Designation Systems / Tapered Roller Bearings
Tapered Roller Bearing Designation System
A tapered roller bearing designation is a basic designation plus optional suffixes. For the metric ISO sizes the basic designation is a number: 3 (tapered roller bearing type code) + two digits of dimension series (02, 03, 13, 20, 22, 23, 29, 30, 31, 32) + the two-digit bore code. The rollers run between conical raceways on the inner ring (cone) and outer ring (cup), so the bearing carries high combined radial and axial loads and — because the rings are separable — the two halves are often ordered as a matched pair, and one cone can be combined with several cups. Matched pairs and double row designs carry their own designations: SKF writes a matched pair with a /DF (face-to-face), /DB (back-to-back) or /DTC.. (tandem) suffix after the basic designation, and it marks its double row TDO and TDI designs with assembly designations such as BT2B 332767 A; NSK writes its double row sizes as KBE (for example HR40KBE42+L). Bearing Go catalogues those as bearings in their own right — a matched pair keeps the single row row-type and records the arrangement, a double row design is Double Row — rather than treating them as variants of a single row base. Inch sizes are therefore identified by a cone/cup pair (for example LM11749/LM11710) and the metric T dimension-plan codes (T2ED020, T4CB075) come from the ANSI/ABMA system. Each manufacturer publishes its own designation system; the sections below put the five brands that catalogue this type side by side.
Anatomy of a Designation
32206 B
Example shown in SKF style
32206Basic designation — 3 (tapered roller bearing), 22 dimension series (wide light), bore code 06 = 30 mm
BInternal designModified internal design — increased contact angle (steeper cup, higher axial capacity)
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/nn = explicit bore code after a slash (320/22 = 22 → 110 mm bore)
SKF
Series & designations
| 302xx / 303xx / 313xx | Single row metric, dimension series 2 / 3 / 13 (light, medium, steep-angle) |
| 320xx / 322xx / 323xx | Single row metric, wide series 20 / 22 / 23 |
| 329xx / 330xx / 331xx / 332xx | Single row metric, extra-wide series |
| 320/22, 302/28 | Bore code written after a slash (the digits give the bore in millimetres divided by five) |
| LM 11749/710 | Inch sizes (8.2) — SKF prints the cone/cup pair, abbreviating the cup to its trailing digits (cone LM11749 + cup LM11710) |
| /DF, /DB, /DTC.. | Matched pair suffix after the basic designation — two single row bearings supplied as one pre-adjusted pair: face-to-face (8.4), back-to-back (8.5), tandem (8.6) |
| BT2B 332767 A | Double row TDO / TDI design with its own assembly designation (sections 8.7 / 8.8) |
Internal design
| B | Modified internal design — increased contact angle (steeper cup) |
| X | External dimensions to ISO (used on the 32xxx / 33xxx series) |
Outer-ring features
| R | Outer ring with a flange (section 8.3 table) |
| BR | Increased contact angle (B) combined with a flanged outer ring (R) |
Clearance & accuracy
| CL7C | Tighter than normal running tolerance (printed against the size in the catalogue) |
NSK
Series & designations
| HR302.. / HR303.. / HR322.. / HR323.. | Metric single row series with the HR high-capacity prefix |
| HR32926J, HR32004XJ | Trailing letter = internal design; X = external dimensions to ISO |
| HR302/22, HR320/22XJ | Bore code written after a slash |
| LM11749/LM11710 | Inch sizes printed as a cone/cup pair (two columns, "INNER RING" / "OUTER RING"); one cone can be matched with several cups |
| HR40KBE42+L | Double row metric size — KBE design with the +L suffix as printed; B2 is the overall width (pp. 124-128) |
Prefixes
| HR | High load capacity design |
Internal design
| C | Medium-angle design (suffix printed after the bore number, e.g. HR30205C) |
| D | Steep-angle design (e.g. 30303D) |
| X | External dimensions to ISO |
Cage
| J | Pressed steel cage (printed directly after the bore number, e.g. HR30302J) |
Schaeffler (FAG)
Series & designations
| 302xx … 332xx | Single row to DIN/ISO (metric): dimension series 02, 03, 13, 20, 22, 23, 29, 30, 31, 32 |
| 329/22, 320/22 | Bore code after a slash (329/22 → 22 → 110 mm bore) |
