You need to be comprehensive if you wish to be accurate. Here is a start with 11 items to consider:

1. Bearing size, type, and manufacturing location - not all bearings are created equal.

2. Grease type and quantity

3. Bearing seal type and if contact type run-in specifications - sufficient run-in to mimic 3 months of service that polishes any contact members

4. How to apply load that does not influence the test with additional drag conditions that mask the test results.

5. Bearing rotation and its influence with sealing and drag

6. Speed

7. Temperature

8. Application of grease drag as advanced by majjor bearing suppliers: SKF, FAG, NTN, KOYO, ......

9. Statistical regime to obtain representative variance and mean -- what accuracy is desired?

10. Measurements on assembly balance and run-out tolerances (TIR) - testing and specification acceptances.

11. Test environment including dust, moisture, and all of the above.

I suggest you look at what major academic institutions have done. Typically, they are more advanced than idler suppliers. Prof. Craig Wheeler at University of Newcastle, Australia has a respected test facility that is based on his thesis work. He continues to update the procedures, as larger bearings are applied. Prof. Manfred Hager's (retired) work at Univ. of Hanover, Germany has performed many tests and has a respected test facility, based on the interests of Rheinbraun and major German system and component suppliers. FMC manufacturing in USA and China have a good testing and QA procedures. They attempt to be reasonably accurate. SME papers of the past which published measurements. Precismeca, manufacturing in Germany for Rheinbraun, et al.

Why do you wish to re-invent? It would be more helpful if you stated more specifically what you goal was with some details. What is your affiliation? Why didn't you complete the forum form on your details? We like to know who, what, why, ....... to encourage sharing and knowing who we are helping. This question has been asked before and answered by many before. ■

Item 5 refers to shaft deflection. Once the shaft rotation exceeds the bearing limiting criteria, the life will be reduced.

Also you should become familiar with ratings and failure criteria in order to properly assess the selection process. ■