25581 Bearing Dimensions
25581 inch tapered roller bearing cone, paired with the 25520 cup: 45.618 mm (1.796 in) bore, 82.931 mm OD, 23.812 mm width (FULI catalog). Quote.
25581 specifications
| Cone bore d | 45.618 mm (1.796 in) |
|---|---|
| Cone width B | 25.4 mm |
| Matching cup | 25520 |
| Cup outside diameter D | 82.931 mm (3.265 in) |
| Total width T | 23.812 mm (0.937 in) — assembled width of cup and cone |
| Seal / shield options | Open (cup and cone, no seals) |
| Material | GCr15 chrome bearing steel (rings and rolling elements) |
| Radial clearance | Set during mounting (adjustable, not a C-class value) |
| Load ratings | See the cone and cup pairs table below |
25581 cone and cup pairs
| Cone | Cup | Bore d | OD D | Width T | Cr (kN) | C0r (kN) |
|---|---|---|---|---|---|---|
| 25581 | 25520 | 45.618 mm (1.796 in) | 82.931 mm (3.265 in) | 23.812 mm (0.937 in) | 77.9 | 100.1 |
Dimensions from FULI's catalog. A cone (inner ring with rollers and cage) and a cup (outer ring) make up one bearing; the pairs above are the matching numbers listed in FULI's catalog. Values from FULI's catalog; confirm for your application.
How to read the 25581 designation
| Segment | Meaning |
|---|---|
| 2 | Spherical roller bearing (double row, self-aligning) |
| 55 | Dimension series 55 |
| 81 | Bore code 81 → 45.618 mm bore. ISO bore code (00–03 = 10/12/15/17 mm; 04 and above = code × 5 mm). |
25581 interchange
25581 is an inch tapered roller bearing cone. Inch tapered roller bearings are ordered by cone number and cup number. Most makers use the same cone and cup numbers for the same size, but always check the cup number as well. Send us the numbers on your old bearing and we confirm the match before quoting.
Brand names are trademarks of their respective owners. FULI is not affiliated with, authorized by or endorsed by these companies. Part numbers are shown for interchange reference only. FULI dimensions, load ratings and speeds come from the FULI catalog.
25581 compared with nearby cone sizes
The 25581 cone has a 45.618 mm (1.796 in) bore and a cone width of 25.4 mm. FULI's catalog pairs it with cup 25520 (82.931 mm outside diameter, 23.812 mm total width).
The next smaller cone on this site is LM603049, with a 45.242 mm bore (0.38 mm smaller) and cup LM603012.
The next larger is 25590, with a 45.618 mm bore (0 mm larger) and cup 25522.
Cup 25520 is also listed with 25580 and 25590, so the same housing bore can take a different cone if the shaft size changes.
The metric tapered bearing on this site closest in bore is 32009 (45 × 75 × 20 mm). Its sizes differ from the 25581 pair, so the two are not interchangeable; it is given only as a size reference.
| Cone | Cup | d × D × T | Cr (kN) |
|---|---|---|---|
| 460 | 453A | 44.45 × 107.95 × 27.783 mm | 118.2 |
| LM102949 | LM102910 | 45.242 × 73.431 × 19.558 mm | 55.6 |
| LM603049 | LM603012 | 45.242 × 77.788 × 21.43 mm | 57.4 |
| 25581 | 25520 | 45.618 × 82.931 × 23.812 mm | 77.9 |
| 25590 | 25522 | 45.618 × 83.058 × 23.876 mm | 78.3 |
| 28580 | 28521 | 50.8 × 92.075 × 24.6 mm | 86.3 |
| 368 | 362A | 50.8 × 88.9 × 20.638 mm | 75.8 |
Sizes and Cr from FULI's catalog; — = not listed on this site.
25581 load ratings
25581/25520 has a dynamic load rating Cr of 77.9 kN and a static rating C0r of 100.1 kN in FULI's catalog. The ratings belong to the cone and cup as a pair; a different cup changes them.
Speed limits and weights for inch cones are not listed in the catalog; ask us and we send them with the quotation.
Values from FULI's catalog; confirm for your application.
25581 size in inches and millimetres
25581 is made to inch sizes. The 45.618 mm bore is 1.7960 in; the nearest common fraction is 1-13/16 in (46.04 mm). The millimetre values in the catalog are conversions of the inch sizes.
| Dimension | Millimetres | Inches |
|---|---|---|
| Cone bore d | 45.618 mm | 1.7960 in |
| Cup outside diameter D (25520) | 82.931 mm | 3.2650 in |
| Total width T | 23.812 mm | 0.9375 in |
| Cone width B | 25.4 mm | 1.0000 in |
| Cup width C | 19.05 mm | 0.7500 in |
Converted at 1 in = 25.4 mm and rounded to four decimals.
Mounting 25581 (general guidance)
General guidance, not a FULI specification: on a turning shaft the cone is a tight fit on the shaft and the cup a lighter fit in the housing, so the cup can be moved when the bearing pair is adjusted. Inch bearing fits are given as shaft and housing limits in inches in the bearing makers' tables; follow the drawing of your machine.
Tapered roller bearings carry radial load and axial load in one direction, so 25581 is normally used as one of a pair, and the end play or preload is set at mounting.
If the outer ring turns and the shaft stands still, as in an idler pulley or a wheel hub, the fits are reversed: the housing gets the interference fit (for example N7 or P7) and the shaft a sliding one (g6 or h6).
Grease for 25581
FULI supplies tapered roller bearings rust-protected and normally without grease; grease is packed in when the bearing is mounted. Relubricating 25581/25520 from the side takes about 9.87 g each time by the formula in our grease calculator: 0.005 × D × T = 0.005 × 82.93 × 23.81.
How FULI supplies 25581
25581 is supplied as a cone, as a cup or as a complete cone and cup pair, as your order states. Where an order states a requirement for the total width T (23.812 mm for 25581/25520), each set is checked on a height gauge before packing.
Rings are marked with a brand you are authorised to use, with the FULI brand, or left neutral, as your order states. The box is printed with the model, precision class and brand.
Inquiries that give only one number are the usual cause of a wrong quote, so write both the cone and the cup number, for example 25581/25520.
Tools and guides for 25581
Typical applications
- Vehicle wheel hubs and axles
- Gearboxes and reducers
- Agricultural machinery
- Conveyor pulleys
FAQ
What size is 25581 in mm?
The 25581 cone has a 45.618 mm bore (1.796 in). With cup 25520 the bearing is 45.618 × 82.931 × 23.812 mm (d × D × T).
What is the difference between 25581 and 25590?
25590 has a 45.618 mm bore against 45.618 mm for 25581, and pairs with cup 25522 (45.618 × 83.058 × 23.876 mm) instead of 25520 (45.618 × 82.931 × 23.812 mm). The two are not interchangeable; order by the numbers on the old cone and cup.
How much grease does 25581/25520 need?
About 9.87 g each time it is relubricated from the side (0.005 × 82.93 × 23.81). FULI ships it rust-protected without grease, so the first fill is made at mounting.
Which cup goes with the 25581 cone?
FULI's catalog pairs the 25581 cone with cup 25520. Tell us whether you need the cone, the cup or both when you send the inquiry.
Is 25581 the same size across brands?
25581 is an inch tapered roller bearing cone number. Most makers use the same cone and cup numbers for the same size, but check the cup number too. Send us the numbers on your old bearing and we confirm the match.