Specification summary of DIN 720 (tapered roller bearings) as it applies to inch series tapered roller bearing cup and cone sets: what the document fixes, where its scope ends, the ISO, DIN and GB/T equivalents, and the dimensions supplied to it.
DIN 720 — Scope
DIN 720 is the German standard for metric tapered roller bearings, covering the same 30000-series envelope as ISO 355: bore d, outside diameter D, the assembled width T and the individual cone and cup widths B and C.
What DIN 720 Does Not Fix
It does not decide the mounted setting. A tapered roller bearing is adjusted against its opposing bearing to an endplay or a preload on assembly, and that figure comes from the application, not from a dimensional standard.
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 DIN 720
| Designation | Cone (inner) part number | Cup (outer) part number | Bore d (in) | Bore d (mm) | Outer diameter D (in) | Outer diameter D (mm) | Assembled width T (in) | Assembled width T (mm) |
|---|---|---|---|---|---|---|---|---|
| LM11749/LM11710 | LM11749 | LM11710 | 0.6875 | 17.462 | 1.7810 | 45.237 | 0.6100 | 15.494 |
| L44649/L44610 | L44649 | L44610 | 1.0625 | 26.988 | 1.9800 | 50.292 | 0.5600 | 14.224 |
| LM67048/LM67010 | LM67048 | LM67010 | 1.2500 | 31.750 | 2.3280 | 59.131 | 0.6600 | 16.764 |
| LM68149/LM68110 | LM68149 | LM68110 | 1.3780 | 35.000 | 2.3280 | 59.131 | 0.6600 | 16.764 |
| 15123/15245 | 15123 | 15245 | 1.2500 | 31.750 | 2.4410 | 62.000 | 0.7500 | 19.050 |
| 25877/25821 | 25877 | 25821 | 1.3750 | 34.925 | 2.8750 | 73.025 | 0.8750 | 22.225 |
| HM88649/HM88610 | HM88649 | HM88610 | 1.3750 | 34.925 | 2.5625 | 65.088 | 0.8125 | 20.638 |
| JLM104948/JLM104910 | JLM104948 | JLM104910 | 1.9685 | 50.000 | 3.2283 | 82.000 | 0.8465 | 21.500 |
National Equivalents
ISO 355 and its identical adoption DIN ISO 355 are the current international references; GB/T 297 is the Chinese equivalent.
This product is supplied against ANSI/ABMA 19.2 (TS inch series), which names the documents it is made to.
When to Cite DIN 720
DIN 720 remains in daily use in European mechanical engineering and on legacy drawings, and it is what many German-language datasheets cite. For a new design the ISO document is the better contractual reference, with the DIN number carried alongside it so that the drawing reads the same to everyone.
