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SumoSprings Trailer Helper Springs w/ Line Relocation Bracket - Single Axle - 3K to 5K - Overslung

SumoSprings Trailer Helper Springs w/ Line Relocation Bracket - Single Axle - 3K to 5K - Overslung

Item # TSS-107-40
Our Price: $249.99
You Save: $59.37
Trailer Leaf Spring Suspension
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Shipping Weight: 6 lbs
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Product Expert Kathleen M

Is this right for you? Product Expert Kathleen M says:

Yes, if you:

  • Find yourself swaying and rolling when going over driveways or areas with gusting winds
  • Have limited tools and/or experience with making modifications to your trailer
  • Have an overslung axle, which means the leaf springs sit on top of it

No, if you:

  • Have issues with your wheels bouncing after hitting bumps and need something to control that rebound
Improves suspension, handling and safety. Progressive spring rate. Provides additional support as needed so you always have a smooth, comfortable ride. Lowest Prices for the best trailer leaf spring suspension from SuperSprings Intl. SumoSprings Trailer Helper Springs w/ Line Relocation Bracket - Single Axle - 3K to 5K - Overslung part number TSS-107-40 can be ordered online at or call 1-636-306-4830 for expert service.
  • All Info
  • Reviews (58)
  • Q & A (0)
  • Photos
  • Why etrailer?

SuperSprings Intl Trailer Leaf Spring Suspension - TSS-107-40

  • Boat Trailer
  • Camper
  • Car Hauler
  • Snow Trailer
  • Utility Trailer
  • Leaf Spring Enhancement System
  • 3000 lbs
  • 4000 lbs
  • 5000 lbs
  • Single Axle
  • Jounce Springs
  • SuperSprings Intl

Improves suspension, handling and safety. Progressive spring rate. Provides additional support as needed so you always have a smooth, comfortable ride.


  • Improves suspension, handling and safety
  • Provides additional support as needed so you always have a smooth, comfortable ride
  • Allows the leaf spring ample movement while cushioning light loads
  • Becomes more rigid as more weight is added
    • Increases stability, providing great performance while hauling heavy loads
    • Raises trailer ride height
  • Works independently side-to-side
    • Helps compensate for off-center loads
    • Reduces body roll when swerving and turning corners
    • Works to eliminate trailer sway
  • Acts as shock absorbers, taking the brunt of bumps and rough roads
    • Reduces load on leaf spring assembly
    • Extends the life of your trailer's suspension
  • Designed to work with a suspension system that is in good working order
  • 2 Jounce-style springs, line relocation bracket, mounting brackets and hardware are included
    • Maintenance-free - no tubing to run or air pressure to monitor like with air springs
    • Simple, no-drill installation
  • Made in the USA


  • Application: 3,000-lb to 5,000-lb single, overslung axle - springs sit over axle
    • For tandem axle applications, use 2 kits
  • Capacity: 500 lbs at 50 percent compression
    • Do not exceed the trailer's weight-carrying capacity
  • Spring dimensions: 5" tall x 4" diameter
    • Compresses up to 70 percent of original height with full memory rebound
  • Required clearance between top of spring plate and bottom of trailer frame: 5-5/16" - 6-1/2"
  • Limited lifetime warranty
  • 30-Day satisfaction guarantee

Note: Does not work with spring plates wider than 4-1/4".

TSS-107-40 SumoSprings 3K-5K Trailer Helper Springs w/Bracket-Overslung

Replaces SuperSprings TSS-104-40

Installation Details TSS-107-40 Installation instructions

Customer Satisfaction Score:

Customer Reviews

SumoSprings Trailer Helper Springs w/ Line Relocation Bracket - Single Axle - 3K to 5K - Overslung - TSS-107-40

Average Customer Rating:  4.8 out of 5 stars   (58 Customer Reviews)

Improves suspension, handling and safety. Progressive spring rate. Provides additional support as needed so you always have a smooth, comfortable ride.


Easy install. It took me approximately 3 hours for the entire project. That's cleaning a few things up also. I did not notice much difference in "body roll". Honestly,, I never had much before. Now, anytime going over rougher roads, railroad tracks, etc.... That was a big difference. It took a lot of that movement out. I hardly knew the trailer was going over it. I installed these on a 5th wheel.


