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Timbren Suspension Enhancement System - Severe Service - Rear Axle

Timbren Suspension Enhancement System - Severe Service - Rear Axle

Item # TGMRTT15S
Our Price: $252.45
You Save: $44.55
Vehicle Suspension

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7,000-lb Capacity hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. Provides a comfortable ride by absorbing road shock and improving stability. Ideal for trucks with slide-in campers or an in-bed salt spreader. Great Prices for the best vehicle suspension from Timbren. Timbren Suspension Enhancement System - Severe Service - Rear Axle part number TGMRTT15S can be ordered online at or call 1-800-940-8924 for expert service.
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Timbren Vehicle Suspension - TGMRTT15S

  • Jounce-Style Springs
  • Rear Axle Suspension Enhancement
  • Timbren
  • Extra Heavy Duty

7,000-lb Capacity hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. Provides a comfortable ride by absorbing road shock and improving stability. Ideal for trucks with slide-in campers or an in-bed salt spreader.


  • Improves suspension, handling, and safety
    • Ideal for trucks with slide-in campers or an in-bed salt spreader
  • Provides additional support as needed, so you always get a smooth, comfortable ride
    • Allows the leaf spring ample movement and cushions light loads
    • Becomes more rigid as more weight is added
      • Increases stability - gives you great performance when you are hauling heavy loads
      • Reduces rear sag
  • Works independently - side to side
    • Helps to compensate for off-center loads
    • Reduces body roll when you have to swerve or execute a sharp turn
  • Acts as shock absorber, taking the brunt of bumps and rough roads
    • Extends the life of your suspension
  • Includes 2 Aeon hollow rubber springs, custom-fit brackets and hardware for simple installation
    • Replaces axle bump stops on frame
    • No drilling required


  • Capacity: 7,000 lbs
    • Do not exceed your vehicle's weight-carrying capacity
  • Designed to work with a suspension system that is in good working order
  • Severe Duty should be used if a lot of weight will be towed long distance
  • Limited lifetime warranty - satisfaction guaranteed

An example of sag on a truck's rear axle under a heavy load. The Timbren Suspension Enhancement System levels the vehicle.

Whether you're hauling heavy loads in the cargo area or by pulling a trailer, you will often see the rear sag while the front end rises. In these cases, the rear axle is handling not only the weight of the cargo, but more of the truck's weight, as well. Because less weight is on the front axle, the front tires are making less contact with the road. Overall handling - traction, steering, and braking - is negatively affected. But the resistance from Timbren's Suspension Enhancement System works with your factory suspension to keep your vehicle level and improve your driving experience.

Diagram of the Timbren spring installed

The Timbren system has a custom-fit bracket that will be bolted onto each frame rail above the rear axle. Hollow rubber springs are bolted to the bottom of the bracket and hang down to where the bottom of the spring sits, one inch above the axle. The inch of clearance allows the existing factory suspension to operate normally under light loads and standard terrain, ensuring the smooth, comfortable ride that you are used to.

Animation of a standard Timbren rubber spring

Timbren Suspension Enhancement Systems are designed to work progressively. When the hollow rubber springs are compressed, the convoluted design causes them to quickly collapse along the folds. Once the folds are compacted, the stacked barrel shape increases resistance, stiffening the suspension and keeping the truck level.

Timbren suspension system works to prevent body roll

Each hollow rubber spring works independently to support the driver's or passenger's side of your vehicle. This is helpful when you swerve or make sharp turns. Each spring is activated when it is needed, so body roll is greatly reduced. The independent action also works well when you are hauling off-center loads.

An example of a trailers swaying

Because the vehicle handles better with the springs, less turbulence will be passed along to the trailer, and this helps to keep the trailer in line. Your driving comfort is further enhanced if the trailer does begin to sway (from a gust of wind or a passing semi), because the movement from the trailer is not transferred to the truck. This also works to make the sway subside more quickly.

An empty truck on a bumpy road without Timbren

Another great feature of the rubber construction is that the springs absorb most of the road shock, creating a smoother, more stable ride overall. Wear and tear on the factory suspension is also lessened because the rubber springs work to prevent bottoming out on rough roads.

Compared to the Competition

Timbren's suspension enhancement systems are much easier to install than air springs - there are no air hoses to run, no compressors or gauges to hook up, and no manual adjustments to make. The rubber construction makes Timbren's springs more elastic than similar products constructed of microcellular urethane. And more elasticity allows for a more comfortable ride because the rubber has more travel.

