7936 bearing: complete specifications & equivalents
The 7936 is a ISO 15 radial bearing sized 180 x 250 x 33 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 180 mm |
| Outer diameter D | 250 mm |
| Width B | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 145 kN |
| Basic static load rating C0 | 163 kN |
| Fatigue load limit Pu | 7.4 kN |
| Limiting speed (mechanical) | 2500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4870 g |
| Manufacturer designation | NTN 7936 |
| 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 & 7900-series range
| Bore d | 7.087 in |
|---|---|
| Outer diameter D | 9.843 in |
| Width B | 1.299 in |
| ISO bore code | 36 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 7900-series | 25 mm |
| Largest outer diameter in 7900-series | 420 mm |
| Width range across 7900-series | 9–56 mm |
| Bore position in 7900-series (smallest first) | 25 of 32 |
| Bore above smallest 7900-series size | 155 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7936 | 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 7936 model number is decoded
7936 is an NTN single-row angular contact ball bearing: extra-light, high-speed 7900 single-row family, listed in NTN Ball and Roller Bearings CAT.No.2203E at 180 x 250 x 33 mm. Decoding 7936: 79 is the single-row dimension series (extra-light, high-speed 7900 single-row family), with 36 encodes the 180 mm bore (bore code x 5); with no letter after the digits it is the standard 30 deg contact-angle execution — the 40 deg version carries a B. NTN prints 145 kN dynamic and 163 kN static for this size and a 7.4 kN fatigue load limit Pu. The 180/250/33 envelope is an ISO 15 boundary plan, so dimensional interchange with other makers holds — ratings and internal geometry do not automatically follow. Heat-mounting to 80-90 deg C is the clean route onto a 180 mm shaft; drive-fits through the balls transmit force through the contact ellipse and can brinell it.
Typical equipment & failure modes
Common applications
- heavy industrial gearbox main shafts
- large fan, blower and turbo-compressor rotors
- rolling-mill backup and drive spindles
- crusher and mill pinion shafts
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
- thermal runaway from excessive preload: the pair runs hot, grease darkens and the contact ellipse spreads until the raceways smear
- pressed-steel cage pocket wear and rivet loosening after repeated ball skid at light load and high speed
- edge loading and early spalling from housing bores that are out of round or shoulders that are too small for the ring face
- current-erosion pitting on VFD-driven motor shafts, first visible as a grey frosted band across both raceways
Selection pitfalls — read before you substitute
- At this size the shaft fit, shoulder geometry and preload procedure dominate the outcome; a 180 mm bore bearing forgives nothing in a poorly machined housing.
- The 7900 extra-light section is chosen for speed and stiffness, not for load margin — check that C0 163 kN really covers the worst static case before substituting it for a 7000.
- The C0 of 163 kN is a static rating, not a permissible running thrust — sizing continuous axial load from C0 alone is a recurring drawing-office error.
- A 7936 mounted the wrong way round still turns smoothly by hand; the failure shows up weeks later as raceway flaking on the unloaded-looking side.
- Never use a four-point or double-row bearing as a like-for-like swap for a single 7936 without re-checking axial float, heat and housing width — the kinematics differ.
- The 145/163 kN ratings and 7.4 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7936; 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 7936?
7936 is a single-row angular contact ball bearing to ISO 15: 180 mm bore, 250 mm outside diameter, 33 mm width (7.087 x 9.843 x 1.299 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 145 kN, C0 163 kN and a 7.4 kN fatigue load limit Pu; the grease limiting speed is 2,500 r/min and the oil rating 3,300 r/min; mass about 4870 g.
How is the 7936 designation structured?
79 is the single-row dimension series (extra-light, high-speed 7900 single-row family); 36 encodes the 180 mm bore (bore code x 5); with no letter after the digits it is the standard 30 deg contact-angle execution — the 40 deg version carries a B. The 250 mm OD and 33 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7936 support?
One 7936 alone takes thrust in one direction only, along its 30 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 7936?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 2,500 r/min and the oil rating 3,300 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 7936?
The 180/250/33 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 145 kN / C0 163 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.