For 30200 series tapered roller bearings, ISO 355 is one of the controlling documents. The sections below describe its scope, the properties it does NOT decide and which standard does decide them, the equivalent designations, and the full size range.
ISO 355 — Scope
ISO 355 fixes the boundary dimensions of metric tapered roller bearings — bore d, outside diameter D, the assembled width T and the separate cone width B and cup width C — and defines the alphanumeric designation system (for example 30205 in the older series notation) built on the diameter, width and contact-angle series.
What ISO 355 Does Not Fix
It does not fix the load rating, which is ISO 281, nor the mounted setting: a tapered roller bearing is adjusted on assembly to an endplay or a preload, and no standard can decide that figure for your shaft and your temperature rise.
This division of labour is the thing to carry away from any bearing standard. A boundary dimension standard makes bearings interchangeable; it does not make them equivalent. Two bearings of the same designation from different makers mount in the same seat and are not required to have the same load rating, the same internal design, the same cage or the same speed limit.
Dimensions Supplied to ISO 355
| Designation | Bore d (mm) | Outer diameter D (mm) | Assembled width T (mm) | Width B (mm) | Width C (mm) | Contact angle a (deg) | Chamfer r min (mm) |
|---|---|---|---|---|---|---|---|
| 30203 | 17 | 40 | 13.25 | 12 | 11 | 12.95 | 1 |
| 30204 | 20 | 47 | 15.25 | 14 | 12 | 12.95 | 1 |
| 30205 | 25 | 52 | 16.25 | 15 | 13 | 14.04 | 1 |
| 30206 | 30 | 62 | 17.25 | 16 | 14 | 14.04 | 1 |
| 30207 | 35 | 72 | 18.25 | 17 | 15 | 14.04 | 1.5 |
| 30208 | 40 | 80 | 19.75 | 18 | 16 | 14.04 | 1.5 |
| 30209 | 45 | 85 | 20.75 | 19 | 16 | 15.11 | 1.5 |
| 30210 | 50 | 90 | 21.75 | 20 | 17 | 15.64 | 1.5 |
| 30211 | 55 | 100 | 22.75 | 21 | 18 | 15.11 | 2 |
| 30212 | 60 | 110 | 23.75 | 22 | 19 | 15.11 | 2 |
| 30213 | 65 | 120 | 24.75 | 23 | 20 | 15.11 | 2 |
| 30214 | 70 | 125 | 26.25 | 24 | 21 | 15.11 | 2 |
| 30215 | 75 | 130 | 27.25 | 25 | 22 | 16.17 | 2 |
| 30216 | 80 | 140 | 28.25 | 26 | 22 | 15.64 | 2.5 |
| 30217 | 85 | 150 | 30.5 | 28 | 24 | 15.64 | 2.5 |
| 30218 | 90 | 160 | 32.5 | 30 | 26 | 15.64 | 2.5 |
| 30219 | 95 | 170 | 34.5 | 32 | 27 | 15.64 | 3 |
| 30220 | 100 | 180 | 37 | 34 | 29 | 15.64 | 3 |
National Equivalents
DIN ISO 355 is the identical adoption, DIN 720 the older national document for the same bearings, and GB/T 297 the Chinese equivalent. Inch tapered bearings are a separate lineage, covered by ANSI/ABMA 19.2.
This product is supplied against ISO 355 / DIN ISO 355 / GB/T 297, which names the documents it is made to.
When to Cite ISO 355
ISO 355 is the international reference and the right one to cite on a new drawing or a purchase specification. Adding the national equivalents alongside it costs nothing and makes the requirement legible to a supplier working to DIN or to GB/T.
