Designation Systems / Cylindrical Roller Bearings
Cylindrical Roller Bearing Designation System
A cylindrical roller bearing designation is a basic designation (type letter, dimension series and bore code) plus optional suffixes that describe the internal design, cage, clearance and special features. Single row designs (N, NU, NJ, NUP, NF) guide the rollers between ribs on one ring, so the bearing carries high radial loads and — depending on the type letter — locates the shaft axially in one or both directions. Double row designs (NN, NNU, and the full complement NNCF / NNCL / NNC and sealed NNF / SL families) add a second roller row for still higher radial capacity. Each manufacturer publishes its own designation system; the tables below put the five brands that catalogue this type side by side.
Anatomy of a Designation
NU 2205 ECP
Example shown in SKF style
NU 2205Basic designation — NU design (non-locating), 22 dimension series, bore code 05 = 25 mm
ECType & internal designOptimised internal design with more and/or larger rollers and modified roller end / flange contact
PCageGlass fibre reinforced PA66 cage, roller centred
Bore code (last two digits of the basic designation)
00 = 10 mm bore01 = 12 mm bore02 = 15 mm bore03 = 17 mm bore04 and up = bore (mm) = code × 5/nnn = explicit bore in millimetres (e.g. NU 10/500 = 500 mm bore)
SKF
Type letters & series
| N | Two integral ribs on the outer ring, inner ring without ribs — non-locating |
| NU | Two integral ribs on the inner ring, outer ring without ribs — non-locating (radial loads only) |
| NJ | NU plus one rib on the outer ring — semi-locating, axial load in one direction |
| NUP | NJ plus a loose rib on the outer ring — locating, axial load in both directions |
| NUH / NCF / NJG | Single row high-capacity and full complement designs |
| NNC / NNCL / NNCF / NNF | Double row designs — full complement (NNC / NNCL / NNCF, modified design CV) and sealed (NNF, -2LS) |
| 3194.. | Sealed double row design, the earlier designation for the NNF width series |
Prefixes
| L | Separate inner or outer ring of a separable bearing |
| R | Inner or outer ring with roller and cage assembly of a separable bearing |
| HJ | Angle ring (L-section ring for the N / NU types) |
Type & internal design
| A | Deviating or modified internal design |
| CV | Modified internal design, full complement roller set |
| EC | Optimised internal design incorporating more and/or larger rollers and with modified roller end / flange contact |
| K | Tapered bore, taper 1:12 |
Seals & outer-ring features
| N | Snap ring groove in the outer ring |
| NR | Snap ring groove in the outer ring, with associated snap ring |
| N1 / N2 | One / two locating slots (notches) in one outer ring side face |
| -2LS | Contact seal (PUR) on both sides |
| ADB / B / DA | Modified internal design and seal (NNF 50 / 3194 series, sealed designs) |
Cage
| FR | Pin-type steel cage, pierced rollers |
| J / JA / JB | Stamped / sheet steel cage, roller or ring centred |
| P / PA | Glass fibre reinforced PA66 cage, roller or outer ring centred |
| PH / PHA | Glass fibre reinforced PEEK cage, roller or outer ring centred |
| M / MA / MB / MH / ML / MP / MR | Machined brass cage (various centring and window types) |
| V / VH | Full complement of rollers (no cage); VH is self-retaining |
Clearance, accuracy & stabilization
| CN / C2 / C3 / C4 / C5 | Radial internal clearance: Normal, smaller than Normal, greater than Normal, greater than C3 / C4 |
| H / L / M | Reduced clearance range: upper / lower / middle half of the actual clearance range |
Other features
| S1 / S2 | Bearing rings heat stabilized for operating temperatures ≤ 200 / 250 °C |
NSK
Type letters & series
| NU | Non-locating — two integral ribs on the inner ring |
| N | Non-locating — two integral ribs on the outer ring |
| NJ | Semi-locating — one rib on the outer ring |
| NUP | Locating — NJ plus a loose rib on the outer ring |
| NF | Semi-locating — one rib on the inner ring |
| NN / NNU | Double row designs (NN: two inner ring ribs; NNU: two outer ring ribs) |
Type & internal design
| E | High load capacity design (increased number / size of rollers) |
Cage
| W | Pressed steel cage |
| M | Machined brass cage |
| T / T7 | Synthetic resin cage (catalog prints the cage option per size) |
Clearance, accuracy & stabilization
| C2 / CN / C3 / C4 | Radial internal clearance smaller than / equal to / greater than / much greater than Normal |
| P6 / P5 / P4 / P2 | Accuracy to ISO class 6 / 5 / 4 / 2 |
Schaeffler (FAG)
Type letters & series
| N2xx / N3xx | Non-locating bearings with cage (two ribs on the inner ring) |
| NU2xx / NU22xx / NU23xx / NU3xx / NU4xx / NU10xx / NU19xx | Non-locating bearings with cage, light to heavy and extra-light series |
| NJ2xx / NJ22xx / NJ23xx / NJ3xx / NJ4xx | Semi-locating / locating bearings with cage (one outer ring rib) |
| NUP2xx / NUP22xx / NUP23xx / NUP3xx | Locating bearings with a loose outer ring rib |
| LSL19xx | Single row bearings with disc cage |
