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  1. Vehicle Suspension
  2. Timbren
  3. Towing/Load Leveling
  4. Bump Stops
  5. Rear Axle Suspension Enhancement
  6. Extra Heavy Duty
THIS ITEM IS NOT A FIT FOR
1975 Chevrolet Suburban
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Timbren

Timbren Suspension Enhancement System - Severe Service - Rear Axle

Part Number: TFRTT1525
In Stock
$269.36
Retail:$316.90
You Save: $47.54
Vehicle Suspension
Not Confirmed to Fit

1975 Chevrolet Suburban

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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 TFRTT1525 can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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Timbren Vehicle Suspension - TFRTT1525

Highlights

  • Custom Fit for Your Vehicle: Mounts to existing attachment points
  • 7,000-lb Load Support: Keeps your truck level and stable when hauling or towing heavy gear.
  • Smoother, Safer Ride: Rubber springs absorb bumps and reduce body roll for better control.
  • No Drilling Needed: Bolt-on brackets replace factory bump stops for quick DIY setup.
  • Handles Uneven Loads: Each spring works independently to balance off-center cargo.
  • Protects Suspension Life: Cushions impacts and helps prevent bottoming out on rough roads.

Features to know about

Stay Level Under Heavy Loads: 7,000-lb Rear Axle Support

When you pile on the weight—like a camper, salt spreader, or loaded bed—rear sag can throw off handling and braking. The Timbren Suspension Enhancement System adds 7,000-lb capacity hollow rubber springs above the rear axle to help stabilize and level your ride. They provide extra support only when you need it, letting your leaf springs move freely under light loads while firming up automatically as weight increases.

Smooth Out the Bumps: Progressive Rubber Springs That Absorb Shock

Rough roads and uneven loads can beat up your suspension and make driving uncomfortable. These Aeon hollow rubber springs act as shock absorbers, cushioning bumps and rough terrain so the ride stays smooth and steady. The convoluted shape collapses progressively as the load increases—soft when empty, firm when full—so your vehicle stays comfortable and controlled no matter what you’re hauling.

Timbren suspension system on a truck showing improved shock absorption and prevention of bottoming out over rough terrain.

Handle Corners and Off-Center Loads with Confidence: Independent Spring Action

Sharp turns or uneven cargo can make one side squat more than the other. Each Timbren spring works independently to support its side of the vehicle, helping keep things balanced even with off-center loads. This action cuts down body roll during swerves or quick lane changes and keeps sway to a minimum when passing trucks or driving through crosswinds.

Timbren suspension system illustration showing reduced body roll and sag when hauling heavy or uneven loads.

Towing demonstration showing reduced trailer sway due to Timbren suspension system improving vehicle stability.

Keep It Simple: Bolt-On Install with No Air Lines or Adjustments

Getting real load support doesn’t have to mean running hoses or compressors. This kit bolts onto existing frame points above the axle in place of the factory bump stops—no drilling required. With custom-fit brackets, included hardware, and no air pressure to monitor, it’s a straightforward install that’s ready to work as soon as it’s bolted up.

Specs

Weight and Capacity

  • Capacity: 7,000 lbs

Compatibility

  • Designed to work with: a suspension system that is in good working order

Diagram comparing a vehicle’s suspension with Timbren springs in unloaded versus loaded conditions, showing compression of the rubber springs to level the rear axle.