| T2ED020, T4CB075, T7FC045 | The "T" dimension-plan codes for the ANSI/ABMA inch sizes (ISO 10317 / ISO 355 plans) |
| KLM11749-LM11710 | Inch ANSI/ABMA cone/cup pair; the pair is joined with a hyphen after the K prefix, a trailing -XL drops the X-life suffix |
Internal design
| -A | Modified internal design |
| -B / -BA | Modified internal design (steeper contact angle) |
| -X | Modified design with ISO boundary dimensions |
Other features
| -XL | X-life bearing (premium design, longer service life) |
NTN
Series & designations
| 4T-30203 … 4T-303xx | Metric series; the 4T- prefix marks the NTN interchangeable tapered roller bearing |
| 30216U, 30232UUTG | Design suffixes of the larger sizes (printed verbatim in the catalogue) |
| 4T-LM11749/LM11710 | Inch sizes written as a 4T- cone/cup pair |
Prefixes
| 4T- | Prefix marking the NTN interchangeable tapered roller bearing series |
Other features
| U / UTG | Printed design suffix of the size (kept verbatim in the designation) |
Timken
Series & designations
| cone / cup | A single-row bearing is two orderable parts: the cone (inner ring, with the rollers) and the cup (outer ring), e.g. LM11749 / LM11710 |
| TS | Single-row standard design (inch and metric ISO) |
| TSF | Single-row with a flanged cup |
| TSL | Single-row with the DUO-FACE Plus contact seal; the seal assembly has its own part number, printed in brackets (e.g. LM11900EA) |
| J.. / JF.. / JD.. | Metric-series pair designations (J prefix), e.g. JF6049/JF6010 |
Internal design
| X | External dimensions to ISO (the 32xxx / 33xxx metric series) |
Other features
| B | Printed design suffix (e.g. 32206B), kept verbatim |
Good to Know
- The type code 3 and the two-digit dimension series lead the basic designation: 302xx and 303xx are the light and medium single row series, 313xx is a steep-angle series, 320xx/322xx/323xx are the wide series and 329xx/330xx/331xx/332xx the extra-wide ones. The last two digits are the bore code.
- ISO 355 also defines alphanumeric dimension plans (2AB, 2CC, …). Schaeffler (FAG) and NSK print these T dimension-plan codes directly as the designation (T2ED020, T7FC045) for their ANSI/ABMA inch sizes, so the same size can appear as a plan code at one brand and as a cone/cup pair at another.
- The same bearing is written differently by each brand: 32206 → SKF 32206, Schaeffler (FAG) 32206-B-XL, NSK HR32206C / HR32206J, NTN 4T-32206, Timken 32206. The suffixes describe genuine design differences (contact angle, internal design, X-life), not different sizes.
- Inch (ANSI/ABMA) sizes are pairs: the cone and the cup are separate orderable parts and one cone can be matched with several cups (NSK prints 07098/07204 and 07098/07205), so the designation is the pair. SKF abbreviates the cup to its trailing digits, Schaeffler (FAG) joins the pair with a hyphen after a K, and NTN prefixes the pair with 4T-.
- X marks a design with ISO boundary dimensions (32004 X, HR32004XJ, 32004X): it is a different design from the older non-ISO boundary size, not a different bore.
- The single-row product tables carry no cage column, and the catalogs print the same size with several cage options, so this dataset leaves the cage field empty rather than guessing.
- Timken publishes no speed ratings for single-row tapered rollers, so no speed values are given for that brand; SKF and Schaeffler (FAG) publish reference + limiting speeds, NSK and NTN grease / oil speeds.
- Timken TSL (DUO-FACE Plus) is the sealed version of an open cone/cup pair: it uses the same cone and cup but adds a seal assembly (with its own part number), so the sealed width can be slightly larger than the open bearing of the same size.
- A matched pair (SKF /DF face-to-face, /DB back-to-back, /DTC.. tandem) is two single row bearings supplied as one pre-adjusted assembly, so it is catalogued as its own bearing: the entry keeps the single row row-type and records the printed arrangement (/DF, /DB, /DTC10, …), while the load ratings and speeds are those of the pair. The double row designs are separate bearings in their own right: SKF TDO / TDI (row type Double Row, assembly designations such as BT2B 332767 A) and NSK KBE (for example HR40KBE42+L, where B2 is the overall width) each appear under their own printed designation.
- 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 →
