Q4. What's The Difference Between Bearing Seals And Shields?

 Seals and shields are both in place to keep contaminants out of a bearing. In order of effectiveness, the enclosures that are offered are as follows: metal shields, rubber non-contact seals, Teflon non-contact seals, and rubber contact seals. Not surprisingly, as the sealing performance is increased, the torque required to turn the bearing will also increase due to the increased friction caused by the seal/shield. The application's condition and life requirements are important to know to determine the best shield or seal choice.

Consult with one of AST's sales or engineering personnel to help determine what is best for your particular application. 

Also, you can read AST's white paper on this subject for an indepth discussion on closures entitled, "Ball and Roller Bearing Closures"