Warranty

  • Limited lifetime warranty: satisfaction guaranteed

FRTT1525 Timbren SES with Aeon Hollow Rubber Springs - Rear Axle - Severe Service

Installation Details TFRTT1525 Installation instructions

This Product Fits The Following Vehicles




Video of Timbren Suspension Enhancement System - Severe Service - Rear Axle
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Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Detailed Breakdown of the Timbren Suspension Enhancement System-TFRTT1525

Hello, Steven here with etrailer.com. Today we're gonna be taking a look at this Timbren Suspension Enhancement System for your rear axle. Now these jounce stoppers, as they're called, are gonna improve your suspension, your handling, and your overall safety. They work really good for trucks that have like a sliding camper or maybe your spreading salt and that kind of stuff in the wintertime, these are gonna give you that boost of suspension to help you not bottom out, sag, and also keep your truck lights, tow vehicle lights, straight level where you want 'em. They are gonna improve the comfort of your ride and they allow the leaf spring ample movement and at it cushions light loads. That way, it's more rigid when the more weight is supplied, but when you have a light load, it basically is never touching your spring on the light load, so it's not messing with your stock performance.

Now this kit is gonna reduce rear sag, like I was just mentioning. They do work independently, side to side, so driver to passenger side. They will help to compensate for off-center loads as well. They will also reduce body roll when you have to swerve or maybe execute a sharp turn or something like that, they're gonna take the brunt of the bumps in the rough roads and they're gonna extend the life of your stock suspension. You will get two Aeon hollow rubber springs, the custom fit brackets for the frame of your particular vehicle, and you're gonna get all the hardware you need to make that install.

Now this is a no drill setup, so I've just kind of stacked these pieces. I'll kind of make sure you a close up of that, hardened steel, powder coated. Then you've got a little spacer block here. And then, of course, you've got the Aeon hollow rubber spring. So those simply get stacked, like so, and then they mount with the bracket on the frame of the truck.

Now it does come with a set of instructions as well. You're gonna get that. That'll help you with your install. And like I said, they are a limited lifetime warranty. They're rated up to 7,000 pounds capacity.

Never, never exceed your vehicle's weight carrying capacity. They will work with the suspension system that's in good working order. And there's no drilling required, whatsoever, so it's a pretty easy install. Now these are going to replace your current axle bump stops that are on your frame already. You'll simply remove those and these will replace it. Again, pretty simple install. Now these are a custom fit, so anytime we have a custom fit item, I recommend you using our website, year, make, and model, our fit guide on etrailer.com to make sure they're gonna fit your needs. This particular kit here that today I'm showing you fits a 1997 to 1999 Ford F-150 and F-350 Light Duties, and it also fits the 2000 to 2003 F-150s. Well, I hope that our time together today has been helpful for you. I'm Steven with etrailer.com. Thank you so much for joining me.

Ratings & Reviews

4.5

967 reviews
5 Stars
(719)
4 Stars
(137)
3 Stars
(29)
2 Stars
(34)
1 Star
(48)
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by:
2003 Ford F-150
The Timbren rear suspension enhancement system did help my 2003 Ford F-150 a lot, I am extremely satisfied with the product and the rest of other products I purchased before from www.etrailer.com . It was an easy set up that didn't take more the 20 mins. to install. I will definitely recommend it and will continue to shop from this place, customer service is a big +, I'm really happy with them.
by:
1998 Ford F-150 and F-250 Light Duty
easy install. bought these in prep for a truck camper purchase.
by:
by:
1997 Ford F-150
by:
Works well on my F250 6.75 bed with a 1700lb dry Capri Retreat camper. Solved 4" squat without airbags. Eliminated sway in high winds.
Heather A. profile picture
Etrailer Expert

Heather A.

5/26/2026

Wow, that is exactly what we love to hear about these springs! That is a serious camper. Any plans with it this summer?

by:
These things made my soft spring toyota into a beast with hurting my ride quality. They take over when heavy weight hauling is needed and dont affect anything when empty! No air lines to leak no bags to break. Just bullet proof indestructible rubber that works every time! Love them, 100% recommend
Jameson C. profile picture
Etrailer Expert

Jameson C.

11/5/2026

thats really great to hear!

by:
I have Timbrens on an F350. We have a heavy truck camper that we use multiple times a year. I've had both these and airbags on multiple rigs over the years and the Timbrens are superior by far especially because they don't leak at the connections, valves or bags or work loose. They also help with the sway.
There is no pump or electrical involved. Airbags have just too many parts and potential points of failure guaranteed to happen away from home on a muddy road. Once Timbres are installed you're done. In this case the less expensive and simpler solution is the better one!
Tom E. profile picture

Tom E.