One year in already? Wow time flies! These sumo springs have been a GREAT addition to our 32' travel trailer. Easy to install and they've been perfect ever since. I definitely recommend these!

Still so glad we got these ... Things stay put in the trailer, no matter how bumpy the roads get!
Matthew - 10/01/2022


After installing the trailer specific sumo springs the trailer is more stable when towing. I would recommend this easy upgrade to your towable RV.


I had always taken the clover leaf ramps on freeways slow while towing my trailer from fear of tipping. It's stupid, but I feel much better going traffic speed on the ramps now with these springs installed on the trailer. I also feel more comfortable towing with side winds. I don't have a lot of experience towing in high winds, but the few trips I have done with moderate winds felt safe.


Installation was very straightforward and they made a significant difference in pulling.

Springs are still getting the job done~!
Tom - 02/28/2022


These were very easy to installed and have done a great job smoothing out the ride of the camper. It has made a big difference in how the camper tows and has calmed it down with crosswinds and when big trucks pass by. We did not have the clearance to install a shock kit and the tech at etrailer highly recommended these, I am glad he did. So far I am very happy with this product.

These are still going strong after a year of abuse from these horrible roads. I still feel that they have done a lot to smooth out the ride of the trailer.
Dale - 07/25/2020


The only reason I can't give a 5 star is that we haven't taken the trailer out yet to test the sumo's.
From the install point of view, they were great! easy to follow instructions and assembly.

My only suggestion comes from my own mistake. Maybe consider adding an additional line to your step 1. "Ensure the landing gear / jacks / stabilizers are retracted before taking measurements". I had measured and installed two sumo's before I realized the gears were still down which, obviously, messed up my measurements. Thus I had to take off the sumo's, hook up the 5th wheel, raise the jacks, then restart the process. Went smooth after that. My daughter installed one with no problem. Thanks.

I believe they are working as advertised. They smooth out the bumps felt inside the trailer. I also installed sumos on our pickup. They make a HUGE difference when pulling our 5th wheel. Very satisfied.
Tom - 04/14/2022


This was probally the single best improvement we did to our 2018 Coleman Light trailer. The have helped reduce the ping pong effect, reduced trailer sway when being passed by semis on the road and made the trailer easier to pull in general.


Simple call to identify part number needed, Fast delivery, Clear instructions, Extremely easy install.

Great spring support solution to resolve bounce and sway! Perfect addition to our 2019 Riverstone 5th Wheel
Greg S - 02/27/2021


When I decided to replace the RV trailer leaf springs I decided to update the suspension by adding Sumo Springs as well. The installation was simple and quick. Between and Sumo Springs websites all the information is available for the do it your-selfer. Thanks for shipping to Canada. I will continue to support your company.


Installed with EZ-flex equalizer kit. Easy to install when the suspension is lowered. Make sure to measure the gap between the springs and frame before you take off the wheels. Seems like good quality and does improve the ride.


Kit came with more than I needed but I can see where some trailers might have used different hardware and all scenarios were included in kit. I went with these to help eliminate my tires rubbing against bottom of trailer floor on rough roads "California" and give an overall smoother ride hopefully extending the lifespan of our trailer. I also Installed Dexter EZ Flex at the same time.


They work as described. Would not hesitate to buy again


Was easy to install I removed the wheels which made it easy to access the u bolt flange that they mount to I moved the propane line further away from the area, took about an hour to complete install which included greasing the spring mounts.


They were easy to install and definitely made our 5th wheel handle better. I would have gave them a 5 start but I stumbled into the perfect 5th wheel for me and traded my old one off, so I don't have any long term information.


Trailer is more stable with the sumo springs, easy to install great product.


Received the SumoSprings a day early. The installation on 5th wheel was quick and easy with the provided instructions and Etrailer video. Called to ask if it was ok to use one spacer on rear axle and 2 on front to get correct loading on SumoSprings on both axles and tech said no problem. Can't wait to try it out! I'm confident it will help the highway bounce.


these went on so quickly. We took the trailer for a short drive around town and it felt like driving a new car. Increased stability. Hands down this add on is the cats pajamas. Thumbs up,thanks you much.


No room for the Lippert shock kit (outboard side) so I went with the Sumo Springs. Easy install. The way the kit hugs the frame, there has to be improvement in the rocking from side to side.


Wow, these things make the trailer so much smoother! Great service from Etrailer, as Always!


