm shaft and is driven up to a measured radial clearance; the cylindrical-bore counterpart is 241/500B.
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. 241/500BK30 is the basic execution.
What do D1 and W33 mean on 241/500BK30?
241/500BK30 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 241/500BK30 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 — 9000 kN C / 16700 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.