Coil SumoSprings Custom Helper Springs for Coil Spring Suspension - Rear Axle
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1991 GMC Van
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1991 GMC Van
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Hauling gear, towing a trailer, or loading up for a trip can make your rear suspension work overtime. These Coil SumoSprings helper spring inserts slip between the coils of your existing springs to boost support and keep your ride level under load. Each spring has an inner core made from microcellular polyurethane foam that cushions the suspension and reduces harsh jolts when the weight piles on. The more you load onto your vehicle, the stiffer they become—so you get progressive support exactly when it’s needed.
Rear-end squat can throw off handling, steering, and braking when towing or carrying heavy cargo. The Coil SumoSprings helper springs increase your suspension’s ability to support weight, helping to keep things level and stable. The progressive design reacts to how much load you’re carrying, firming up as weight increases to cut down on body roll and sway without making the unloaded ride harsh.
Unlike air springs that rely on air pressure, tanks, or valves, these polyurethane inserts require no monitoring or upkeep. Just position them between the individual coils of your rear coil springs and you’re done—no hoses to route or fittings to install. Once in place they quietly go to work every time you hit a bump or add cargo, giving you consistent support with zero maintenance.
Road salt, oil, UV rays—these conditions can wear out lesser materials fast. Each Coil SumoSpring is crafted from durable microcellular polyurethane that resists abrasion and damage from heat or chemicals. They hold up through extreme temperatures and heavy use so you can depend on them season after season without worrying about leaks or breakdowns.
Installing this kit doesn’t require special tools or professional help. The wedge-shaped inserts are custom sized for a precise fit on rear coil spring suspensions that are already in good working order. Just lift the vehicle enough to extend the coils, slide the helper springs into place, and head back out on the road knowing your suspension has extra support ready for whatever load you throw at it.
Customer Satisfaction Score:
94% were satisfied with this product
6% of customers were not satisfied
Ratings & Reviews
These spring assists have resulted in a 2” difference in hitch height when my loaded single axle R-Pod travel trailer is attached. Very pleased. For the greater part of the year my trailer was not attached , I could not discern any difference in ride handling. However, I am no rally driver!
Just installed …takes about a minute per side once vehicle is raised.
Test drive was good and will road test today.
Very cool product.
2022 Toyota Platinum Highlander 10,000 miles.
Installed on 2022 Toyota Highlander XLE
Perfect fit, installation so easy, literally took me 5 mins per side, no tire removal just jacked up the vehicle and installed in place. Added a bit of ride height for pulling my trailer.
I tow a boat with my Highlander and this did the trick for helping the sag from the tongue weight. Minimal impact to the unloaded ride height which is a huge plus for me.
Product awesome but ordered set for my highlander and 2wd ones were sent questioned why they didn’t meet in middle was told I ordered wrong ones sent back ordered one for awd and still don’t wrap around the spring and look to be the same as first ones but $30 more
Kate F.
2/5/2026
I completely understand why this was frustrating, David. You’re right that the 2WD and AWD SumoSprings look almost the same. The difference isn’t in how they wrap the spring, but in their height and when they engage. AWD Highlanders sit slightly higher in the rear, so the AWD version is taller to work correctly under load, even though it may not meet in the middle of the coil. What are you hauling around that you needed the extra support?
The SumoSprings mounted securely and with ease. Some lubrication is helpful. These springs are a very unique way to manage a Coil springs response action. They literally will provide a calmer and smooth riding experience. That is, they reduce overreacting of each coil. I do recommend the SumoSprings.
Took a chance and ordered rears for my 2021 AWD Pacifica even though the AWD model wasn't listed. After cutting a couple of inches off they fit perfectly! Coils are tight so you'll need to unbolt the bottom shock bolt to gain an extra inch of decompression. Once installed there's no difference in ride hight or ride with the van unloaded. Once loaded up it gives the extra support needed to prevent scraping my muffler pulling in and out of driveways. I know this mod voids the warranty, but it was a chance worth taking.
I installed the Sumo Springs in my 2016 Toyota Highlanderthey fit well. Total install took approximately 10 minutes.
2021 Highlander front with drive V6. Product is right on the money for description. My Bass boat is 3900lbs, definitely took a 1-1/4 out from the sag. Also, extremely less bounce. I would prefer to have air bags, though no one makes them for my year. This is a great alternative.