Great add on to our travel trailer suspension to assist in the ride of our leaf spring suspension. We also have MORryde 3000, HD shackle wet bolts , and X-factor crossmembers on our trailer as well. All of the above makes for a great towing experience as we tow our rig between 10 and 15k miles a year from upstate NY to the Rockies as well as traveling the Adirondack mountains and New England with plans for Alaska after COVID. Another great add are the Goodyear Endurance tires on our trailers....fantastic tires! We have a tpms for our trailer tires and I check tire temperature every 2 to 4 hours of travel
With an infrared thermometer.... safe travels!


Tammie I want to thank you for the personnel attention you gave to my order. The springs came faster then I expected. I just got off the phone with a good friend of mine that just received his Sumosprings from etrailer yesterday. We are both long time customers of etrailer and are extremely happy with your products and service. I always tell fellow RV'ers. about your company and hopefully they will buy from you. The company is lucky to have a dedicated and considerate salesperson like you on their staff. Will start the install today. Thanks again.


Although product was on back order etrailer kept me well informed on order progress which was appreciated. Seems to be a great product,untested at this time. Very easy installation ,hoping for the best.

Have had a great experience with sumospings on 31ft 5th wheel,8500 miles, smoother ride and less internal movement of objects.
Terry - 02/21/2021


Short of installing independent suspension or adding shock absorbers (did this on my 2014 radiance, DIY project, lots of upside down drilling) this is the upgrade for you. Installation and directions are straight forward and only took me about an hour to install. Due to the COVID, we were only able to take four trips since we purchased our 2020 Grand Design 303RLS and these helper springs have made a WORLD of difference. The side to side motion is less and the ride is MUCH smoother. Also changed out our fifth king pin which helped with the chucking. Highly recommend these helper springs and as a bonus, dealing with etrailer is a great experience and they are always there to help and support. Customer service is Top Notch.


etrailer has delivered again. Great company for your RV parts. Looking forward to next trip to see how Suspension Upgrade works, but took trailer for short 10 mile test pull, & so far I think I'm going to be impressed.

Show More Reviews

See what our Experts say about this SuperSprings Intl Trailer Leaf Spring Suspension

