So many times we have been asked this question about bearing clearances that we thought it would be informative enough to post. We relied on our friends at Callies Performance for their opinion. As it turns out, there is no exact answer but rather a range depending on the user.

Using this chart graph, there are 3 major considerations Clearance vs. Oil Flow Rate, Clearance vs. Bearing Temperature Rise and Clearance vs. Load Capacity. Just as with everything else in life, there are trade-offs. As you can see from the attached chart, most likely the decision a Competition Eliminator racer would make would be different from the decision a performance street racer would make.

The question most often is asked as it applies to coated bearings. Dry film coatings used on engine bearings is typically 0.0002" to 0.0004" thick and generally speaking does not need extra clearances. A benefit of coated bearings is the allowance for tighter clearances, keeping in mind that bearing clearances of .002" to .003" are typical for High Performance applications.