8/9/2026

Still working great! No issues. Other than being dirty, they look and perform like new.

Jerred H. profile picture
Etrailer Expert

Jerred H.

8/9/2026

@TomE That's great to hear Tom! Thanks for coming back after a year and sharing that feedback.
by:
2012 Toyota Tundra
Time will tell! Fast and easy install on my 2012 custom flatbed tundra. Hoping this will help when I overload my truck. I have about 900 lbs of extra weight on my truck at all times + Old man Emu heavy duty leaf springs.
by:
Really won't know until I put my truck camper on the vehicle. Product looks and feels quality, we'll see about performance. Installation instructions could be a bit more detailed.
James profile picture

James

7/27/2026

So far they have been fine. They are part of my suspension upgrades, along with stable loads and sway bar. I wasnt worried about harder ride when camper off, I wanted best suspension when camper was on. I would definitely recommend them.

by:
Huge posotive difference felt when towing a fifth wheel trailer. There is still too much gap between the axle tube and the cushion, so Timbren is sending additional hardware at no charge.
by:
2006 Ford F-350 Super Duty
It was tough to remove the stock bump stops on a 06 f350 the new timbrens were straight forward easy to install. They are quite expensive for what they are! I won’t be putting the slide in camper back on until spring so I really won’t know how they will perform but I hope they work as advertised.
by:
Ford F-350 Super Duty
I ran air bags on my previous trucks when pulling my 5th wheel and trailers, but these worked just as well without the expense. I run them on a F350. Great product!!!
by:
2011 Ram 1500
The installation was pretty simple and I’m sure they will work out fine, but I won’t know for sure until the next time I have to take my tractor on the trailer or load up my ATV.
by:
2023 Ford F-350 Super Duty
The Timbrens arrived and install was a breeze. Look to be of very good quality. I went with the severe duty because my truck is always loaded up with camping supplies, electric bikes tools…. The topper on back along with the slide tray are added weight. I pull a 7k travel Trailer with 650-700 pounds on hitch. The Timbrens are barely touching the axel without the trailer. I really enjoy dealing with etrailer. They answer all your questions and always put the customer first. It’s kind of like your project is their project.
Charles profile picture

Charles

2/8/2026

Excellent product. Does exactly what they were designed to do. I removed the sever duty extension. Now the ride is soft when unloaded. But yet smooth when towing or loaded heavy.

Andrew N. profile picture
Etrailer Expert

Andrew N.

2/9/2026

@Charles Nice! I'm glad you are still enjoying them. I had the timbrens on my old Nissan Titan and they did great for the 5 years they were installed for towing my car hauler. I'm curious though, when you say you removed the severe duty extension, are you meaning the rubber spacer?
Charles profile picture

Charles

2/9/2026

@AndrewN Yes sir, with the extra rubber in the ride when empty was a little rough. IMG_6417.jpeg
by:
2016 Ram 1500
They are difficult to seat. Soapy water does nothing to help. I had to spray with silicon,jack up the back of the truck and place 2x4's between the bump stop and the axle,NUMEROUS TIMES.
Once I towed my 5th wheel I noticed the difference. When unloaded, the ride is normal.
by:
Love my Timbrens. Had airbags and was tired of leaks and the need to adjust air pressure. Easy to install!
by:
It would be helpful if the kit contained all the hardware to attach it to the truck. I purchased this to replace a Loadlifter 5000 that was installed 9 years ago. I don’t have the OEM clip and nuts that goes into the frame. It took hours of searching before I finally figured out I could find it on the Ford suspension schematics.
by:
Ram 3500
Do not keep vehicle level. 800 Lb. tongue weight trail still lowers rear of truck approximately 4 inches. 3500 GMC Dually 4x4

My advice is don't be lazy just go with air bags.