GMRTT15S Timbren SES with Aeon Hollow Rubber Springs - Rear Axle - Severe Service

Installation Details TGMRTT15S Installation instructions

This Product Fits The Following Vehicles

Customer Satisfaction Score:

Customer Reviews

Timbren Suspension Enhancement System - Severe Service - Rear Axle - TGMRTT15S

Average Customer Rating:  4.7 out of 5 stars   (4786 Customer Reviews)

7,000-lb Capacity hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. Provides a comfortable ride by absorbing road shock and improving stability. Ideal for trucks with slide-in campers or an in-bed salt spreader.


I don't know what I thought this was, but, it definitely was not that. In my mind, this is just a fancy spring stop that replaces the one supplied by the manufacturer. Because of the thickness, my truck bottomed out more and quicker than with the factory stops. I had in my head (from reading from others) that this would help the suspension softness. It did not.
I ended up putting airbags on the truck. It had weaker springs due to age (2005 model) and the stop would not help that. The airbags were a blessing. They eliminated the too-soft ride. Had I put the airbags on first, I doubt I would have ever put this product on. (Although we did find out that the factory stops were worn out and needed replacement.)
I can not, and will not, degrade this product as it is well made and it was exactly as it was advertised. It just was not the product that I needed. Make sure what you need BEFORE you buy.

The Timbren springs will be more robust and larger then the factory stops. This means when the truck is unloaded and the truck goes over bumps, the springs will hit the frame quicker which can make a rougher ride for some. Air bags are a good alternative if this would be bothersome.
-- Etrailer Expert Jenny N - 09/20/2022


The overload boosters made a big difference in my truck’s ability to handle a truck bed camper. Works well!


Truck rides like a go-cart after installation. The ses is resting on the axle when truck is unloaded. Not happy at all.

There should be about 1 inch to 1 and a half inch of space between the axle and spring when the 2014 GMC Sierra 1500 is unloaded. You can achieve this by removing the spacer. That will improve the ride quality.
-- Etrailer Expert Heather A - 02/03/2022


Everything arrived as promised been towing with the product a week or so really helps with truck Sway and bounce


They are great when you are loaded heavy or towing. They destroyed my pickups ride when empty. I have considered airbags ever since I installed them.

2002 GMC Sierra

i was pleasantly surprised to how easy installation was


Quality,super fast shipping. Never any problems.

2016 GMC Sierra 1500

No instructions were included. I tried to find something on line but I couldn't find anything that looked like my kit.

Sorry that instructions werent included. If you use the link provided, you can see or print the installation instructions.
-- Etrailer Expert Mike L - 04/28/2018


Great product, stopped sagging problem when pulling trailers


When towing travel trailer, too harsh of a ride, like a log wagen. Bought air lift AL59565 and they ride great.


I ordered it late Monday received it Wednesday very fast turn around good price helpful customer service overall very pleased I installed it same day using it for a trip next day Thanks


it gave a terrible ride. removed from v ehical


Easy to Install work great

2006 Chevrolet Silverado

Good product, good quality...





Used product before worked as expected service very good.

2017 GMC Sierra 1500

2015 Chevrolet Silverado 1500

Very easy install... A little early to know how well it works.





Review from a similar Timbren Aeon Spring System in Vehicle Suspension

The hardest part was the de-installation of the factory bump stop. Installation of the Timbren’s was simple and easy.

My truck is 2008 F250 V10 Crew Cab 4x4 with factory overload springs. I have a B&W fifth wheel & gooseneck hitch installed. I did notice the difference in towing my 34’ fifth wheel trailer. The ride and handling was improved. I would recommend them.


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

About a 1/2 inch difference in gap at the bump stop perch but still within parameters. Truck sits perfect with trailer attached. Haven’t towed yet. After towing if they perform like they should will upgrade to a 5 star. Easy to install, definitely needed 2x4 and jack. 2011 Silverado ext cab with 30 ft Genisis 5th wheel.

