Many bearing manufacturers have a product they would consider “free spinning”. There are several ways to accomplish “free spinning”. Some common ways are: using a low viscosity grease or oil; running them dry; using a low drag non-contact seal; running them open; using a nylon cage. Each of these methods can realize some degree of “free spinning” as compared to regular lubricated and sealed product. Each method, however, also has a down side to its use. For example: running dry dramatically shortens bearing life; running open offers no protection against contaminants; nylon cages will limit useful application temperatures; low viscosity grease or oil lubricates poorly at high temperatures; etc.
CSL lubricated bearings will spin much more freely over a longer period of time without the downsides commonly associated with the above methods. In fact, CSL lubricated bearings with spin free regardless of operating temperature within the -150°F to +660°F range. (Note: 660°F is a continuous rating, CSL660 has a practical limit of +1200°F with very slow degradation over time.)
But why should you care about free spinning? Lots of answers to this question! Some answers are universal to all application (like reduced energy consumption and reduced ware on associated gears boxes) while other answers are application specific (like stretch in plastic, alignment in printed product, wide temperature variations in the same application, paper converting, etc.).
The video below is a demonstration comparing the free spinning, low-torque nature of CSL products vs. a typical low-torque, metal shielded ball bearing. Both of these aluminum wheels are fitted with 6204 bearings. The wheel closer to the vice grip on the shaft houses a CSL processed bearing & the wheel at the far end of the shaft has a standard low-drag bearing with metal shields. An approximate 10 seconds blast of air is applied to both wheels to get them going. You will see that both start off spinning really fast and well, however you’ll come to notice that the wheel without the CSL processed bearing begins to slow down much sooner than the bearing processed with CSL. A few more blast of air are applied to the non-CSL wheel, all the while the wheel fitted with a CSL processed bearing continues to spins on its own at a smooth rate without any additional blasts of air.