  • Troubleshooting SumoSprings Compressed 1/2 to 2/3s After installation
    I spoke with my contact at SuperSprings to find out if this would present any issues for you. Although the amount of compression you are describing with the # TSS-107-40 installed is not ideal, they assured me that the system would still work as intended and would not cause a problem. With the amount of compression you are describing, you may need to replace your leaf springs. If you provide me with the measured distance from center eye to center eye as well as the capacity of your axle...
    view full answer...
  • Which SumoSprings Suspension Kit Fits 2021 Winnebago 2401 RG
    I looked up the axle capacities of your 2021 Winnebago 2401 RG and based on that the SumoSprings part # TSS-107-40 that you referenced would be correct. Your trailer would have 3,500 lb axles and this fits axles between 3,000-5,000 lb.
    view full answer...
  • Will SumoSprings Trailer Helper Springs fit Fifth Wheel Trailer with 4,400 lb Axles
    The SumoSprings Trailer Helper Springs w/ Line Relocation Bracket # TSS-107-40 will work with 4,400 lb axles. It will fit your trailer so long as the axle is an overslung axle, which means the leaf spring will be over the axle. If you take a look at the accompanying cut out of the linked installation manual you can see how the springs will mount and what your axle needs to look like for the helper springs to work. When installed the SumoSprings # TSS-107-40 will be a good addition to...
    view full answer...
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  • Using SumoSprings Trailer Helper Springs In Place of Shock Kit on Trailer
    The SumoSprings Trailer Helper Springs # TSS-107-40 are a great alternate solution to the Lippert Shock Kit that you mentioned when you don't have the needed tire to frame clearance. The jounce-style urethane springs will essentially act as shock absorbers to take a lot of the jolt out of bumps and rough roads and will definitely work to prolong the life of your suspension. Because they won't be constantly engaged like traditional shocks they aren't going to have quite the same effect with...
    view full answer...
  • Sumo Springs Versus Shocks for Toy Hauler
    Because they are maintenance free, less expensive and easier to install than shocks, I'd definitely recommend going with the SumoSpring option. They'll work with your existing leaf spring suspension to help dampen the suspension, but will also reduce sway and body roll during turns. For a tandem axle application, you'll need two sets of the # TSS-107-40 which are compatible with 3000-5000 lb capacity axles. As a bonus, the SumoSprings are also especially effective against porpoising, the...
    view full answer...
  • SumoSprings Helper Springs on a 5th Wheel with Under-Spring 7k Tandem Axle
    I'm happy to inform you that the SumoSprings Trailer Helper Springs, part # TSS-107-40, will work for your setup. They are designed to sit over the axle and can handle axles between 3K and 5K. I've linked to a video review of these springs for you to look at. Keep in mind that since you have a tandem axle, you will need 2 kits. You can check the product page for this kit's current price.
    view full answer...
  • Will SumoSprings 7k Trailer Axle Kit TSS-107-40 Fit 2016 Grand Design 350M Toy Hauler
    Yes the SumoSprings Trailer Helper Springs w/ Line Relocation Bracket # TSS-107-40 will work on your tandem 7k axles. Since this is a single axle kit you'd need a quantity of two of the # TSS-107-40.
    view full answer...
  • Suspension Upgrade For 2007 Keystone Everest 344J
    There are suspension upgrades available for the 2007 Keystone Everest 344J but they are not designed to raise your carrying capacity of the fifth wheel trailer. The carrying capacity of your trailer is set by the manufacturer and cannot be changed. Suspension enhancement is designed to support the existing suspension on the trailer to prevent sagging, improve ride quality, and prolong the life of your suspension components. The carrying capacity I was able to find on line for the Keystone...
    view full answer...
  • Is The SumoSprings Trailer Helper Springs TSS-107-40 A Set Or An Individual Spring?
    The SumoSprings Trailer Helper Springs w/ Line Relocation Bracket - Single Axle - 3K to 5K - Overslung # TSS-107-40 you were looking at comes with both the right and left hand springs and all of the hardware needed to get them installed on your trailer. Keep in mind the # TSS-107-40 is designed for 3000lb - 5000lb axles that have overslung springs meaning the springs are on top of the axle. I included a video of the # TSS-107-40 for you to take a look at.
    view full answer...
  • Can SuperSprings TSS-107-40 Trailer Suspension Helper Springs Be Cut Down if Too Tall to Fit
    According to the folks in the engineering department at SuperSprings, the manufacturer of SumoSprings it is acceptable to cut down the SumoSprings if necessary, but be aware that doing so will void the product warranty. SuperSprings recommends cutting as little as possible off the springs.
    view full answer...
  • How Wide can the Bracket on a SumoSpring TSS-107-40 Adjust to?
    I had the bracket SumoSprings Trailer Helper Spring # TSS-107-40 measured, and it will go from 4 1/2 inches at the widest and 3 3/4 at it most narrow positioning. Not knowing how wide the plate is for your MORryde shock kit is, you will need to measure to make sure this will fit or not.
    view full answer...
  • Suspension Enhancement For 2020 Jayco Jay Flight SLX 244 To Reduce Trailer Tilt and Lean
    To better stabilize your trailer from all the tilting, I recommend the SumoSprings Trailer Helper Springs # TSS-107-40. They are a progressive jounce spring that will work individually at each leaf spring. They can provide up to 500lbs of support to the suspension helping to reduce the trailer movement.
    view full answer...
  • Recommended Preload for SumoSprings TSS-107-40 Trailer Helper Springs
