# NTN BL311Z Deep Groove Ball Bearing - 55 mm Bore, Single Shielded, Medium Series - MROSupply.com

***NTN BL311Z is a medium series single-row deep groove ball bearing with a 55 mm straight bore. It features a single shielded design for moderate contamination protection. Suitable for general industrial rotating equipment including electric motors, pumps, and fans.***



## Product details:

- Catalog number: BL311Z
- SKU: 276268
- Price: ***$170.08*** Each
- Shipping: ***FREE SHIPPING***  ON ORDERS OVER $100
- Typically Ships in: 1 day
- Brand: [NTN Bearing](https://www.mrosupply.com/brands/ntn-bearing/)
- Category: 
    - [BL3 Series Ball Bearings](htts://www.mrosupply.com/bearings/ball-bearings/bl3-series-ball-bearings/)
    - [Ball Bearings](htts://www.mrosupply.com/bearings/ball-bearings/)
    - [Bearings](htts://www.mrosupply.com/bearings/)
- Unit of measure: each
- Weight: 3.230 lb
- UPC: 4547359029499


## Product images:
- https://static.mrosupply.com/images/noimage.webp


## Product attributes;

  
- B (in): 1.1417
  

  
- Ball Material: Steel
  

  
- Ball material: Steel
  

  
- Bore Type: Round
  

  
- Bore type: Round
  

  
- Cage Material: Steel
  

  
- Cage material: Steel
  

  
- Cage Type: Pressed
  

  
- Cage type: Pressed
  

  
- Configuration: One
  

  
- D (in): 4.7244
  

  
- d (in): 2.1654
  

  
- Da max: 4.3701 in
  

  
- da max: 2.9134 in
  

  
- da min: 2.5197 in
  

  
- Enclosure: Single Shielded
  

  
- Factor: 111.0
  

  
- I.D.: 55 mm
  

  
- Limiting Speed - Grease: 5200 RPM
  

  
- Limiting speed - grease: 5200 RPM
  

  
- Limiting Speed - Oil: 6100 RPM
  

  
- Limiting speed - oil: 6100 RPM
  

  
- Material: High carbon chrome steel
  

  
- O.D.: 120 mm
  

  
- Operating Temperature Range: -40 to 250 °F
  

  
- Operating temperature range: -40 to 250 ºF
  

  
- Precision: ISO class 0
  

  
- r (in): 0.0787
  

  
- Radial Internal Clearance: CN
  

  
- Radial internal clearance: CN
  

  
- ras max: 0.0787 in
  

  
- Type: Deep Groove Ball Bearing
  
## Product documents / software:

- [Drawing](https://documents.mrosupply.com/product_documents/50/48/5048099/1151_S_rexnKIK.png)
## Alternate products to `NTN BL311Z Deep Groove Ball Bearing - 55 mm Bore, Single Shielded, Medium Series - MROSupply.com`:
- [SKF 6311-2Z/C3 55mm bore deep groove ball bearing, double shielded with steel shields on both sides and C3 greater-than-normal clearance. It features a pressed steel cage and is constructed from standard bearing steel. Suitable for electric motors, pumps, fans, and general industrial applications.](https://www.mrosupply.com/products/320359/as-markdown/)
- [SKF 6311 2ZJEM is a 55mm bore deep groove ball bearing, double shielded with metal shields, C3 clearance, and a machined brass cage. Suitable for electric motors, pumps, and general industrial applications.](https://www.mrosupply.com/products/320869/as-markdown/)
- [SKF 6311-2Z deep groove ball bearing, 55mm bore, 4.724 in OD, double shielded with steel shields both sides. Normal internal clearance, pressed steel cage. Suitable for electric motors, pumps, fans, and general industrial applications.](https://www.mrosupply.com/products/319305/as-markdown/)
- [SKF 6311-Z is a 55mm bore deep groove ball bearing with a steel shield on one side. It features a sheet metal cage and normal internal clearance. Suitable for electric motors, pumps, and general industrial applications.](https://www.mrosupply.com/products/320979/as-markdown/)
- [NACHI 6311ZZEC3 Deep Groove Ball Bearing Single Row 55X120X29MM Two Shields Steel Cage C3 Clearance](https://www.mrosupply.com/products/696388/as-markdown/)
- [Koyo 6311 ZZ is a 63 series single-row deep groove ball bearing with a 55 mm bore, 120 mm OD, and 29 mm width. It features double steel shields (ZZ) and a pressed steel cage. Designed for radial and moderate axial loads in electric motors, pumps, fans, and general industrial rotating equipment.](https://www.mrosupply.com/products/1494976/as-markdown/)
- [NSK 6311ZZC3 shielded deep groove ball bearing with 55 mm bore. Double metal shields (ZZ) protect against contaminants, and C3 clearance provides a looser internal fit for thermal expansion. Suitable for electric motors, pumps, fans, and general industrial applications.](https://www.mrosupply.com/products/5034293/as-markdown/)
- [FAG 6311.2ZR deep groove ball bearing with 55mm bore and 2 1/6 in ID. Double shielded for contamination protection. Ball guided cage ensures smooth operation. Suitable for high-speed applications requiring low friction and reliable performance.](https://www.mrosupply.com/products/2176120/as-markdown/)






## FAQ:

- How do I choose the right type of bearing for my application?: Start with the load and how it’s applied. You need to know if you’re dealing with radial loads, axial loads, or a mix of both. Then look at speed, operating environment, and space constraints.
For example, ball bearings are great for high speed and lighter loads, while roller bearings handle heavier loads but usually at lower speeds. If there’s contamination, moisture, or heat involved, you may need sealed bearings or specific materials.
In most cases, the right choice comes down to matching load type, speed, and environment to the bearing design.


- What is the difference between deep groove and angular contact ball bearings?: Deep groove ball bearings are the most common type. They’re designed to handle mainly radial loads, but they can also take some axial load in both directions. They’re simple, versatile, and used in everything from motors to conveyors.
Angular contact ball bearings are built for combined loads, especially where there’s significant axial force in one direction. They’re often used in pairs and are common in higher precision or higher load applications like pumps and gearboxes.
If your load is mostly radial, go deep groove. If axial load matters more, angular contact is usually the better choice.