Sealed bearings | Bearing closures | Bearing design | SMB BearingsChoosing a bearing can feel like a complicated procedure, but it doesn’t have to be with the right expert advice. Design decisions extend far beyond a bearing’s material choice and dimensions. So, where do you start in specifying your requirements for bearing shields and seals? With the SMB shields and seals guide of course.

Sealed vs open bearings

Many bearings, such as cartridge bearings, are available with different types of shields and seals, commonly referred to as bearing closures. These closures are not always essential; however shielded and sealed bearings provide much better protection from contamination and help retain the bearing lubricant over the bearings’ lifespan.

This guide provides a technical introduction to the options available, covering the three main categories: the metal shield and the two types of ball bearing seals:

  • Circlip removable shield and pressed non-removable shield (bearing ZZ type)
  • Contact seal (bearing 2RS type)
  • Non-contact seal (bearing 2RU type)

Picking between these options is largely dependent on your desired application and environment. This guide explains the key characteristics for each of these closure options, the lubrication options and application advice.

Download the guide here, to determine which bearing closure is right for you.

Asking the right questions

There are three important application focused questions that you need to bear in mind when choosing between seals and shields. It’s a bit of a balancing act between the level of contamination protection you require, bearing operating speed and temperature range. For each of the following questions, we provide a closure suggestion that will best suit the environmental conditions.

  • Do you require high contamination protection?
  • Will the bearing be operating in extreme temperatures?
  • What speed will the bearing be operating at?

Shields and seals guide FAQs:

In this guide, we have collated the extensive knowledge of the SMB Bearings technical team and we’ve even thrown in a handy shields and seals property comparison table. But, if you still want further information, we also answer the most commonly asked questions related to shields and seals and their potential applications.


Click here to download your essential guide to shields and seals.

Alternatively, to speak to a bearing specialist, contact the SMB Bearings team directly on +44 (0) 1993 842 555 or e-mail

Our determination to remain specialised gives us a high level of product knowledge, providing bearing and lubrication solutions to existing or potential customers, whether individuals or large corporations. We don’t just sell bearings, we help to solve your problems. - Chris Johnson, managing director of SMB Bearings.