BEARINGDEXDeep groove ball
6311 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
6Deep groove ball
3Diameter series 3: medium. Width series 0 is implied and left off.
11Bore code 11 × 5 = 55 mm
How each brand writes it
Same bearing, every maker's notation| Version | SKF | FAG | NSK | NTN | Koyo | NACHI |
|---|---|---|---|---|---|---|
| Open | 6311 | 6311 | 6311 | 6311 | 6311 | 6311 |
| Shields both sides | 6311-2Z | 6311-2ZR | 6311ZZ | 6311ZZ | 6311ZZ | 6311ZZE |
| Contact seals both sides | 6311-2RSH | 6311-2RSR | 6311DDU | 6311LLU | 6311-2RS | 6311-2NSE |
| Contact seals both sides, C3 | 6311-2RSH/C3 | 6311-2RSR-C3 | 6311DDUC3 | 6311LLUC3 | 6311-2RSC3 | 6311-2NSE C3 Verify |
| Non-contact seals both sides | 6311-2RSL | 6311-2BRS Verify | 6311VV | 6311LLB | 6311-2RU Verify | 6311-2NKE Verify |
| Shields both sides, C3 | 6311-2Z/C3 | 6311-2ZR-C3 | 6311ZZC3 | 6311ZZC3 | 6311ZZC3 | 6311ZZE C3 Verify |
Same size, different bearing
These share the 55 × 120 × 29 mm envelope but carry load differently. They aren't drop-in swaps.