78FC55400AW bearings ( 390 mm x 550 mm x 400 mm) have the advantages of Extremely high radial load capacity, high rigidity, separable design, and are therefore widely used in the metallurgical rolling mills, large gearboxes, and heavy-duty extrusion presses.

| Part Number | 78FC55400AW |
| Interchangeable | KOYO 78FC55400AW |
| Desgin Figure | 2-3 |
| Cage | Machined brass cage |
| Radial internal clearance | C3 |
| Seal | Open |
| Bearing Type | Four-row cylindrical roller bearing for cold rolling mill, hot rolling mill, billet mill |
| Equivalent | FCD78110400 (China) 390RV5521 (NSK) 78FC55400AW (KOYO) |
| Design type | Outer ring with rib, Two inner rings |
| Bearing Weight [lb] | 652.562 |
| d φ Inside [inch] | 15.354 |
| D Φ Outside [inch] | 21.654 |
| B Width [inch] | 15.748 |
| Fw Raceway diameter inner ring [inch] | 17.087 |
| C [inch] | 15.748 |
| r min Chamfer outer ring | 5 mm |
| r1 min Chamfer inner ring | SP mm |
| Cr Radial Dynamic [lbf] | 1153224 |
| C0r Radial Static [lbf] | 2787520 |
| Mounting dimensions | |
| da min shaft [inch] | 16.142 |
| Da max housing [inch] | 20.787 |
| Da min housing [inch] | 20.079 |
| ra max Fillet radius [inch] | 0.157 |
| rb max Fillet radius [inch] | 0.157 |
The 78FC55400AW Four-row cylindrical roller bearings mainly consist of an inner ring, an outer ring, four rows of cylindrical rollers, a cage, and a spacer. Common structures use a configuration of double outer rings (each with double raceways) and a single inner ring (with four raceways), or an interchangeable combination of inner and outer rings. Axial positioning and load distribution are achieved through the spacer.
The advantages of four-row cylindrical roller bearings are their extremely high radial load capacity, high rigidity, and the line contact between the rollers and raceways, resulting in a low coefficient of friction and allowing for high-speed operation under heavy loads. They can also be used as floating end bearings, capable of withstanding axial displacement caused by thermal expansion, and are easy to install and maintain.