Show More Reviews

See what our Experts say about this Timbren Vehicle Suspension

  • Timbren Suspension Enhancement for a 2008 Chevy Silverado with a 5th Wheel Trailer Hitch
    The Timbren system, # TGMRTT15S, installs on the bottom of the frame. As long as the 5th wheel bracket does not wrap around to the bottom of the frame it will not interfere. Timbren lists this kit as a fit for service vehicles only. I have included a link to the installation instructions for you to view. For a non-service vehicle, use # TGMRTT15S. It installs the same way and will not interfere. I have linked instructions for this kit as well as a link to our FAQ article on Timbren systems...
    view full answer...
  • What is the Warranty on the Timbren Rear Suspension Enhancement System
    The warranty of this Timbren Rear Suspension Enhancement System # TGMRTT15S is for the lifetime of your vehicle as long as your vehicle is under normal use. It is hard to say exactly how long it would take for you to install the # TGMRTT15S on your 2011 CHevy Silverado, but after looking at the instructions I would imagine it would not take you more than an hour as long as you have basic mechanical skills and access to tools. I attached installation instructions for this product for you...
    view full answer...
  • Suspension Enhancement Recommendation 2001 Chevy Silverado 1500
    There aren't any products out there that will give you additional towing capacity. We have suspension enhancement kits for your 2001 Chevy Silverado 1500 like the # TGMRTT15S which will help the vehicle carry it's capacity in a safer manner.
    view full answer...
  • Suspension Enhancement Recommendation for 2017 Sierra Towing Fifth Wheel Trailer
    For your 2017 GMC Sierra 1500 towing a fifth wheel trailer the best option we have for suspension enhancement is the Timbren kit part # TGMRTT15S as it will provide you with an additional 7,000 lbs of suspension support when needed. The air bag kits for your truck aren't designed for fitting with an in-bed fifth wheel or gooseneck hitch so I would not recommend that route.
    view full answer...
  • Why Would Trailer Brakes Lock Up When Running Lights are On
    There's a short on your trailer wiring between the running light circuit and the brake output circuit that runs to the trailer brakes. Look for exposed wire or corrosion on the wiring and connectors and you'll find the short. Rear suspenion enhancement like the Timbren kit part # TGMRTT15S would be a great way to help with towing. It will give more more support to the rear suspension to allow it to tow level.
    view full answer...
  • Timbren Rear Suspension Enhancement System TGMRTT15S Height
    The Timbren Rear Suspension Enhancement System part # TGMRTT15S for the 2000 GMC Sierra 1500 springs themselves measures 3-1/4" tall. If you use the spacer the spring will be 4-1/4". Timbren does require 1/2" and 1-1/2" between the rubber spring and the contact point when not loaded down.
    view full answer...
  • How Hard are The Timbren Jounce Springs TGMRTT15S To Install On a 2020 Chevrolet Silverado 1500?
    The Timbren Rear Suspension Enhancement System # TGMRTT15S for the 2020 Chevrolet Silverado 1500 are very easy to install. I have linked the instructions for them below. To remove the factory bump stop you need a 10mm deep well socket and the Timbren springs will bolt in their place with the new hardware.
    view full answer...
  • Timbren Suspension System Recommendation for a 2014 GMC Sierra 1500
    The difference between the two Timbren systems you referenced is the application for each. The Timbren Rear Suspension Enhancement System - Severe Duty # TGMRTT15S is designed for service vehicles only so it would not work for you. The # TGMRCK15S would make an excellent choice for a suspension enhancement system for your vehicle. This system has plenty of capacity for the ton of pellets you carried, and is great because when your vehicle is unloaded your ride quality will be exactly the...
    view full answer...
  • Comparing Timbren Suspension Enhancement for 2019 Chevy Silverado 1500
    The difference between the two Timbren Suspension Enhancement Kits that fit your 2019 Chevy Silverado 1500 is that the Timbren # TGMRCK15S are designed to support daily driver trucks for towing and heavier loads, while the other option, part # TGMRTT15S, is designed for service vehicles like a tow truck. The reason for that is their design, with the service vehicle option being much more rigid and stiff for that type of work. Due to that, for your 2019 Chevy Silverado 1500, I highly...
    view full answer...
  • How to Remove Rear Axle Bump Stops on 2014 Chevy Silverado 1500 4x4
    All of the Timbren and other rear-axle jounce-spring kits we have for your 2014 Chevrolet Silverado 1500 4x4, shown on the linked page, feature a bolt-on installation. If you refer to the linked page for Timbren kit # TGMRCK15S you will see in the product image photos three diagrams showing different installation methods, including the one I linked for you, which shows a cup-type mount as found on 2007-2008 model years. Your truck should be a bolt on, however. A socket extension will be...
    view full answer...
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  • Difference Between Timbrens TGMRCK15S & TGMRTT15S For 2017 & 2021 Chevy Silverado 1500
