Polymer Wear Rings

The primary purpose of a wear ring is to guide the piston and rod of a hydraulic or pneumatic cylinder while absorbing side loads. By preventing metal-to-metal contact between moving parts (like the piston and the cylinder bore), wear rings eliminate galling and significantly extend the lifespan of the seals and the equipment itself.

Wear rings are manufactured from high-performance materials designed for low friction and high compressive strength. Common choices include:

• PTFE with fillers: Bronze, carbon, or glass-filled PTFE offers excellent low-friction properties.
• Metals: Greased metal wear rings can be made from bronze, stainless steel, or cast iron depending on the needs of the application.
• Dry-running plastics: igus’ own dry-running plastic materials offer low-friction performance without the need for additional lubrication.

Wear rings are almost always manufactured with a gap (butt cut, angle cut, or step cut). This is not a defect; it serves two purposes:

• Thermal Expansion: It allows the material to expand as the system heats up without seizing.
• Installation: It allows the ring to be snapped into closed grooves more easily.

If you’re using an iglide wear ring, the service life is predictable with a high level of accuracy, letting you know ahead of time exactly when replacement is needed. For non-iglide wear rings, signs like increased wear, decreased ring thickness, or leaks all point towards needing a replacement.

No. Wear rings are not sealing elements; they are guiding elements. While they may slightly restrict fluid bypass, they do not have the flexible "lip" required to create a pressure-tight seal. They should be used in conjunction with a dedicated piston or rod seal for adequate sealing.

Absolutely. By keeping the rod or piston perfectly centered, wear rings ensure that the seals maintain even lip pressure. Without a functional wear ring, side loading causes the seal to compress more on one side than the other, leading to premature damage and leaks.