Designation Systems / Deep Groove Ball Bearings
Deep Groove Ball Bearing Designation System
A bearing designation consists of a basic designation (series + bore code) plus optional prefixes and suffixes that describe material, seals, cage, clearance and other features. Each manufacturer publishes its own designation system; the tables below put the five major brands side by side for deep groove ball bearings.
Anatomy of a Designation
W 6205-2RS1 C3
Example shown in SKF style
WPrefixesPrefix — stainless steel bearing, metric dimensions
6205Basic designation — 62 (light) series, bore code 05 = 25 mm
-2RS1Seals, shields & snap ringsSeal suffix — contact rubber seals on both sides
C3Clearance & accuracyClearance suffix — radial internal clearance greater than Normal
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
SKF
Prefixes
| W | Stainless steel, metric dimensions |
| D/W | Stainless steel, inch dimensions |
| WBB1 | Stainless steel, metric, not per ISO dimension series |
| ICOS- | Oil sealed bearing unit |
Internal design
| A, AA, C, D | Deviating or modified internal design |
| E | Reinforced ball set |
Seals, shields & snap rings
| -Z / -2Z | Metal shield on one / both sides |
| -RZ / -2RZ | Non-contact seal (NBR) on one / both sides |
| -RS1 / -2RS1 | Contact seal (NBR) on one / both sides |
| -RSH / -2RSH | Contact seal (NBR) on one / both sides |
| -RSL / -2RSL | Low-friction seal (NBR) on one / both sides |
| -RS2 / -2RS2, -RSH2 / -2RSH2 | Contact seal (FKM) on one / both sides |
| N | Snap ring groove in the outer ring |
| NR | Snap ring groove with snap ring |
| -ZNR / -2ZNR | Shield(s) plus snap ring groove with snap ring |
| N1 | One locating slot (notch) in the outer ring side face |
| R | Flanged outer ring |
| X | Boundary dimensions not per ISO dimension series |
Cage
| (none) | Stamped steel cage, ball centred |
| M | Machined brass cage, ball centred |
| MA(S) / MB(S) | Machined brass cage, outer / inner ring centred |
| TN | PA66 cage, ball centred |
| TN9 | Glass fibre reinforced PA66 cage |
| TNH | Glass fibre reinforced PEEK cage |
Clearance & accuracy
| C2 | Clearance smaller than Normal |
| CN | Normal clearance (usually omitted) |
| C3 | Clearance greater than Normal |
| C4 / C5 | Clearance greater than C3 / C4 |
| P5 / P6 | Tolerance class P5 / P6 |
| P52 / P62 / P63 | Combined class + clearance (P5+C2, P6+C2, P6+C3) |
Heat stabilization
| S0 | Rings stabilized for operating temperatures up to 150 °C |
| S1 | Rings stabilized for operating temperatures up to 200 °C |
Lubrication
| GJN, HT, LHT23, LT, MT33, MT47, WT, GE2 | Grease suffixes; a trailing digit (0-9) gives the fill amount from 5-10 % up to 70-100 % of free volume |
NSK
Seals, shields & snap rings
| Z / ZZ | Steel shield on one / both sides |
| V / VV | Rubber non-contact seal on one / both sides |
| DU / DDU | Rubber contact seal on one / both sides |
| N | Snap ring groove on the outer ring |
| NR | Snap ring groove with locating snap ring |
Cage
| (none) | Pressed steel cage |
| W | Pressed steel cage |
| M | Machined brass cage |
| T | Synthetic resin cage |
Clearance & accuracy
| C2 | Clearance less than normal |
| CN | Normal clearance (omitted) |
| C3 | Clearance greater than normal |
| C4 / C5 | Clearance greater than C3 / C4 |
| CM | Radial clearance for electric-motor bearings |
| P6 / P5 / P4 / P2 | Accuracy ISO class 6 / 5 / 4 / 2 |
Heat stabilization
| X26 | Dimensional stabilization for 150 °C working temperature |
| X28 | Dimensional stabilization for 200 °C working temperature |
| X29 | Dimensional stabilization for 250 °C working temperature |
Lubrication
| NS7 | NS Hi-Lube grease |
| PS2 | Multemp PS No.2 grease |