    The folks at SuperSprings tell me that ideally, you'd see about 1/4 inch of pre-load between the # TSS-107-40 spring and the underside of the trailer frame, but they tell even if there's no preload, the SumoSprings would still provide benefit. You can even trim the spring if you need to, but SumoSprings cautions that doing so will void the warranty.
    view full answer...
  • Can SumoSprings # TSS 107-40 be Used with Shock Kit Installed on Trailer
    The SumoSprings Kit part # TSS-107-40 would work just fine on a trailer with shocks like what you have. The shocks will still provide the dampening to make it feel less bouncy and harsh whereas the SumoSprings would just give you more support which reduce the bouncing. If you are getting sway though I would recommend you try moving the weight of any cargo in the trailer as far forward as you can and also make sure you are using a ball mount that allows the trailer to sit level as well.
    view full answer...
  • Correct SumoSprings for Keystone Passport Elite Travel Trailer 4,400 Lb Axles
    The correct SumoSprings Trailer Helper Springs for overslung axles (axle under leaf springs) is part # TSS-107-40. The springs will be pre-loaded upon installation therefore the space you have between the frame is spring loaded will be less than the height of the spring and bracket. This won't be an issue.
    view full answer...
  • Recommended SumoSprings Trailer Helper Springs for 2021 Grand Design Reflection 5th Wheel
    SuperSprings recommends the # TSS-107-40, which is designed for 3000-5000 lb capacity axles. Once installed, the springs would sit so the top is 6-1/2 inches above the top of the spring pack. Two 1/2 inch thick spacers are included, so if one spacer was added, it would sit 7 inches above the spring pack and 7-1/2 inches if both spacers are used. Ideally, you'd want to see about 1/2 inch of preload. To determine if the # TSS-107-40 would work, with the trailer on the ground as you'd typically...
    view full answer...
  • How to Determine What Trailer Helper Springs TSS-107-40 Will Fit
    I can help you to determine if the SumoSprings Trailer Helper Springs # TSS-107-40 will fit your trailer, though there isn't a list or anything similar with fits; it is a universal type of fit. In order to determine if this will work for your 2011 trailer there is some necessary information you need to have, which is simply the weight rating of your axles and to know if they are overslung - which means the leaf springs will be on top of the axle beam as opposed to under. If your boat trailer...
    view full answer...
  • Recommended Suspension Helper for Stock Trailer
    I'm not aware of any air bag systems that can be used on trailers, but there are some great options available for jounce style springs that sit on the axles and add some extra cushion; a good example of these are the SumoSprings Trailer Helper Springs w/ Line Relocation Bracket - Single Axle - 3K to 5K - Overslung # TSS-107-40. These helper springs are designed for single axle trailers with 3000-lbs to 5000lbs capacity, but if you can let me know the specs on the axle of your trailer and...
    view full answer...
  • Which Will Have Greater Impact on Trailer Stability SumoSpring or Cushioned Equalizer
    For side to side stability on your camper the SumoSprings like # TSS-107-40 is going to be the bigger improvement than an upgraded equalizer. An upgraded equalizer will basically cushion the ride quality but it won't make a significant change in the stability like the SumoSprings. The SumoSprings will provide independent support to either side of the trailer's suspension which will help prevent the trailer from being affected by the wind gusts whereas the cushioned equalizers would basically...
    view full answer...
  • Recommended Helper Springs for Tandem Axle Boat Trailer with 5K Axles
    I'd recommend the SumoSprings # TSS-107-40 for overslung axles with a 3000, 4000 or 5000 lb capacity. The springs mount to the top of the spring pack and will contact the underside of the trailer frame when compressed. The kit includes 2 springs and the mounting hardware, so for a tandem axle trailer you'll need two kits. The SumoSprings will improve your ride and handling while reducing sway and will reduce roll during turns. I've linked to a product demonstration video that you might...
    view full answer...
  • Will SumoSprings Kit # TSS-107-40 Fit Trailer with Overslung Axles
    Yes, since you are moving your axle setup to be an overslung setup the correct SumoSpring kit you need is the part # TSS-107-40 as long as your axles are between 3k and 5k.
    view full answer...
  • How Much Preload Should SumoSprings kit for Trailer Suspension Have When Installed
    One inch of preload is too much for the install of the SumoSprings kit part # TSS-107-40 that you referenced. You want between 1/4 and 1/2 inch of preload otherwise you'll have a harsher ride quality. If you have spacers installed you would need to remove them so that the preload lowers. This process is outlined in the attached install instructions link.
    view full answer...
  • Can SumoSprings Trailer Helper Springs be Cut to Fit Trailer Correctly
    You definitely can cut the SumoSprings Trailer Helper Springs # TSS-107-40 to fit your application if you don't have enough room. We have confirmed this with SuperSprings on multiple occasions. You might also want to make sure that you haven't overloaded your trailer and that your leaf springs are in good shape. Unless you put larger tires on your Keystone Cougar 26RBS than what came as stock you shouldn't be having the tires bump up against the underbelly material unless you are flying...
    view full answer...
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  • Can SumoSprings Trailer Helper Springs be Used on Slipper Spring Setups
    Yes, the SumoSprings Trailer Helper Springs part # TSS-107-40 that you referenced can be used with slipper springs and since you have 3,500 lb axles it would be exactly what you'd need as well.
    view full answer...

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