X Ring vs. O Ring: How to Choose The Correct One

21 March 2019
Choosing the right seal is not a simple matter. You have many factors to consider in terms of the seal’s application, and you also have many options. X ring vs. O ring is perhaps the first question to ask. In some applications, either type of seal will work. In others, one type will work much better. The trick is to understand the various factors that influence which type of ring seal will be the most efficient and most durable in the specific application.

What distinguishes an X ring vs. O ring is actually not the shape of the overall seal. That circular shape is why it is called a ring. The X or O is for how it looks if cut into a cross section. While an O ring has a smooth, convex surface, an X ring has four grooves. That amounts to two sealing surfaces per side for the X ring vs. just one for the O ring.

Strengths of the X Ring vs. O Ring

One of the most critical differences between the two rings is how they cope with a dynamic application. In an application with moving parts, the ring endures repetitive impact. An O ring will become compressed in this situation, potentially compromising the seal. How exactly an O ring reacts depends primarily on the material it is made of, but environmental factors such as moisture and temperature also influence how the O ring responds and durable it is in the specific application. An X ring is better designed for dynamic applications as the shape accommodates repetitive impact.

Another reason to choose an X ring for a dynamic application is that their structure prevents spiral twisting. The four ends of the X shape provide a stability that an O ring cannot offer.  An O ring is perfectly adequate for some low-speed pivoting, rotating or spiralling movement, but an X ring can better accommodate faster motion. An O ring might do the job for a short period, but an X ring will be more durable in applications with rapidly moving parts.

In a static application, an O ring can offer advantages over an X ring. They are easier to install and their simple design makes them preferable for smaller spaces. In wet applications, such as equipment used underwater, an O ring is ideal.

The choice of X ring vs. O ring depends entirely on the specific application, right down to the details of how rapid movement is and how wet or dry the environment is. Knowing the challenges of a particular application is the key to making the right choice between X ring vs. O ring.

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