| S2 | Alvania Grease S2 |
| ENS | ENS grease |
Schaeffler (FAG)
Internal design
| C | Generation C (improved internal design), standard |
Seals, shields & snap rings
| -2Z / -Z | Non-contact sealing shield (sheet metal) on both / one side |
| -2RZ / -RZ | Non-contact seal (rubberised gap seal) on both / one side |
| -2RSR / -RSR | Contact seal (lip seal) on both / one side |
| -2HRS | Contact seal (lip seal) both sides, Generation C standard |
| -2BRS / -BRS | Non-contact labyrinth seal, Generation C |
| -2ELS / -ELS | Contact seal (lip seal), Generation C, by agreement |
Cage
| (none) | Sheet steel cage |
| Y | Sheet brass cage |
| M | Solid brass cage, ball-guided |
| MA / MB | Solid brass cage, guided on outer / inner ring rib |
| TVH | Glass fibre reinforced PA66 cage |
Clearance & accuracy
| C2 | Radial internal clearance smaller than normal |
| C3 | Radial internal clearance larger than normal |
| C4 | Radial internal clearance larger than C3 |
| CM | Radial internal clearance more closely toleranced than normal |
Heat stabilization
| S0 | Dimensionally stabilised up to +150 °C |
| S1 | Dimensionally stabilised up to +200 °C |
| S2 | Dimensionally stabilised up to +250 °C |
NTN
Prefixes
| F- | Stainless steel bearing |
| E- | Case hardened (carburizing) steel bearing |
| TS2- / TS3- / TS4- | Dimension stabilized for high temperature use (to 160 / 200 / 250 °C) |
Seals, shields & snap rings
| Z / ZZ | Steel shield on one / both sides |
| LB / LLB | Synthetic rubber non-contact seal on one / both sides |
| LH / LLH | Synthetic rubber low-torque seal on one / both sides |
| LU / LLU | Synthetic rubber contact seal on one / both sides |
| N | Snap ring groove on the outer ring |
| NR | Snap ring groove with snap ring |
Cage
| (none) | Pressed steel cage |
| T2 | Resin cage |
| L1 | High strength machined brass cage |
| G1 / G2 | High strength machined brass rivetless cage |
Clearance & accuracy
| C2 | Internal clearance less than normal |
| (CN) | Normal clearance (not indicated) |
| C3 | Internal clearance greater than normal |
| C4 / C5 | Internal clearance greater than C3 / C4 |
| CM | Radial internal clearance for electric motor use |
| P6 / P5 / P4 / P2 | Tolerances JIS Class 6 / 5 / 4 / 2 |
Lubrication
| /2AS | Alvania Grease S2 |
| /3AS | Alvania Grease S3 |
| /8A | Alvania EP Grease 2 |
| /5K | Multemp SRL grease |
| /LP03 | Solid grease |
Timken
Seals, shields & snap rings
| -Z / -ZZ | One shield / two shields |
| -RS / -2RS | One contact seal / two contact seals |
| -RZ / -2RZ | One non-contact seal / two non-contact seals |
| -N | Snap ring groove in the outer ring |
| -NR | Snap ring groove with snap ring |
Cage
| (none) | Standard cage |
| M | Brass cage |
| TN1 | Polymer cage |
Clearance & accuracy
| C2 | Tight internal clearance |
| C0 / (blank) | Normal internal clearance |
| C3 | Loose internal clearance |
| C4 / C5 | Extra loose / extra-extra loose internal clearance |
Series names
| 618 | extra-ultra-light |
| 619 | ultra-light |
| 160 | extra-light thin-type |
| 60 | extra-light |
| 62 | light |
| 63 | medium |
| 64 | heavy |
| 620 | light wide-type |
| 630 | medium wide-type |
Good to Know
- NSK and NTN write the 618xx / 619xx series as 68xx / 69xx (e.g. 61805 = NSK/NTN 6805).
- NTN small sizes may carry special suffixes not in the general table (e.g. 6805JR, 16001JRX).
- Schaeffler offers further special designs (stainless steel, high-speed variants) by agreement; see Schaeffler medias for the complete list.
- Availability of a suffix varies by size — always confirm the exact designation in the manufacturer's current catalog.
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 →
