6311 bearing: 55 × 120 × 29 mm
Bearings › 6311
A 6311 is a deep groove ball bearing, 55 mm bore, 120 mm outside diameter, 29 mm wide. Variants: 6311-2RS (rubber sealed), 6311-ZZ (metal shields), 6311 open.
| Bore | 55 mm |
|---|---|
| Outside diameter (OD) | 120 mm |
| Width | 29 mm |
| Dynamic load rating C | 74.1 kN |
| Static load rating C0 | 45 kN |
| Limiting speed | 8 000 r/min |
| Weight | 1.34 kg |
Ratings and weight: SKF product page, skf.com, read 2 Oct 2026, designation 6311. Limiting speed as SKF gives it.
Open 6311 in BenchsmithAdd to order list
What the number means
6 | Deep groove ball bearing |
3 | Medium series |
11 | Bore 11 × 5 = 55 mm |
Ask for
- 6311-2RS: rubber sealed both sides. Other brands: SKF 6311-2RSH, FAG 6311-2RSR, NSK 6311DDU, NTN 6311LLU, Koyo 6311-2RS.
- 6311-ZZ: metal shields both sides. Other brands: SKF 6311-2Z, FAG 6311-2ZR, NSK 6311ZZ, NTN 6311ZZ, Koyo 6311ZZ.
- 6311: open, no seals or shields.
Add C3 for electric motors and anything that runs hot.
About the 63 series
Same bore as the 62, but a bigger OD and wider. Heavier load, same shaft. You'll find them in pumps, compressors and the drive end of bigger motors.
If a 62 keeps failing and the housing has room, a 63 is the usual upgrade. Check the housing bore first; it won't fit a 62's seat.
Same bore, different size
One size up or down
Every bearing 55 × 120 × 29 mm: 55 × 120 × 29 mm bearings. Measured a bearing with no number on it? Type the bore, OD and width into Benchsmith → Find → Bearing.