They say satisfaction guaranteed defiantly not satisfied and will be less than happy if they charge me a restocking fee on a bad product. I should have known better.
by:
My truck has an added utility body in the bed at all times. Before addinng the Enhancement System I did not feel that I had control of the truck. After adding the system the truck drives much easier and has a "safter" fee.
by:
2026 Ford F-550 Cab and Chassis
Quality product, I have owned Timbrens before. They work good. Installation is fairly easy depending on your skill level. Etrailer as always - great!
by:
2025 Ford F-450 Super Duty
The reality of how long it took to install was misrepresented. I am 74 years old and my wife and I installed these bump stops in about a 2 hour span including rest time. We actually expected that. The results were as promised and I truly appreciate that.
by:
Dodge Ram Pickup
Works very well on my Ram 3500 long box 4x4. Really helped with stability pulling a 2600# tongue weight, 16K Gvw 5th wheel. Super easy install!
Loren profile picture

Loren

3/6/2026

No changes, zero issues or regrets!

by:
Awesome. They work great. I’m glad I chose this path versus airbags.
Scott profile picture

Scott

5/9/2026

They work great and are holding up well after a year in service on my 2011 F350 SRW hauling my Lance 855 truck camper.

by:
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. profile picture

Bryan L.

12/11/2017

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.

by:
Package arrived and pretty beat up from shipping, everything was there except the hardware. I sent etrailer an email and Joy T. replied back quickly, got hardware in the mail and I installed today. Great service and quick response!
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See what our Experts say about this Timbren Vehicle Suspension

  • Purpose of L-Bracket that Comes with Timbren Suspension Kit # TFRTT1525
    Sounds like you are talking about the L-bracket that sits inside the frame that the instructions show you are supposed to route the bolt through. It's designed to distribute some of the force of the bolt that tightens down as well as brace the frame. If you don't install it you'd potentially bend the frame up. If your your current bolt isn't long enough I'd recommend finding a longer one at a hardware store. The one that came with it SHOULD be the right length though.
    view full answer...
    Image 1 for
  • 2003 Ford F-150 Timbren Suspension System Comparisons
    Usually when people use the Timbren suspension kits they talk about how great the kits work out for hauling loads or towing but a common complaint is how rough they make the unloaded ride feel so I would go with the 6K # TFR1525HD over the 7K # TFRTT1525 for your 2003 Ford F-150. With that being said, it is important to note that any suspension enhancement, whether it's the Timbrens or another solution, will not increase the weight capacity of your vehicle and is designed to help support...
    view full answer...
  • Installing Timbren Rear Axle Jounce Spring Kit TFRTT1525 in Lifted 2002 Ford F-150 4X4
    The correct Timbren rear-axle jounce spring kit for your 2002 Ford F-150 4X4 is part # TFR1525HD. The rubber springs install in place of the truck's factory bump stops with no drilling required. If your truck has a body lift you will not need any additional parts. If it has a suspension lift you will need to add spacers # A25723-90AH00, four per side, and locally source longer bolts to install the kit. This is described and shown in the linked video.
    view full answer...
  • Differences between Timbren Front Suspension Kits for 2002 Ford F-150
    The difference between the two kits is the amount of suspension support either provides. Both the part # TFRTT1525 and # TFR1525HD are a confirmed fit for your 2002 Ford F-150 but the part # TFR1525HD has the lighter capacity for and the part # TFRTT1525 has the higher capacity. This kit is intended for severe duty vehicles like tow trucks so for your application the # TFR1525HD would be a better choice. It won't be quite as harsh feeling.
    view full answer...

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Info for this part was:

Employee Tyler C
Written by:
Tyler C
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Dustin K
Video Edited:
Dustin K
Employee Chris R
Video Edited:
Chris R
Employee Steven C
Installed by:
Steven C
Employee Robert C
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