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Timbren Suspension Enhancement System - Severe Service - Rear Axle

Timbren Suspension Enhancement System - Severe Service - Rear Axle

Item # TGMRTT35S
Our Price: $398.07
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Vehicle Suspension

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8,000-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 TGMRTT35S can be ordered online at or call 1-800-940-8924 for expert service.
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Timbren Vehicle Suspension - TGMRTT35S

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

8,000-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 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
      • Reduces vehicle sag
  • Works independently - side-to-side
    • Helps compensate for off-center loads
    • Reduces body roll when swerving and turning corners
  • Acts as shock absorbers, taking the brunt of bumps and rough roads
    • Extends the life of your vehicle's suspension


  • Includes 2 Aeon hollow rubber springs, vehicle-specific brackets and hardware for simple installation
    • Replaces axle bump stops on frame
    • No drilling required
  • Capacity: 8,000 lbs
    • Do not exceed the vehicle's weight-carrying capacity
  • Designed to work with a suspension system that is in good working order
  • Limited lifetime warranty - satisfaction guarantee

An example of sag on a vehicle's rear axle under a heavy load

Whether you're hauling heavy loads in your bed or cargo area or you're towing a trailer, you will often see the rear of your vehicle sag while the front end rises. In these cases, the rear axle is handling not only the weight of the cargo, but also more of the vehicle's weight. 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 comes with custom-fit brackets that are 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, 1" 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 your vehicle level.

Timbren suspension system works to prevent body roll

Each hollow rubber spring works independently to support the driver's side 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 your vehicle. 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.

Timbren Suspension Enhancement 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.

GMRTT35S Timbren SES with Aeon Hollow Rubber Springs - Rear Axle - Severe Service

Installation Details TGMRTT35S Installation instructions

This Product Fits The Following Vehicles

Customer Satisfaction Score:

Customer Reviews

Timbren Suspension Enhancement System - Severe Service - Rear Axle - TGMRTT35S

Average Customer Rating:  4.7 out of 5 stars   (6076 Customer Reviews)

8,000-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.


This is the second truck I have used these on and they work great...they don't interfere with the ride...they keep a lot of weight off my springs when I put my camper on my truck. I appreciate the fact they are easy to install!!

2006 Chevrolet Silverado

This review is on a timbren air spring ,I bought this on a Saturday night ,went out of town Monday morning and got in on Thursday afternoon ,wife said the box had arrived Tuesday and put them on this morning on our 2006 Chevy k-3500 ,my guy had the truck in our shop for an oil change and I asked him to put it on, came back 45 min later and he was done with the spring installation and the oil change ! I asked him how hard it was and he said it took him longer to figure out which parts in the kit he needed that the actual install ,said it was about as easy as it gets .Well ,now for the test drive we drove the truck empty ,pretty much as stock ,rode real well.Then we put a Gaylord box that weighed 4506# and drove the truck ,WoW ,What a difference ,truck rode great and handled well ,went over railroad tracks,really handled well and rode great ,I wish I'd have done this years ago ! I highly recommend this product and commend etrailer on their good service and what made me decide to purchase the timbren product was the you-tube video ,after I saw that ,I placed the order ,it looked so simple to install and it went on just like on you-tube

Bryan L.


The air springs have performed flawlessly ,very pleased with the product and performance ! As a matter fact I was recommending this product to a friend the other day.


Excellent product, great instructions for install.


This works great when the truck is loaded, when it is unloaded the ride is too stiff - I used the spacers to help with leveling when the truck is loaded but when unloaded it makes for a rough ride. These do work as promised but I wished I would have sprung for the airbags that I can adjust easily.

Etrailer Expert

Jenny N.


I do have a solution to offer. This kit is designed to work with Severe Service trucks like tow trucks or with slide in campers. It can create a stiffer ride when not being used to tow. I would recommend part # TGMRCK25S for your 2008 Chevy Silverado 2500.



It worked for what I needed it for, I just recently removed the bushings as the normal trailer pulling I was doing is done for now and I wanted the ride quality to return to normal. After removing them, I was a little disappointed that the welds for the bolts broke and everything seemed loose. I can imagine if I had it in service for another year or two it would have failed completely. Maybe that is my fault for not periodically taking it apart and tightening things down again but I did not think that would be necessary as the bushings are just that, bushings.


Put these on a ramp truck I built, I made the deck height as low as possible to the stock frame on a 2009 GMC 2wd. Well, turns out that left me with about 3" or so between the top of the tire and the underside of the deck... when unloaded.