So far so good. I have not pulled my basecamp 20x trailer yet. But I expect positive results on sway reduction
I installed the springs myself. I did not have a floor jack. Cannot use the tire jack. I used 2 (4) ton bottle jacks and 2 (3) ton jack stands. My set up time was about 2 Hrs. The first spring took about 30 mins to install. Once I figure what I was doing wrong the second one took 5 mins. With a floor jack this is a 15 min job.
Had trouble installing them at first
Finally found a method to in stall one end forcing the back lip in with a screw drive ,rotating the unit slightly then force the next section over the coil spring
It lifted the back end by one inch and does not drop the back end as much loaded
Lodwik
9/25/2025
After 12 months is works great to lift the backend of 34 ft rv when parking And more stable when driving
They are easy to install; back end comes up about inch. the ride is a little firmer, but I like it.
Everything works great! I love products.
Here's a shot of the Sumo Springs installed on my 2005 Prius:
Justin G.
1/8/2015
They are great! Big difference from stock.
Good product - so far, doing the job it was designed to do!
These coil helper springs are expensive for what they are, but wow did they make a difference on the rear of my 2019 Toyota Highlander XLE AWD! Rear squat is basically eliminated when I have our two heavy ebikes on the Kuat hitch rack or when our camper with 375 LBS of tongue weight is hooked up. During towing the rear end feels stiffer and more stable with the coil helpers. Under normal driving conditions, especially on the curvy mountain roads, body roll is greatly reduced. These were easy to install, especially with the wheel removed to get better access. I ended up drilling a small hole through the middle of each end and zip tying them to the coil spring. They are expensive and I don’t want to loose them if they happen to pop out. Usual excellent information, videos and fast shipping from etrailer.com.
Installation was easy and I felt the difference immediately when I started to drive. I haven’t put a load on it yet so that will be the real confirmation but for now I gotta say I’m pretty impressed with the quality and simplicity of the installation and the product.
Fast shipping!!!!
Very impressed with the SumoSprings. Was hesitant at first, but purchased a set for my 2017 Hyundai Santa Fe limited ultimate that had a squishy feeling ride and looked like it sat a bit lower in the back. Installed these on the rear springs and raised the ride height 1" in the rear and the ride is much better already. I'll have to see how they do with a loaded down vehicle but without the SumoSprings, 2 adult rear passengers and 2 dogs in the very back, suspension bottomed out over decent bumps and was not a good experience at all!
They have not affected the ride as I can tell, ho0wever, I have not towed my trailer as yet. we will see. They were super simple to install. No soap needed.
Great product, easy install. Solved the trailer squatting problem
Worked very well. Easy to still after I figured out installation.
Sumo Springs helped a lot with rear sag on the Highlander when hauling heavy trailer loads. No negative effect on front end handling. So far.. so good! Will see how pulling at 7x14x14 tandem axel trailer will do next.
I recently installed these along with new Monroe struts on my 2010 Toyota Highlander. What a game changer. We tow a Rockwood Freedom 1910. While the Highlander has plenty of power and decent towing capacity, I was unhappy about how the vehicle rode and sagged when towing the camper. Those days are long gone. The Sumo Spring raised the ride height about an inch overall and it doesn’t sag much at all when towing. The ride is a little stiffer but the Highlander handles so much better. No body roll when cornering and not a lot of forward pitch under braking. These Sumo Springs Sumo Springs are worth every penny.
As mentioned in previous reviews, these SumoSprings Helper Springs resolved the known 2025 Toyota Highlander Hybrid sag issue when there is any weight on the hitch or in the back of the vehicle. It completely eliminated it on my 2025 Highlander. Installation was extremely easy (less than 10 minutes) after watching the Etrailer and SumoSprings installation videos (you really only need to watch one of them as they are almost identical). I highly recommend these SumoSprings Helper Springs if you have any issue with sagging on your Highlander.
Took about an hour to install because I had normal jack and wanted to take tire off for easier access to spring. Once I had the tire off it literally took 1 minute to feed the support on. I did use warm soapy water as one video suggested. Looks like it raised the rear about an inch and looking forward to less sag in the ride with 20 ft travel trailer attached.
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Scott
7/7/2025
Still glad I have used these springs over the past year of towing. I could almost use a set that is just a little bit stiffer but still way better towing with them for sure!