| SL18xx / SL19xx | Single row full complement bearings (no cage) |
| SL1850xx | Double row full complement bearing, semi-locating (no cage) |
| SL0148xx / SL0149xx | Double row full complement bearing, locating (no cage) |
| SL0248xx / SL0249xx | Double row full complement bearing, non-locating (no cage) |
| SL0450xx / SL04ddd | Double row full complement bearing with annular slots, sealed (-D-PP), locating |
Type & internal design
| E | Increased capacity design (standard) |
| EX | Increased capacity design, design modified in accordance with standard |
| TB | Bearing with increased axial load carrying capacity (toroidal crowned design) |
Cage
| TVP2 | Solid window cage made from glass fibre reinforced polyamide PA66 |
| M1 / M1A / M1B | Solid brass cage, two-piece, roller- or rib-guided |
| MPAX / MPBX | Solid brass cage, single-piece, rib-guided on outer / inner ring |
| JP3 | Sheet steel window cage, single-piece, roller-guided |
Clearance, accuracy & stabilization
| C3 / C4 / C5 | Radial internal clearance larger than normal / larger than C3 / larger than C4 |
Other features
| XL | X-life bearing |
| J30P | Black oxide coated (Durotect B) |
NTN
Type letters & series
| NU10 / NU2 / NU22 / NU3 / NU23 / NU4 | Dimension series: extra-light, light, wide light, medium, wide medium, heavy |
| NJ / NUP / N / NF | Type letters for semi-locating, locating and the alternative non-locating designs |
| NN30 / NNU49 | Double row designs (NN30 and NNU49 series) |
Type & internal design
| E | Increased load capacity design |
| EA | ULTAGE increased load capacity design |
| K | Tapered bore, taper 1:12 (double row designs) |
Clearance, accuracy & stabilization
| CN / C3 | Normal / greater than normal radial internal clearance |
Timken
Type letters & series
| N / NJ / NU / NUP | Metric type codes: non-locating, semi-locating and locating designs |
| 10xx / 19xx / 20xx / 22xx / 23xx / 29xx / 30xx / 31xx / 39xx | Metric dimension series |
| NCF..V | Single row full complement design (no cage) |
| 200RU / RN / RJ / RF / RT | Inch standard series; the two-letter code selects the rib configuration of the same boundary size |
Type & internal design
| E | Metric series high-capacity design (part of the printed suffix combination) |
Other features
| ETP / EMA / EMB / EJ / MA | Printed design / cage suffix combination; one size can be supplied in several variants with the same boundary dimensions |
Good to Know
- The type letter sets the axial locating behaviour: N and NU are non-locating (radial load only), NJ and NF are semi-locating (axial load in one direction), NUP is locating (axial load in both directions). NU is the most common design.
- The same bearing is written differently by each brand: SKF NU 2205 ECP, Schaeffler (FAG) NU2205-E-XL-TVP2, NSK NU2205E, NTN NU2205EA, Timken NU2205ETP.
- The dimension series is part of the basic designation: 10 = extra-light, 2 = light, 22 = wide light, 3 = medium, 23 = wide medium, 4 = heavy. A trailing "E" (Schaeffler, NSK, NTN) or "EA" (NTN ULTAGE) marks an increased-capacity design of the same boundary dimensions.
- An explicit bore is written after a slash for the large sizes (NU 10/500 = 500 mm bore).
- Full complement single row bearings have no cage; SKF writes this with V / VH (modified design CV), Timken with a trailing V on the NCF designation, and Schaeffler (FAG) sells its full complement single row line under its own SL / LSL / ZSL designations rather than an ISO type code.
- Cages differ by brand and size: pressed steel, glass fibre reinforced PA66 (P / TVP2), PEEK (PH) and machined brass (M / M1 / ...) are all used, and Schaeffler (FAG) and SKF print the cage in the suffix while NSK and NTN keep it out of the designation.
- Double row cylindrical roller bearings (NN, NNU, NNC, NNCL, NNCF, NNF, and the Schaeffler SL18xx / SL01xx / SL02xx / SL04xx families) are a separate structure carried by their own catalogue tables; their type letters and series are listed above and they share the same bore-code and suffix rules. Most double row designs are full complement or sealed (no cage); the sealed designs publish only a limiting speed under grease lubrication.
- Tapered-bore versions of the double row designs have their own suffix and their own page here: NSK prints a trailing KR (NN3005KR), NTN a trailing K (NN3005K), both for a 1:12 taper. Schaeffler (FAG) uses K in the same sense, but its SL18xx / SL01xx / SL02xx / SL04xx double row tables and the SKF and Timken double row tables list no tapered-bore size, so no such designation exists for those brands.
- Availability of a suffix varies by size — always confirm the exact designation in the manufacturer catalog you are ordering from.
Disclaimer: Data on this page is compiled from publicly available online sources for reference only, and not every model appears in a manufacturer's published catalog. Values may differ between sources and editions — always verify against the manufacturer's current documentation before design or purchase.Full disclaimer →
