# Timken 3MM9318WI QUM Super Precision Angular Contact Ball Bearing, Quadruplex Medium Preload, ABEC 7 - MROSupply.com

***Timken 3MM9318WI QUM super precision angular contact ball bearing, quadruplex set with medium preload. ABEC 7 (P4S) precision class for high-rigidity machine tool spindles and precision grinding applications requiring exceptional rotational accuracy and load capacity.***



## Product details:

- Catalog number: 3MM9318WI QUM
- SKU: 5115833
- Call for Pricing - 888-671-2883
- Shipping: ***FREE SHIPPING***  ON ORDERS OVER $100
- Typically Ships in: 1 day
- Brand: [Timken](https://www.mrosupply.com/brands/timken/)
- Category: 
    - [Single Row Angular Contact Bearings](htts://www.mrosupply.com/bearings/ball-bearings/angular-contact-ball-bearings/single-row-angular-contact-bearings/)
    - [Angular Contact Ball Bearings](htts://www.mrosupply.com/bearings/ball-bearings/angular-contact-ball-bearings/)
    - [Ball Bearings](htts://www.mrosupply.com/bearings/ball-bearings/)
    - [Bearings](htts://www.mrosupply.com/bearings/)
- Unit of measure: each
- Weight: 5.053 lb
- Returns: Yes


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


## Product attributes;

  
- 0.7087 in C0 - Static Radial Rating (per row): 41200 N
  

  
- 2.8348 in World part number: 71918E-T-P4S-QUM
  

  
- 3.82 in Limiting Speed (Grease) (per row): 9300 rpm Limiting speed (oil):18600 rpm Manufacturing part number:3MM9318WI QUM O.D. (in):125 mm 4.9213 Outer ring backing diameter:118.5 mm
  

  
- 4.660 in Precision rating: ISO P4S (ABEC 7/9) Rows per set:Quadruplex Total width:72.000 mm
  

  
- 8670 lbf Cage type: CR - Phenolic Outer Land Riding Cage Contact angle:25 Design units:Metric Inner ring backing diameter:97 mm
  

  
- 9270 lbf C1 ISO - Dynamic Radial Rating (per row): 38500 N
  

  
- Ball type: Steel Bearing width:18 mm
  

  
- Ball Type: STEEL
  

  
- Bearing Width: 18 mm 0.7087 in
  

  
- Bore: 90 mm
  

  
- C0 - Static Radial Rating (per row): 41200 N 9270 lbf
  

  
- C1 ISO - Dynamic Radial Rating (per row): 38500 N 8670 lbf
  

  
- Cage Type: CR - Phenolic Outer Land Riding Cage
  

  
- Ce - Dynamic Radial Rating (per row): 42400 N 9540 lbf
  

  
- Contact Angle: 25 º
  

  
- d - Bore: 90 mm
  

  
- D - Outer Diameter: 125 mm 4.9213 in
  

  
- da - Inner Ring Backing Diameter: 97.0 mm 3.82 in
  

  
- Da - Outer Ring Backing Diameter: 118.5 mm 4.660 in
  

  
- Design Units: Metric
  

  
- DOuter Ring Backing Diameter: 118.5 mm 4.660 in
  

  
- Dynamic Radial Rating (per row): 42400 N 9540 lbf
  

  
- I.D.: 90 mm
  

  
- Inner Ring 'To Clear' Radius: 1 mm 0.039 in
  

  
- Inner Ring Backing Diameter: 97.0 mm 3.82 in
  

  
- Limiting Speed (Grease) (per row): 9300 rpm
  

  
- Limiting Speed (Oil): 18600 rpm
  

  
- Manufacturing Part Number: 3MM9318WI QUM
  

  
- Outer Diameter: 125 mm 4.9213 in
  

  
- Outer Ring 'To Clear' Radius: 1 mm 0.039 in
  

  
- Precision Rating: ISO P4S (ABEC 7/9)
  

  
- R - Inner Ring "To Clear" Radius: 1 mm 0.039 in
  

  
- r - Outer Ring "To Clear" Radius: 1 mm 0.039 in
  

  
- Rows per Set: Quadruplex
  

  
- Static Radial Rating (per row): 41200 N 9270 lbf
  

  
- Total Width: 72.000 mm 2.8348 in
  

  
- World Part Number: 71918E-T-P4S-QUM
  
## Product documents / software:

- [Catalog](https://documents.mrosupply.com/product_documents/50/60/5060627/Machine-Tool-Applications-Catalog_R9rBZA3.pdf)

## Product's reviews:
- Best company to buy from - I always buy from MRO is a very reliable company to work with




## 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.