    So to answer your first question, both of these Timbrens will fit on both a 2017 and 2021 Chevy Silverado 1500 (so long as your truck does not have the Adaptive Ride Control). The biggest difference is what type of vehicle they are designed for. The # TGMRTT15S is designed for service or work vehicles (like tow trucks, for example) and are much stiffer than needed for a standard passenger pick-up truck. So what I assume you have, and can use on both trucks, are the Timbren Rear Suspension...
    view full answer...
  • Best Timbren Suspension Enhancement For 2017 Chevy Silverado 1500
    The Timbren # TGMRTT15S is for service vehicles such as tow trucks; they are very stiff and for a standard 2017 Chevy Silverado 1500 truck that is for towing, you definitely don't want to use those. The best Timbrens for your '17 Silverado 1500 will depend on if you have the MagneRide suspension or not: - WITHOUT MagneRide: Timbren Suspension Enhancement System # TGMRCK15S - WITH MagneRide: Timbren Suspension Enhancement System # TGMRCK15MR I do recommend Timbrens for towing, as they'll...
    view full answer...
  • Can Timbrens be Used with RoadActive Suspension Kit on 2011 Chevy Silverado
    For your 2011 Chevy Silverado I recommend starting with the RoadActive Suspension Kit # RAS4611 that you mentioned by itself to see how everything handles when pulling your 34 foot trailer. It wouldn't necessarily be "overkill" to add the Timbren Rear Suspension Enhancement System # TGMRTT15S (the two components can indeed be used together) but maybe more accurate to say that the Timbrens might not really be utilized if the RAS is doing its job. Because the Timbrens will replace the factory...
    view full answer...
  • Which Jounce-Style Suspension Enhancement Should I Install On 2020 Chevy Silverado 1500 Non Mag Ride
    The Timbren and Sumo Spring suspension enhancement systems use a jounce-style spring which is an excellent choice for leveling out your truck and trailer, all while improving handling and reducing trailer sway. They simply replace your factory bump stops and require a simple bolt-in installation process. The SumoSprings Solo Custom Helper Springs - Rear Axle # SS45FR are confirmed to fit your 2020 Chevrolet Silverado 1500 but this only has a 1,500lb weight capacity for the rear of your...
    view full answer...
  • Which Timbren/Suspension Enhancement for 2021 Chevy Silverado 1500
    For your 2021 Chevy Silverado 1500 the better choice between the two Timbren kits you mentioned is the part # TGMRCK15S which was designed for applications like yours whereas the # TGMRTT15S was intended for severe service trucks like tow trucks so the ride quality would be much harsher. Now if you want my recommendation for the best suspension enhancement that fits your truck I would recommend the RoadActive Suspension kit part # RAS54FR which gives you the best support that is also adjustable...
    view full answer...
  • Is There a Timbren Rear Suspension Enhancement Kit that Fits 2006 Ford F-150
    We have a rear suspension enhancement kit from Timbren that fits your 2006 Ford F-150 4x4 with the part number TFR150D but the kit you mentioned does not fit.
    view full answer...
  • Can I Add A Timbren Rear Suspension System To My 2011 Chevrolet Silverado With Roadmaster Suspension
    Yes, you can add The Timbren Rear Suspension Enhancement System # TGMRTT15S to your 2011 Chevrolet Silverado that already has the Roadmaster Active Suspension. The Timbren Suspension system will improve suspension, handling and safety. It will provide additional support as needed, so you always will get a smooth, comfortable ride. The system works independently - side to side and act as shock absorbers, taking the brunt of bumps and rough roads. The capacity of the springs are 7,000...
    view full answer...
  • Will Timbren Suspension Enhancement Fit 2013 Chevy Silverado 1500 With 3 Inch Lift
    Yes they sure will; you'll simply need spacers to accommodate for the 3 inch lift on your 2013 Chevy Silverado 1500. The spacers are 1 inch, so you'll need three of them along with the Timbrens. The correct parts for your truck are the following: - Timbren Rear Suspension Enhancement System # TGMRTT15S - Timbren 1" Spacer For Raised Frame Vehicles - 3/8" Bushing # A25723-90AH00 Timbrens are a really nice choice for your Silverado to help improve its handling and performance when you...
    view full answer...
  • Timbren Suspenion Enhancement and Spacers for a 2006 Chevy Silverado 2500 w/ Lift
    The Timbren Suspension Enhancement System item # TGMRTT15S is 3-1/4" tall. If you use the spacer the spring will be 4-1/4". Timbren requires a 1/2" to 1-1/2" between the rubber spring and the contact point when not loaded down. You will also need to install three of the Timbren Spacers item # A25723-90AH00 on each side equal to the height of what sounds like a 3" lift in order to compensate for your 7-3/4" spacing. You will need to source your own bolts from your local hardware store....
    view full answer...
  • Jounce Suspension Enhancement Springs on a 2005 Chevrolet Silverado w/ 6 Inch Lift
    For your 2005 Chevrolet Silverado we have the Timbren Rear Suspension Enhancement System item # TGMRTT15S. These have a 7,000 lbs capacity and the hollow rubber springs sit above the rear axle to help stabilize and level your Silverado. To accomadate the gap caused by your six inch lift you will need the Timbren 1" Spacer For Raised Frame Vehicles item # A25723-90AH00. The recommended gap between the bottom of the jounce bumper and top of the contact point is 1" but you can have a larger...
    view full answer...

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