BEARINGDEXCylindrical roller, NJ
NJ311 bearing
55 mm bore, 120 mm outside diameter, 29 mm width (2.1654 × 4.7244 × 1.1417 in).
Dimensions
| mm | inch | |
|---|---|---|
| Bore d | 55 | 2.1654 |
| Outside diameter D | 120 | 4.7244 |
| Width B | 29 | 1.1417 |
Quick numbers
| Pitch diameter dm | 87.5 mm |
| Section height (D − d)/2 | 32.5 mm |
| n·dm at 1,800 rpm | 157,500 |
| n·dm at 3,600 rpm | 315,000 |
Compare against the maker's limiting speed. Speed calculator · L10 life
What the number means
NJCylindrical roller. One rib on the inner ring locates the shaft in one direction.
3Diameter series 3: medium
11Bore code 11 × 5 = 55 mm
Same size, different bearing
These share the 55 × 120 × 29 mm envelope but carry load differently. They aren't drop-in swaps.