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Heavy loads can make the rear end sag, which throws off steering and braking. These SumoSprings Solo helper springs add up to 1,400 lbs of support at 50-percent compression to help your suspension stay level and stable when towing or hauling. They absorb bumps and shocks so handling stays smooth and your ride height stays even.
These microcellular urethane springs compress progressively depending on how much weight you’re carrying. With lighter loads, they compress easily for a soft, comfortable ride. With heavier loads, they can compress by as much as 80 percent to give firm support and help prevent bottoming out. The result is a balanced ride that stays comfortable when empty and stable when loaded.
Each spring works on its own side of the vehicle, compensating for off-center loads and reducing body roll during sharp turns. That means more control when you’re cornering or driving in crosswinds. Whether you’re running uneven gear in the back or towing on a winding road, your vehicle feels planted and predictable.
The closed-cell microcellular urethane stands up to oils, road salts, and UV rays, performing from -25?°F to 200?°F. The springs compress vertically with minimal lateral expansion so they resist damage in tight spaces. They also require no air pressure checks or tubing—just install them once and drive knowing they’ll keep working trip after trip.
These helper springs are custom-fit and bolt on with simple hand tools—no drilling needed. Each kit includes two jounce-style springs that replace the factory bump stops to enhance load carrying ability, reduce sway, and improve ride comfort without changing your normal suspension setup.
Customer Satisfaction Score:
95% were satisfied with this product
5% of customers were not satisfied
Ratings & Reviews
Fairly easy to install on GX 460 and does not change the unloaded ride quality. I installed without jacking it up or taking off the tire, but it was cramped space.
Can’t beat the Sumo Spring fir the price! Stabilized my 4 Runner body roll and kept it from sagging when towing my boat. In my opinion, these are a no brainer.
I put them on an overland rig pulling an off-road trailer. Shoulda done it sooner. Big plus!
I enjoy the Solo helper springs a lot. I dont get the sag on my 4 runner when towing my boat.
This worked perfectly for what I needed my 4Runner no longer sags with the trailer and without the trailer it actually corners tighter with less sway and ride smoother.
And this directly mounted in the exact bump stop location with the same mounting hardware in fact they sent hardware I guess so it fit on other vehicles but it was a direct replacement of The bump stop on my 2010 4Runner
Install was not hard (unless your stuff is rusted…)
Springs are a bit more on the rough side of driving, smooth but rough. Lots of bounce on the car, but having it fully loaded +18 hour drive, these springs did NOT give up.
My FJ Cruiser needed a pick me up when hauling my 16' camper.These overload springs have done the trick, keeps things level.Thanks for a quality product.
I just returned from my first trip since installing the Sumo Springs on my 2022 Toyota 4 Runner and the improvement while towing my 3200 lb travel trailer was amazing. The squat was non existent and the overall handling felt more confident. The installation was easy, but I do recommend removing the wheel. This was a simple fix that works!
These make all the difference towing a camper with my 4Runner. The rear sagged badly prior to installing sumo springs. Excellent investment. I was able to install them without removing the wheels, but the limited workspace made it challenging. Would be a piece of cake with the wheels off.
These sumo springs work great on my 2016 Toyota 4Runner. When towing a 3.5k lbs load, the rear sag was significant and negatively impacted the handling. Now with these Sumo springs the rear sags only about 1" when the trailer is hooked up.
Better overall ride quality than the Timbren rubber springs I originally had installed. The Timbren are excellent for heavy loads and I may hang on to them for that reason. The Sumosprings were even easier to install than the Timbrens, so I'd recommend the Sumosprings over the Timbrens based on ease of install as well. It would make it easy should you find yourself needing to switch back and forth. It'll take you 20 minutes at the most to change both sides. This includs getting out the tools, jack, jack stands, wheel chocks,and putting everything away when done. Time is about the same with or without removing the wheels.
My GX460 is self leveling, but it doesn't hurt to give the suspension a little help towards longevity (Air bag repair can be pricey on the GX). Picture shows the limited work space with the tire on the vehicle while on the ground. Please note that with the vehicle raised there's a lot more room to work and access from the bottom as well. I didn't find the need to work from underneath the truck.
Easy install. Made ALL the difference while towing out pop up camper with our 4Runner.
Great service. Shipped quickly and arrived 3 days ahead of when the tracking said they would be here. Very very happy with E-Trailer.
I gave the SumoSprings an initial rating of 4-stars because they do work as advertised. During the first thousand miles I've driven since installing them on my 2019 Toyota 4Runner, I have noticed they contact the rear axle much sooner than the OEM bumper stops which serves to quickly increase the suspension's resistance to any further downward motion of the truck's body - which not only dampens excessive rear end "dipping" on rough terrain, but also works well to prevent any appreciable rear end squatting from the tongue weight of my heavy 2-axle utility trailer.
I reduced my initial rating by one star because, while they centered on the mounting bracket holes in the same manner as the OEM bumper, I wasn't able to center the SumoSprings over the rear axle even after pushing them as far forward as the elongated bolt holes would allow.
Since the center of the SumoSpring pad (midway in the adjustment range of the elongated bolt holes) is in exact vertical alignment as the center of the OEM bumper, the only explanation would be that the 4Runner's coil-spring rear suspension has a slightly arced rear-axle "full travel" range as it rises upward from the lowest to highest position. If that "full travel arc" moves the axle to its rearmost position when the suspension is at full compression (where it contacts the OEM bumper), the "full travel arc" would then move the axle about 1/2" forward during the downward portion of the arc back to the normal ride position.