Put a 1600 lb car on it, and it dropped the deck right onto the top of the tires. Couldn't move the truck, it needed more spring. Well, the Timbren severe service Aeon springs were a simple fix, I was willing to try.

Good news, it works like a charm. Even with the car loaded, and me bouncing on the very rear of the deck, I still have a few inches of tire clearance. So far so good!


Awesome thanks

Chevrolet Silverado 2500

So far everything I have purchased from etrailer for my HD 2500 has worked as described.


Bolted in like a factory part, i didnt require the entra spacers. No change in unloaded ride quality, but with 3000# in the bed the truck felt more stable. Im am very happy with it so far.


Thank you kim, cant wait to install in my truck.
Have a great holiday.


2009 GMC Sierra


I know it will be lovely when loaded or the trailer on. However,it rides like a wagon empty with brand new premium shocks and struts empty. Thud thud thud. You really cannot feel the shocks or suspension. Found exact same item plentiful for 60 bucks on eBay after I bought these for 250. I may cut these in half or put air bag on. I do not like the ride empty. No hard feelings. It is a good product maybe just not for me.


Installation was a breeze, removed old bump stops installed Timbrens in about 30 minutes. Haven’t put a load on them yet so I’ll update later. Installed on a 2008 Silverado 2500HD..


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.


Was able to install these with a 15mm flex head ratchet wrench and lifted the rear of the truck to make it easier. 30 minutes to take off 4 nuts and put em back on. 2 minutes assembling the timbrens with the added spacer. I have a f350 with a salter and plow. Loaded with salt the lights shoot up and in the snow ?? it’s like hitting hyper drive and you’re blinded. These helped big time. Very happy so far.


The pro: The longer, heavier bump stops worked great when hauling my mustang home from Chicago. The truck stayed level and handled great.
The con: I had to remove the bump stops for everyday use. They limited my suspension travel causing a stiffer ride.


I am so glad I bought these for my truck. I was able to install them myself using a jack and jackstands. The ride is bit rougher now; but the suspension is totally awesome compared to before. I am able to haul a bit more weight when needed.


Haven’t had it on long, but so far so good. 1999 F350 dually. Bolted up nicely. Total job took 10 minutes. Have hauled two gooseneck loads of hay and truck drives SO much better. Nice and level. Money well spent so far.


very good product ,received just in time and fit perfectly on my GMC savana 2000 .Be sure to clean the two receptacle thats help.
très bon produit , reçu dans les délais et s'ajuste parfaitement . Assurez-vous de nettoyer le receptacle cela facilite l'installation.


The Timbren SES (Bump Stop) replacement for the 3rd Gen Sequoia is a simple and effetive solution to reduce vehicle sag when trailering heavy loads. You definately want to use the included spacer as the pics will show I still had 2 finger clearance above the axle to allow for OEM suspension travel. I pulled my 29ft boat back to back with / without the Timbren bump stops for a ride quality test. Without the bump stops, my 2024 Sequoia rear end was crushed, resulting in a rough ride and poor handling characteristics. With the Timbern bump stops, the rear sag was reduced signifincantly, and the vehicle drove much better. YES, you will feel and occasional bottom out feeling on abrupt G-out dips... But it is no worse than without the Timberns as the stock springs were crushed. My daily drive feels exactly the same as I have the perfect gap between the Timbren bump stop and the axle allowing the OEM suspension to float over road surface without engaging the bump stops. VERDICT: Time will tell with varied passenger loads, speeds, road surface bumps etc., but my initial impression is 7 out of 10. Ultimately, I would prefer air bags, and may install them along with the Timbrens whih I can swap back to the oem bump stop in less than 15 minutes. NOTE: I was able to install the Timbren bump stops without going under the Sequoia. I simply raised the vehicle frame aprox. 4" withoug picking up the rear tire. This gave me adequate room to reach in over the tire and remove the 3 12MM bolts holding the OEM bump stop in place with a 3/8" ratchet and a 4" extension. Then, I put the Timbren bump stop in place and lightly threaded the upper bolt to hold in place. After installing the two lower bolts and smart torquing, then you tighten the top bolt. This allows the bracket to seat against the frame fully as the top bolt hole is slotted to allow movement druing install. Pics will show spacers installed above the bump stops, Installed bump stops unloaded with 2 finger gap, spacers loaded with 750 lbs of tongue weight, and lastly, will show Sequoia stance while loaded. NOTE: The last picture will show my Sequoia loaded WITHOUT the Timbren SES (Bump Stops) and the vehicle is sagging heavily.


