Rollico
In many designs, the bearing cage is treated as a secondary component—selected “by size” without a deeper review of operating conditions.
In practice, however, it frequently defines:
If your application requires high precision and predictable lifetime, selecting a cage “by feel” is not an option.
Before you decide, review these 6 key parameters.
The first question is not “what size?”, but what is the actual load acting on the cage?
Has it been converted to the load per individual rolling element?
Dynamic and static load ratings are the foundation of durability—these are not values to estimate.
How to calculate:
Cage load capacity = number of rolling elements × load capacity of a single rolling element.
Skipping this step increases the risk of accelerated wear, loss of accuracy, or premature failure of the entire mechanism.
What level of motion accuracy does your application require?
The rolling element type directly affects system behaviour:
Ball cages (RKK, RRK)
Roller cages (RBN, SRN)
This is not a matter of preference.
Selection depends on the application and the linear guide type.
At first glance, parts may look similar.
Example:
RRK6 and RBN6 use the same shaft diameter (6 mm), but have different cage designs—matched to the groove and raceway geometry of the linear guide.
A mismatch means:
→ no assembly possible.
Always evaluate the cage as part of the complete linear guidance system—not as a standalone component.
Details matter here:
Important note:
When ordering 500 mm, the standard supply may be shorter by up to one pitch.
If your design requires a defined effective length, account for this already at the specification stage.
Even a correctly selected cage may underperform if operating conditions are not considered.
Ask yourself:
Mistakes here often only become visible during operation—when corrective actions are significantly more expensive.
Not every cage fits every duty.
Selection should follow the functional requirements of the system—not only part availability.
If your application requires:
→ the cage stops being a “detail”.
It becomes the component that determines overall motion quality.
If you’re not sure which type to choose—contact Rollico’s expert team.
Sometimes one correct selection at the design stage prevents years of operational issues.