# NTN 51311 Thrust Ball Bearing - 55 mm Bore, Single Direction, Straight Bore - MROSupply.com

***NTN 51311 single direction thrust ball bearing with a 55 mm straight bore. Designed for axial loads in one direction, this bearing features a shaft washer, housing washer, and ball and cage assembly. Suitable for applications such as machine tool spindles, gearboxes, and vertical shafts.***



## Product details:

- Catalog number: 51311
- SKU: 283279
- Price: ***$109.59*** Each
- Shipping: ***FREE SHIPPING***  ON ORDERS OVER $100
- Typically Ships in: 1 day
- Brand: [NTN Bearing](https://www.mrosupply.com/brands/ntn-bearing/)
- Category: 
    - [Ball Thrust Bearings](htts://www.mrosupply.com/bearings/ball-bearings/ball-thrust-bearings/)
    - [Ball Bearings](htts://www.mrosupply.com/bearings/ball-bearings/)
    - [Bearings](htts://www.mrosupply.com/bearings/)
- Unit of measure: each
- Weight: 2.820 lb
- UPC: 4547359307122


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


## Product attributes;

  
- 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): 4.1339
  

  
- d (in): 2.1654
  

  
- d1: 4.1339 in
  

  
- D1: 2.2441 in
  

  
- Da max: 3.3465 in
  

  
- da min: 3.3465 in
  

  
- Dynamic Load Rating: 26800 lbf
  

  
- Dynamic load rating: 26800 lbf
  

  
- Enclosure: Open
  

  
- I.D.: 55 mm
  

  
- Limiting Speed - Grease: 1600 RPM
  

  
- Limiting speed - grease: 1600 RPM
  

  
- Limiting Speed - Oil: 2300 RPM
  

  
- Limiting speed - oil: 2300 RPM
  

  
- Material: High carbon chrome steel
  

  
- O.D.: 105 mm
  

  
- Operating Temperature Range: -40 to 250 °F
  

  
- Operating temperature range: -40 to 250 ºF
  

  
- Outside Ring Type: Straight
  

  
- Precision: ISO class 0
  

  
- r (in): 0.0433
  

  
- Radial Internal Clearance: CN
  

  
- Radial internal clearance: CN
  

  
- ras max: 0.0394 in
  

  
- Seal material: None
  

  
- Seal type: None
  

  
- Static Load Rating: 55500 lbf
  

  
- Static load rating: 55500 lbf
  

  
- T (in): 1.3780
  

  
- Type: Thrust Ball Bearing
  
## Product documents / software:

- [Drawing](https://documents.mrosupply.com/product_documents/50/48/5048886/1264_S_mICK0xq.png)
## Alternate products to `NTN 51311 Thrust Ball Bearing - 55 mm Bore, Single Direction, Straight Bore - MROSupply.com`:
- [Rollway 51311 55 mm Bore Size, 105 mm Outside Diameter, Thrust Ball Bearing, 52100 Bearing Steel, Normal Radial Clearance](https://www.mrosupply.com/products/2302326/as-markdown/)
- [SKF 51311 thrust ball bearing, 55mm bore, 2.165 in ID, 4.134 in OD. Sheet metal cage, bearing steel construction, standard clearance. Accommodates axial loads in one direction for moderate-speed applications such as machine tool spindles and gearboxes.](https://www.mrosupply.com/products/320399/as-markdown/)
- [NSK 51311 thrust ball bearing with 55 mm bore. Designed for pure axial loads in vertical-shaft applications such as pumps and turbines. Backed by NSK's precision-bearing engineering heritage.](https://www.mrosupply.com/products/5032864/as-markdown/)
- [FAG 51311 single direction thrust ball bearing with 55mm bore and 105mm OD. Designed for axial loads in one direction, this bearing offers reliable performance in moderate-speed applications. Precision-ground raceways ensure smooth operation. Suitable for various industrial machinery requiring thrust load support.](https://www.mrosupply.com/products/2171538/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.