Therefore, since the surface of SumoSpring's long cushion pad is very close to the axle when it's in the normal ride position, that would explain why the SumoSpring at its farthest forward adjustment position is still about 1/4" to the rear of being centered on the axle(even though the SumoSpring in that position is now a bit further forward from vertical center of the OEM bumper).
However, since the rear axle's upward travel moves it slightly to the rear (and more toward center-mass of the SumoSpring's cushion pad), perhaps it won't suffer any premature deterioration or failure - but only time will tell about the SumoSpring's durability and longevity.
Brent
10/22/2022
After 70,000+ miles of both highway and off-road driving with and without a trailer in tow, I am upgrading my original rating to 5-stars because the bluemedium SumoSprings have performed exactly as advertised and show no signs of degradation in either wear, appearance, structural integrity or any noticeable deformation after being hammered unmercifully by the tongue-weight of the trailer I frequently tow along with the “moonscape” off-road terrain and even worse conditions of the roads I usually travel . Even though the SumoSprings still lacked ¼” from being perfectly centered on my 2019 4-Runner’s rear axle housing after installing them as far forward as their elongated slots would allow, my assessment of the suspension’s compression arc moving the third-member a bit to the rear on its upward swing proved to be true since the “shiny spots” of the contact points on the rear axle housing are well-centered. Unlike a Jeep Wrangler with an extremely stiff “hay-wagon” ride and having “no butt” or cargo space that protrudes more than a few inches past its rear wheels to strike the ground after traversing a sharp terrain -off, the largerlonger 4-Runner with a more comfortable ride has a lot of rear body protruding past its rear wheels – especially with a trailer hitch draw-bar attached. The 4-Runner’s hard-rubber OEM bumper stops allowed almost 5-inches of upward rear suspension travel before “bottoming out” which occasionally caused the underhung spare tire or hitch drawbar to contact the ground in extreme off-road terrain -offs or sudden roadway dips when towing a loaded trailer. However, the SumoSprings worked magic because there was only ½” clearance between them and the rear axle housing under normal conditions, and the rear axle housing gently touched the SumoSprings when the trailer was hooked up – which almost completely eliminated rear-end squat on a sharp off-road -off or sudden roadway dip without making the 4-Runner ride like a hay-wagon, farm tractor, 1950 International pickup with overload springs, Jeep Wrangler, etc. in the process. After another 250,000 miles or so, I’ll put SumoSprings on my next 4-Runner – good show guys!!!
After 1 yrs of having these, I'm still amazed how such a small upgrade made the 4Runner ride and handle.
Measuring before and after w fuel and trailer.. before was ablut 2 1/2" sag. After the install it was right at about 1 1/4" sag.
Along with helping with sag, it also eliminated a significant amount of roll in corners.
Great upgrade!
Have suggested these to a few friends.
Very impressed.
Way faster delivery than I expected. The Sumo Springs are great
Russ
3/16/2025
The Sumo Springs have worked perfect, the motorhome has near zero sway and roll. When the similar goes past it doesn’t move. I heard Tiffin gas motorhomes that are new offer them as an option.
Kate F.
3/16/2025
The parts are made with what appears to be a powder coat paint job.They all came packaged nicely and well protected. The instructions are clear, accurate and easy to follow. Mentioning that there is a left and a right assembly may be helpful to some. Mentioning "outboard" may be ovelooked by some. They installed easily. Removing the wheel gives you plenty of room for easy access. Once installed with my 4runner on the ground, the SumoSprings were resting on the frame. I do have a dog kennel and lots of training equipment that is loaded constantly. Hopefully these will help when I pull my RV. I did take it for a drive and it felt "firmer" more stable around sharp curves. I like them.
This review is based purely on the installation. It took as long to jack up my 4Runner, place jack stands under the frame, and remove the tires as it did to install the Sumo Springs. I installed these to lessen the squat of the 4R while towing my boat and my camper (WD hitch used while towing the camper). The Sumo Springs sit just above the real axel which should greatly reduce the squat and lessen the bounce while towing. Went this route based on other 4Runner owner's reviews.
This stuff is up the ride but it actually makes it nicer if you throw something on the hitch easier to control this is my third set I put on my vehicles and worth 100%
The Suma springs are a great product. I have used them on my travel trailer for several years. They have performed well and the RV has better stability. Unfortunately I am returning this product because I no longer own the tow vehicle they were purchased for. etrailer has a great return process making this less stressful.
Bumpy ride with no load, I have a 22 4runner and I thought these were not supposed to contact my axle unless I had a load on my hitch, towing was great, but with them installed you feel every bump when nothing is in tow. Not a great solution.
Picked up the slack my 23 4Runner had in the rear end when towing my camper. A must have if you want to keep your comfortable SUV ride but also be able to tow something on the heavy side.
Quality is fantastic. Exactly what we n eeded
Fast shipping and super easy install on Gen5 4Runner. No noticeable degredation in ride quality while unloaded. With trailer attached, much less sag, nice, well controlled ride. Great purchase.
The order came on time. The install was easy and looks good. I haven't got to put them to the test yet with a trailer hitched up. Regular driving is good. So I will only give 4 stars at this point.
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Jenny N.
10/27/2021
Thank you for the detailed feedback. When the SumoSpring is installed you will want to position the bracket so that it is offset outboard towards the wheel. This product does have a limited lifetime warranty against defects.