7201B bearing: complete specifications & equivalents
The 7201B is a ISO 15 radial bearing sized 12 x 32 x 10 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 12 mm |
| Outer diameter D | 32 mm |
| Width B | 10 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 7.75 kN |
| Basic static load rating C0 | 3.65 kN |
| Fatigue load limit Pu | 0.29 kN |
| Limiting speed (mechanical) | 21000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 36 g |
| Manufacturer designation | NTN 7201B |
| 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 & 7200-series range
| Bore d | 0.472 in |
|---|---|
| Outer diameter D | 1.26 in |
| Width B | 0.394 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 10 mm |
| Smallest bore in 7200-series | 10 mm |
| Largest outer diameter in 7200-series | 540 mm |
| Width range across 7200-series | 9–85 mm |
| Bore position in 7200-series (smallest first) | 2 of 36 |
| Bore above smallest 7200-series size | 2 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7201B | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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 7201B model number is decoded
From the medium-duty 7200 single-row family, 7201B measures 12 mm across the bore, 32 mm over the outer ring and 10 mm across the faces. The designation breaks down as 72 is the single-row dimension series (medium-duty 7200 single-row family); 01 encodes the 12 mm bore (bore code x 5), and the trailing B marks the 40 deg contact-angle execution (the no-letter standard bearing works at 30 deg). On speed, the grease limiting speed is 21,000 r/min and the oil rating 28,000 r/min. The 12/32/10 envelope is an ISO 15 boundary plan, so dimensional interchange with other makers holds — ratings and internal geometry do not automatically follow. Shaft and housing shoulders must clear the ring corners yet support enough face — the catalogue abutment diameters for the 12 mm bore give the working limits.
Typical equipment & failure modes
Common applications
- bicycle and motorcycle wheel and steering positions
- small gearbox pinion shafts with helical gears
- precision instrument and encoder support shafts
- small machine-tool spindle and live-centre positions
Known failure patterns
- false brinelling on the raceway contact ellipses when a preloaded spindle sits vibrating at standstill — visible as evenly spaced flute-like wear at ball pitch
- loss of preload after housing-fret or shaft creep, leaving the pair loose — ball skidding, cage rattle and a falling natural frequency follow
- resin-cage cracking on the 7900-series sizes after hot, dry running or solvent attack on the polymer
- lubricant starvation scoring at the ball/raceway contact when grease volume or relubrication interval is guessed instead of calculated
- lubricant starvation scoring at the ball/raceway contact when grease volume or relubrication interval is guessed instead of calculated
Selection pitfalls — read before you substitute
- At 12 mm bore the rings are thin-sectioned: press force must go through the ring being fitted, never through the balls, or the first damage is already in the raceway before the machine runs.
- The 40 deg B-execution raises axial capacity but lowers the speed ceiling — do not copy the standard-bearing speed and preload settings onto it.
- The 21,000 r/min speed figure assumes the catalogue lubrication state and a correctly set pair; real limits drop fast with excess grease fill or heavy preload.
- Catalogue mass and ratings belong to the open execution; shields, seals and resin cages change both the speed ceiling and the thermal behaviour of the same basic size.
- The C0 of 3.65 kN is a static rating, not a permissible running thrust — sizing continuous axial load from C0 alone is a recurring drawing-office error.
- The 7.75/3.65 kN ratings and 0.29 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7201B; internal geometry legitimately differs between manufacturers, so re-verify ratings, contact angle and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 7201B?
7201B is a single-row angular contact ball bearing to ISO 15: 12 mm bore, 32 mm outside diameter, 10 mm width (0.472 x 1.26 x 0.394 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 7.75 kN, C0 3.65 kN and a 0.29 kN fatigue load limit Pu; the grease limiting speed is 21,000 r/min and the oil rating 28,000 r/min; mass about 36 g.
How is the 7201B designation structured?
72 is the single-row dimension series (medium-duty 7200 single-row family); 01 encodes the 12 mm bore (bore code x 5), and the trailing B marks the 40 deg contact-angle execution (the no-letter standard bearing works at 30 deg). The 32 mm OD and 10 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7201B support?
One 7201B alone takes thrust in one direction only, along its 40 deg contact angle; reversing thrust calls for a second bearing or a factory-matched DB/DF/DT pair (the catalogue right-hand columns list the paired ratings). Radial load is always carried as a combined load through the angled contact.
What lubrication speeds does NTN print for 7201B?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 21,000 r/min and the oil rating 28,000 r/min. These are catalogue ceilings for a correctly mounted bearing with the stated lubricant; preload, fill quantity, ambient heat and paired arrangements all move the real limit.
What should be checked before substituting another make for 7201B?
The 12/32/10 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 7.75 kN / C0 3.65 kN, the speed figures, contact angle and suffix meaning against the donor catalogue before swapping on a rated drive.
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.