The timbrens actually did what they were suppose to do. However, once I starter driving out west I notice the timbrens were riding on the axle which cause the speedometer to jump around depending on the road. I would recommend them if you are hauling or towing a camper or RV. I was going to contact etrailer about maybe removing a spacer for one set however the other set came as one unit. The bottom line is the Timbrens does stabilize your load for safe travels. I will be contacting etrailer soon to assist in correcting the problem...Road trip from Idaho,Colorado,Wyoming,and Utah were beautiful... Thank you etrailer


Installation was easy and straightforward. Haven’t towed with them yet, but the unloaded ride has not at all been negatively affected. In fact unless you hit a big bump you shouldn’t know they are there but they seem to improve handling around turns when there is a shift to either side in the back. It a HD truck so there is some expectation it’s gonna ride like a covered wagon at times. I added these in conjunction with new Billstein shocks and I’m hopeful all that aggravating bouncing or porpoising my fifth wheel does on bad roads and bridge transitions will significantly improve. etrailer was fast with shipping and follow up. I’ll update after towing.


Definitely a must have when towing..stiff without a load but night and day difference while towing my travel trailer, better traction, steering and braking. Easy quick install..only issue I had was with the long bolts they sent with the spacer kit (optional for lift) the bolt diameter was too wide to fit through the holes on the bracket..but a trip to the local hardware store took care of that.


Pros: Cheaper and easier to install than airbags, do the job when load is enough to compress the shock, with added weight or towing, then it stiffens the rear very nicely.
Cons: Doesn't do anything until there is 2-3cm of compressed shock. It sits above the contact point, doesn't touch. Under normal driving, there is no benefit/improved stiffness/anti sway in rear or a leveling of the factory rear sag in a 2022 or newer Toyota Tundra.
If had it to do over, would have put some kind of spacer in between product and upper included bracket, the supplied bolt is long enough to accommodate, to eliminate the gap, and lift the rear 1-2 cm. Should do it anyway, maybe when swapping to summer wheels next month.


I’d seen similar products rated in the 4,000 lb ratings but I went with these. I’m not a mechanic but I removed the factory bump stops and installed both these in 30 minutes or less. I used my rolling jack and lifted from the drop hitch and easily removed the old ones and soapy water and 1/4 twist and these were on. Placed a block of wood in the space between these coils and lowered the jacks then pressed it with my tractor to confirm full engagement. I carry a lot of tools on a 2020 Chevy 2500 I do feel a bit of butt bounce on large bumps but other than that I’m very pleased.

