One of the most common questions when choosing ball bearings is whether to select a 2RS sealed bearing or a ZZ dust cover bearing. Both types of bearings belong to the deep groove ball bearing family, but they are designed for different operating conditions. Understanding their differences will help you choose the best option for your equipment, thereby improving bearing performance and lifespan.

What do 2RS and ZZ stand for?

ZZ type seals are non-contact seals and are the most common type of bearing seal on conveyor rollers. Compared to 2RS type contact seals, this non-contact seal generates significantly less friction (or even no friction) and heat. However, non-contact seals also have the problem of lubricant leakage; lubricant may leak from the bearing cavity, and some tiny contaminants may also enter the bearing cavity. External seals are crucial for maintaining the integrity of the lubricant, thereby extending the bearing’s lifespan.

2RS refers to a contact seal on both sides of the bearing, which is required for some applications of conveyor rollers. These seals utilize elastic materials to apply continuous pressure to the surface, forming an effective sealing interface. This sealing method effectively prevents fluid or solid particles from seeping into the sealing area, but direct contact with the bearing inner ring generates additional friction and heat. Therefore, this additional friction and heat must be considered when selecting a contact seal solution. This additional friction increases the starting resistance and flange resistance of the conveyor rollers, thus affecting the conveyor’s start-up and operating power requirements.
Both sealing methods have their advantages, the choice depends on your operating environment.

Which is better, 2RS or ZZ bearings?

Advantages of 2RS Bearings
2RS bearings use contact seals, meaning they effectively prevent the intrusion of dust, dirt, and moisture. Therefore, they are ideal for:
Outdoor equipment
Agricultural machinery
Conveyors and industrial machinery operating in dusty or humid environments
Automotive applications, such as wheel hubs or alternators
Key benefits of 2RS bearings:
Excellent sealing performance and contamination resistance
Pre-lubricated and generally maintenance-free (“lifetime seal”)
Extended bearing life in harsh environments
However, rubber contact seals increase friction slightly, which may slightly reduce the bearing’s maximum speed and increase operating temperature.
Advantages of ZZ Bearings
ZZ bearings feature a shielded design; the metal cap provides moderate protection and eliminates contact friction. These bearings are commonly used in high-cleanliness, high-speed applications, such as:
Electric motors
Power tools
Fans and water pumps
Industrial machinery operating in clean environments
Key advantages of ZZ bearings:
Reduced friction and heat generation
Higher speed capability
Cost-effective choice for clean environments
Some dust and debris protection
Disadvantages: ZZ bearings are not completely sealed, so fine dust or moisture can still enter, which may shorten bearing life in harsh environments.

Which bearing is better?

There is no single answer—it depends on the specific application.
If your equipment operates in a dirty, humid, or outdoor environment, or if you prefer low maintenance and maximum protection, choose 2RS bearings.
If your machinery operates in a clean environment and requires higher speeds and lower friction, choose ZZ bearings.
In short:
2RS = Better Protection
ZZ = Higher Speed

DFL NSAR provides a reliable bearing supply

As a professional bearing manufacturer and supplier, DFL NSAR offers 2RS sealed bearings and ZZ shielded bearings for a wide range of applications. With advanced production lines, rigorous quality control, and overseas warehouses located in the United States, we are able to provide global customers with fast delivery, OEM customization, and highly competitive prices.
Whether you need deep groove ball bearings, mounted bearings, or rod end bearings, our engineering team can help you choose the best sealing solution for your equipment.
Contact DFL NSAR today to learn more about our 2RS and ZZ bearing ranges or request a free quote.