Which standard answers which question. When a drawing cites a number, or a quotation asks for a class you do not recognise, start here.
Bearing standards fall into four groups, and mixing them up is the most common source of a mismatch between what a customer asked for and what was quoted.
Our catalogue part numbers are dimensioned to the ISO boundary standards, which is why a model crosses cleanly to other makers. Where a customer needs a specific tolerance class or clearance, we state it in writing rather than leaving it to the default.
| Standard | Title | What it covers |
|---|---|---|
| ISO 15 | Radial bearings — Boundary dimensions, general plan | The dimension plan behind 6000 / 6200 / 6300 numbering and every standard bore-OD-width combination. |
| ISO 76 | Rolling bearings — Static load ratings | Defines the basic static load rating C0 and the static safety factor s0. |
| ISO 104 | Rolling bearings — Thrust bearings — Boundary dimensions | The dimension plan for thrust bearings, matching ISO 15 for radial types. |
| ISO 199 | Rolling bearings — Thrust bearings — Tolerances | The thrust equivalent of ISO 492. |
| ISO 281 | Rolling bearings — Dynamic load ratings and rating life | The L10 life equation, the life exponent, and the a1 and aISO adjustment factors. |
| ISO 286-1 / -2 | ISO code system for tolerances on linear sizes | Defines the tolerance unit i, the IT grades and the shaft and housing letter zones used for fits. |
| ISO 355 | Rolling bearings — Tapered roller bearings — Boundary dimensions and series designations | The rule that turns a 30206 or 32210 into a known envelope. |
| ISO 464 | Rolling bearings — Locating snap rings | Dimensions and tolerances for the snap ring groove and the ring itself. |
| ISO 492 | Rolling bearings — Radial bearings — GPS and tolerance values | Bore, outer diameter and runout values for the Normal, 6, 5, 4 and 2 classes. |
| ISO 582 | Rolling bearings — Chamfer dimensions — Maximum values | The r min and r max figures quoted in catalogues next to the corner radius. |
| ISO 1101 | GPS — Geometrical tolerancing | The language of the frame symbols on a bearing drawing: circularity, parallelism, runout. |
| ISO 1132-1 | Rolling bearings — Tolerances — Terms and definitions | Fixes the meaning of every symbol used in the ISO 492 tables. |
| ISO 5753-1 | Rolling bearings — Internal clearance — Radial internal clearance for radial bearings | The C1 / C2 / CN / C3 / C4 / C5 clearance ranges. |
| ISO 5593 | Rolling bearings — Vocabulary | The reference source for the terms used on our glossary page. |
| ISO 15242 series | Rolling bearings — Measuring methods for vibration | How vibration and noise are measured and what the Andreason and BVT values mean. |
| ISO 15243 | Rolling bearings — Damage and failures — Terms, characteristics and causes | The six failure modes: fatigue, wear, corrosion, electrical erosion, plastic deformation, fracture. |
| ISO 6743-9 / ISO 12924 | Lubricants, industrial oils and related products — Classification | ISO 6743-9 classifies greases; ISO 12924 sets the L class requirements for greases. |
| DIN 51825 | Lubricants — Lubricating greases K | The German grease classification, still widely quoted on bearing grease datasheets. |
| ISO 4406 | Hydraulic fluid power — Method for coding the level of contamination by solid particles | The 18/16/13 style cleanliness code that decides whether a lubrication system is fit for a bearing. |
| ISO 20816 | Mechanical vibration — Measurement and evaluation of machine vibration | The successor to ISO 10816 and the acceptance bands used in condition monitoring. |
| DIN 620 | Rolling bearing tolerances | The German tolerance standard behind the P0 / P6 / P5 / P4 / P2 designations. |
| ABMA / ANSI Std 20 | Radial bearings of ball, cylindrical roller and spherical roller types | The source of the ABEC and RBEC precision scales used in North America. |
| JIS B 1514 | Rolling bearings — Tolerances | The Japanese standard, using Class 0 / 6 / 5 / 4 / 2. |
If a specification cites a standard number you do not recognise, send it to us. In most cases the answer is that it belongs to one of the four groups above and maps onto something we hold in stock - for example a bearing marked to DIN 620 P6 is the same accuracy class as ISO 492 Class 6, and a US RBEC 3 roller bearing maps onto the same class for runout purposes.
Where a standard genuinely differs, it is usually in scope rather than in value. That is the case at the top of the ABEC scale, and it is why we recommend confirming the parameter that matters rather than the label on the box.
Send the standard, class or drawing note you are working to and we will tell you what it means and what we can supply against it.