Series 5 Cylinders: Strength, Reliability, and Greater Payloads

November 24, 2025

Grant Bowyer – Product and Applications Engineer

Our cylinders have long been recognized as some of the most versatile in the industry, providing users with greater payload capacity. Yet, we consistently strive for improvement.

Interpump Hydraulics, our sister company, has enhanced its telescopic single-acting cylinders to boost performance. New phenolic resin sliders, upgraded pin eyes, and new direct mount tipper valve capabilities represent significant advancements to both Pin-pin and Trunnion Mount Cylinders.

PHENOLIC RESIN SLIDERS AND STAGE OVERLAP

Many of the improvements are not easily visible when looking at the cylinders. Both the Trunnion Mount and Pin-pin Cylinders now use phenolic resin sliders, rather than Delrin sliders. Phenolic resin sliders are known as one of the strongest sliders on the market.

On the right of the image, there is a transparent Trunnion Mount Cylinder next to a non-transparent Trunnion Mount Cylinder with a line and circle highlighting the location of the phenolic resin sliders. To the left the image, there is a transparent Pin-pin Cylinder and a non-transparent Pin-pin Cylinder highlighting the location of the phenolic resin sliders with a line and circle.

Alongside increased overlap between stages, these sliders contribute toward superior strength when encountering loads and side load absorption.

WIPERS (SEALS)

With the addition of new phenolic resin sliders, the wipers (seals) in both cylinders now feature a redesigned double lip.

The image shows a diagram of the double lip wiper that can be found in both the Trunnion Mount and Pin-pin Cylinders.

This upgrade helps keep moisture out of the cylinders and prevents oil leaks, making Trunnion Mount and Pin-pin Series 5 Cylinders nearly waterproof and highly resistant to extreme temperatures. As a result, they provide reliable performance, even under harsh weather conditions.

BOTTOM PIN AND PIN EYE CHANGES

The Pin-pin Cylinder saw a specific change: the design of the pins.

The bottom pin, which mounts the cylinder to the base, was increased from a 2" diameter to a 2.07" diameter to allow optimal tolerance when manufacturing the cylinder’s pin eye, which leads to a more consistent clearance on upfit.

The image shows a transparent Pin-pin Cylinder with spherical top pin eye highlighted in green. Next to the transparent cylinder, is a non-transparent Pin-pin Cylinder with a circle and line highlighting the location of the top pin eye.

Additionally, the top pin eye was completely redesigned with your worksite needs in mind. It now includes a spherical bearing that allows a small third axis of movement while keeping the dump body stable in the process and improving side load absorption.

DIRECT MOUNT TIPPER VALVE

Along with these improvements in the Pin-pin Cylinder comes the ability to directly mount the DS16 Series tipper valve to the oil port.

The image shows the DS16 Series tipper valve to the left. To the right of the image is a diagram of how the DS16 Series tipper valve mounts directly to the Pin-pin Cylinder with a circle and line highlighting the tipper valve.

This not only saves space and your time when deciding where to mount the tipper valve, but it also reduces system complexity by eliminating the hose and fittings that would traditionally snake from the valve to the cylinder body.

CUSHIONED RETRACTIONS

Finally, for the Pin-pin Cylinder, there is now cushioning provided during retraction due to the updated porting.

The image shows the diagram of the Pin-pin Cylinder porting diagram.

The inlet port has two holes forked under the main port on the base tube, which helps reduce oil flow as the first stage retracts to its resting position.

Inside the cylinder, as the first stage’s bottom sliders pass over the holes, the oil flow alternates between both holes. This reduces the risk of damage on retraction and extends the lifespan of the system.

Both the Trunnion Mount and Pin-pin Series 5 Cylinders offer high maximum pressure to allow for less expenditures elsewhere. Engineered for versatility, they’re suitable for small dump trucks to large dump trailers.