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When your suspension starts to sag from extra weight, harsh bumps can wear you down fast. Coil SumoSprings slip between your existing coils and use a microcellular polyurethane foam core to add cushioning and support. The material compresses progressively as your load increases, giving you a smoother ride when light and firming up automatically as the weight comes on. It’s extra comfort that keeps long hours behind the wheel from feeling rough.
Extra front or rear weight can throw off balance and steering. These helper spring inserts work with your factory coils to help level your vehicle under heavy front loads like snowplows or rear loads from towing and cargo carriers. The more weight you add, the stiffer they become—helping keep your suspension steady without needing any air pressure adjustments or monitoring.
Upgrading suspension shouldn’t mean adding more parts to check or service. Unlike air springs, Coil SumoSprings don’t rely on air systems at all. There are no lines to route or fittings to leak—just a solid, maintenance-free insert that fits between the coil loops. Once installed, they quietly do their job every time you hit the road with a load behind you.
From hot asphalt to winter salt, suspension components take a beating. These helper springs are built to resist abrasion, oil, road salt, and UV damage so they keep performing season after season. They withstand extreme temperatures without breaking down or losing shape, giving you reliable support no matter where you drive.
Adding load support doesn’t have to be complicated. Each set includes two helper springs designed to install easily on front or rear coil suspensions in good working order. They fit between individual coil loops with H-shaped channels that hold securely in place—no special tools or adjustments required. Just slide them in and get back on the road with a ride that feels more stable and controlled.
Customer Satisfaction Score:
91% were satisfied with this product
9% of customers were not satisfied
Ratings & Reviews
Carl
11/7/2022
My experience with these are still good. I did notice that one side had rolled off the coil despite having the zipties still in place, but they still work as well as I could have expected. I still experience some sag while towing a trailer, but it is not as bad as if I did not have these installed. This vehicle seems to be very sensitive to tongue weight even when the trailer is empty
Lazer S.
3/24/2026
Sorry to hear about the install difficulties, Robert. I do have to say that this kind of suspension supplementation will never lift the vehicle they are installed on though. They will really only "tighten" up the compression of the coil springs to offer more support. Have you tried towing anything with your Promaster yet to see if there is any difference? They do have a 30-Day satisfaction guarantee in case they don't perform to your liking.
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Bruno F.
1/28/2020
So far so good it eliminates sag while towing or having heavier objects in the vehicle.