Show More Reviews

See what our Experts say about this Timbren Vehicle Suspension

  • Suspension Enhancement for a 2007 Chevy Silverado Classic Towing a 5th Wheel Trailer
    The pin weight of a 5th wheel trailer is typically going to be much less than the 12,000 pounds springs # TGMRTT35S are rated for. So there is really no need for such a high capacity spring set. I recommend Timbren springs # TGMRCK15S rated for 3,600 pounds. This set should not interfere with the 5th wheel install kit because they mount to the bottom of the frame. I have linked a video showing a typical installation and a link to the instructions for you. If you want a little more capacity...
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  • Correct Timbren Kit Fit for a 2006 Chevy Silverado 3500
    The only Timbren kit that fits the 1500, 2500, and 3500 models of the 2006 Chevy Silverado pickups is the Kit # TGMRTT35S for severe service vehicles. Aside from that all of the other kits are model specific. For your 3500 you'll need the kit # TUR350 rated for 6,000 lbs or the kit # TGMRCK35S rated for 8,600 lbs. I recommend the 6K version if you tow or haul occasionally, but you'll want the 8.6K version if you're towing or hauling on a regular basis. Attached are some review videos...
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  • Can Spacers Be Added To Timbrens for 2009 Chevy Silverado 2500 With Truck Bed Camper
    The correct Timbren Rear Suspension Enhancement System for a 2009 Chevrolet Silverado 2500 when using an in-bed camper is part # TGMRTT35S. This kit is designed to have around 1/2"-1" between the spring and contact point but if you like you can close the distance with the Timbren Spacer For Raised Frame Vehicles part # A25723-90AH00 or part # TA25722-90P00. Please note, you may need to get a longer bolt from a hardware store as well.
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  • Suspension Enhancement Recommendation for 2003 Chevy Silverado 2500 HD 4WD
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  • Can Spacer of Timbren kit part # TGMRTT35S be Left Off of Truck
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  • Recommended Suspension and Sway Support for 2005 GMC Sierra 3500 with In-Bed Camper
    The Timbren Rear Suspension Enhancement System part # TGMRTT35S is a great option for a 2005 GMC Sierra 3500 with truck bed camper. They are actually designed for constant loads like this so they will provide excellent support. They are also maintenance free. That said, you could still experience issues with sway so adding the Roadmaster Rear Anti-Sway Bar part # RM-1109-167 would pair nicely.
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  • Timbren Recommendation for 2008 Chevy Silverado 3500HD Towing Heavy Fifth Wheel
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  • Timbren Kit Recommendation for 2006 Chevy Silverado 2500HD
    You would definitely want to go with the Timbren kit part # TGMRCK25S for your 2006 Chevy Silverado 2500HD over the other kit you mentioned. The other kit is for severe service applications so it would give you a pretty harsh ride quality. The # TGMRCK25S will give you the support you are wanting without killing the ride quality.
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    To start, adding a suspension lift on your 2005 Chevy Silverado 2500HD is going to require either a custom suspension enhancement kit or spacers because using a regular suspension enhancement kit on a suspension lifted vehicle would mean the helper springs would not engage when they are supposed to. Adding a lift can also make the towing capacity unknown (most likely lowers it) so I would not recommend it. Considering that you tow different loads the best option would be to go with air...
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  • How to Choose the Proper Timbren Rear Suspension for a 2005 GMC Sierra 2500 HD
    For your 2005 GMC Sierra 2500 HD, there are two Timbren rear suspension compatible with it. The # TGMRCK25S have a weight capacity of 6000 pounds while the # TGMRTT35S have a weight capacity of 8000 pounds. More than likely you will only need the one with the 6000-pound capacity as the higher capacity one is for trucks that are reaching their payload capacity on a daily basis. Though you're hauling dump trailers every day, that doesn't mean you're nearing your capacity. Of course, if...
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  • Timbren Rear Suspension Enhancement System for a 2003 Chevrolet 2500 HD Silverado
    The correct kit for your 2003 Silverado, 2500 HD with long Bed, is the Timbren Rear Suspension Enhancement System, # TGMRCK25S, which is the correct kit for 2 and 4 wheel drive models. We have a video installation that should be helpful and installation instructions for you to look over, see links. The kit you referred to is designed for 2500 Service vehicles only. Another option for your vehicle is the SumoSprings Custom Helper Springs Kit, # SSR-201, which is a good option if your truck...
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  • Comparing the Timbren Springs and RoadActive for 2004 GMC Sierra 2500HD with In-Bed Camper
    The best option we have for your 2004 GMC Sierra 2500HD with truck bed camper is the Timbren Rear Suspension Enhancement System part # TGMRTT35S. This system is specially designed for vehicles with truck bed campers and will do an excellent job of providing you with both support and stability. The RoadActive Suspension Custom Leaf Spring Enhancement Kit part # RAS4611 is not really going to give you enough support and would not be a smart buy for your particular application in my opinion. The...
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  • Recommended Rear Suspension Enhancement For 2000 GMC 2500 4x4
    If your 2000 GMC 2500 4x4 is a heavy duty C/K Series, the Timbren Rear Suspension Enhancement System # TGMRCK35MA is the confirmed fit. This system is rated for a 10,000 lb capacity. If your 2000 GMC 2500 4x4 is a light duty Sierra, then the Timbren Rear Suspension Enhancement System # TGMRCK25S with a capacity rating of 6,000 lbs is the correct part. The # TGMRTT35S is not a fit for your model year vehicle.
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  • Helper Spring Option for 2007 Chevy Silverado Classic 3500 DRW Towing Heavy Camper
    Timbren does offer a fit for your truck, part # TGMRTT35S but I'd recommend going with the SumoSprings # SSR-201-47-2 instead. The Timbren model is more designed for severe service vehicles like tow trucks, and wouldn't give you the ride quality you're looking for. The SumoSprings would offer 4600 lbs of additional support without ruining your ride quality. The kit is compatible with DRW vehicles. The springs sit inboard of the leaf spring packs, so they won't interfere with your existing...
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  • Jounce Bumper Helper Spring Recommendations for Towing 5th Wheel With 2004 Chevy Silverado
    The 8K Timbren, part # TGMRTT35S is designed for very heavy duty applications such as tow trucks, trucks carrying very heavy slide-in truck bed campers or that have a heavy service body installed. It would be overkill for your needs. For your application, the 6K capacity kit, part # TGMRCK25S would be a better choice. This being said, once the pin weight of your 5th wheel compresses your rear leaf springs and takes up the 1/2 to 1-1/2 inch preload on the Timbrens so they sit on the axle...
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