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Sulastic Rubber Leaf-Spring Shackles Update

Taking a close look at durable rubber suspension parts after 5 years of daily, hard use.

Jun 5, 2020
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For this report, we're taking a trip back in time to 2015, when we installed Sulastic Rubber Springs' leaf-spring shackle kit on our 1995 Ford F-350. At that time, the shackles were selected as part of an effort to improve "Big White's" ride quality and enhance handling when towing.
While San Antonio, Texas-based, American Sulastic, Corp produces rubber pulleys, casters, body mounts and bushings for the automotive, truck/bus and industrial sectors, Sulastic suspension pieces—specifically rubber leaf-spring shackles for lifted, lowered, and stock ride-height trucks and vans—are the parts the company is best known for producing.
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In contrast to stock, fixed, stamped-steel shackles, the Sulastic hangers are multi-part pieces highlighted by large rubber bushings that act as fulcrums and enable leaf springs to "give," "comply," or "flex" in an up-and-down fashion, with road-surface variations and objects trucks drive over.
With the anniversary of our leaf-spring-shackle (per the box, they're Rubber Leaf Spring Shocks) installation here, we thought it would be cool to actually go and take a look at the setup beneath Big White's bed.
Five years later, the shackles are still working perfectly. While the truck's ride quality continues to be a work in progress, and it's far from being as comfortable and soft/smooth as that of a brand-new rig, Sulastic's brackets continue to prove themselves to be great additions on our OBS Ford dually. The truck is driven daily, and it tows and hauls on a regular basis. Our inspection found zero faults, and we're confident things will probably look the same when we revisit this in 2025.
The following photos and video highlight the truck's original leaf-spring hangars and the Sulastic rubber shackles then and now. If you're looking for a budget-conscious method of bringing better ride quality to your truck—old or new—they're worth looking into. We understand they also calm the "bed bounce" that some late-model trucks experience at freeway speed, particularly without a load.
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American Sulastic Corp


American Sulastic Corp