NU215 bearing: complete specifications & equivalents
The NU215 is a ISO 15 radial bearing sized 75 x 130 x 25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | Generic ISO interchange (unbranded) |
| Bore diameter d | 75 mm |
| Outer diameter D | 130 mm |
| Width B | 25 mm |
| Seal / shield | open |
| Internal clearance | CN / C3 / C4 available |
| Tolerance class | P0 |
| Cage | steel |
| Operating temperature | -30 to +120 °C |
| Mass (geometry estimate) | 1130 g |
| Standard | ISO 15 |
| Catalog version | iso15-crb-geometry |
| Last verified | 2026-09-24 |
Source: ISO 15 boundary-dimensions standard · extracted 2026-09-24
Standard-interchange bearing: dimensions per ISO 15; CN clearance, P0 tolerance and a stamped-steel cage are catalogue defaults unless the supplier states otherwise, and mass is a geometry-derived estimate. Brand catalogue load ratings and limiting speeds for NU215 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & NU200-series range
| Bore d | 2.953 in |
|---|---|
| Outer diameter D | 5.118 in |
| Width B | 0.984 in |
| ISO bore code | 15 |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in NU200-series | 20 mm |
| Largest outer diameter in NU200-series | 180 mm |
| Width range across NU200-series | 14–34 mm |
| Bore position in NU200-series (smallest first) | 12 of 17 |
| Bore above smallest NU200-series size | 55 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NU215 model number is decoded
In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU215 are bore code 15 = 75 mm (code × 5 from 04 upward). The ISO 15 envelope is 130 mm outside diameter and 25 mm width — 2.953 × 5.118 × 0.984 in, with a 27.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.
Typical equipment & failure modes
Common applications
- machine tool gearboxes and feed drives
- conveyor and hoist gearcase shafts
- wind turbine gearbox intermediate shafts
- industrial helical and planetary gearboxes
- medium electric motor drives
Known failure patterns
- thermal seizure when an interference fit plus hot running removes all residual C3 clearance
- roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load
- edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align
- roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders
- cage fatigue and fracture after sustained over-speed with marginal lubrication
Selection pitfalls — read before you substitute
- On this 75 mm-bore NU215, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 75 mm shaft reaches operating temperature.
- The NU2 light series at 75 mm bore (130×25 mm) is the default gearbox cylindrical row; on the same bore an NU315 is larger with a much higher rating — do not replace a failed NU315 with an NU215 without re-rating L10 life.
- The 25 mm-wide NU215 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 75 mm bore and 130 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 27.5 mm section.
- For the interference inner ring of NU215, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 75 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 130 mm ring dents the raceways.
- Read the damage on a removed NU215: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 130 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.
- At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU215: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 75 mm bore band rather than extrapolating ball-bearing practice.
- Choose the ring design for the locating task: a plain NU215 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location.
Frequently asked questions
What are the dimensions of an NU215 cylindrical roller bearing?
An NU215 single-row cylindrical roller bearing per ISO 15 has a 75 mm bore, 130 mm outer diameter and 25 mm width (2.953 × 5.118 × 0.984 in), a 27.5 mm radial section and roughly 1130 g geometry-based estimated mass; catalogue masses vary with cage and E design.
How does the NU215 bore code work?
The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 15: 15 × 5 = 75 mm. The 130 mm OD and 25 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes.
What is the difference between NU, NJ, N and NUP designs?
NU (like the NU215) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical.
Can an NU215 take axial load or misalignment?
No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected.
What does the E suffix mean and which clearance should be ordered?
E (as in NU215E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 75×130×25 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty.
Reviewed & verified by the MPN Base engineering desk against source catalog iso15-crb-geometry on 2026-09-24. Read our editorial & correction policy.