1. Vehicle Suspension
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  4. Rear Axle Suspension Enhancement
  5. Standard Duty
Timbren Rear Suspension Enhancement System

Timbren Rear Suspension Enhancement System

Item # TFREXC4
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Timbren Rear Axle Suspension Enhancement - TFREXC4
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6,000-lb Capacity. These hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. They also provide a more comfortable ride by absorbing road shock and improving roll stability. Easy to install and use. Lowest Prices for the best vehicle suspension from Timbren. Timbren Rear Suspension Enhancement System part number TFREXC4 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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  • Reviews (1964)
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Timbren Vehicle Suspension - TFREXC4

  • Timbren
  • Jounce-Style Springs
  • Rear Axle Suspension Enhancement
  • Standard Duty

6,000-lb Capacity. These hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. They also provide a more comfortable ride by absorbing road shock and improving roll stability. Easy to install and use.


  • 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
      • Does not affect the empty ride of the vehicle
    • 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: 6,000 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

Reduced rear axle sag with Timbren suspension enhancement

Whether you're hauling heavy loads in your bed or cargo area or 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 your rear axle. Hollow rubber springs are bolted to the bottom of the bracket and hang down to where the bottom of the leaf 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.

Action 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.

Trailer swaying as it is towed behind a truck

Because your 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 SES

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.

FREXC4 - Rear Suspension Enhancement System with Aeon Hollow Rubber Springs by Timbren

Installation Details TFREXC4 Installation instructions

This Product Fits The Following Vehicles

Video of Timbren Rear Suspension Enhancement System

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Timbren Front and Rear Suspension Enhancement Systems Review

Speaker 1: Today we're going to be taking a look at the Timbren line of suspension enhancement systems. Any time that we add weight to our vehicle, it's going to put a lot of strain and stress on the suspension, especially if we're towing a heavy camper, trailer, or we have a heavy load in the back.Tends to have the back end squat down, which again, it's going to put that strain and stress on the rear suspension because not only are we asking it to hold up the weight of the vehicle, but everything else that we add on to it. Which that can arise a lot of different issues. The front end is going to be getting pulled off, which will misalign our headlights, and our tires won't have as much contact, so our steering and braking is going to be diminished.But tat;s where timbrens are going to come into play. They're going to provide us that extra support so that when we do have those heavy loads, the back end doesn't sag down quite as much, and it's not putting so much stress on the back end. By doing that, the front end's not going to rise up, which means our headlights will be in line and our tires will have the correct amount of contact and pressure, so our braking and steering isn't affected.

And they're going to do that all while making our ride more comfortable with that extra load.Our timbrens are going to provide us the support we need by replacing our factory jump stops and mounting in between the frame and the axle. Now, yours may look different, so you want to double check inaudible 00:01:20 fit guide for your specific application.Now, each one of our timbrens is going to feature a steel bracket. They're all going to have black, powder coat finish on them to resist that rust and corrosion or any other kind of chemicals that may be on the road. They're going to have a hollow, rubber ayon 00:01:36 spring that's going to take a lot of that pressure and strain off of the rear suspension.Whenever we do load our vehicle down, the space between our frame and our axle is going to get smaller. That's where our spring is going to make contact with the axle, and it's going to start compressing.

Now, they are progressively rated, so if we have a small load or a light load, it's going to have a little soft engagement. But the further it gets compressed, the harder and stiffer it becomes, giving us the support we need with those heavy loads.And since they are rubber, they're going to have a lot of give to them, which means they're going to give us the support we need. But at the same time, they're going to give us some more cushion and absorb some of the road shock as we drive. And since the rear ones here aren't in constant contact with our aXle, it is going to provide us the same ride quality when it's unloaded.Our timbrens are going to work independently from each other from side to side. That way, if we have an off center load, it will help compensate for that, but at the same time, if we take an evasive maneuver or a really sharp turn, this is going to help reduce that body roll and some of that sway feeling that we get going on when we have a lot of added weight.Our timbrens for the rear are going to be a good enhancement for any time you're going to be adding weight to the back of your vehicle, whether it be a heavy trailer, a large load in the back or any other situation where you're adding a lot of weight to the back of your vehicle.Now, timbrens on the front are going to be a little bit different.

They're going to provide us that load-leveling support and make sure the front end doesn't get pushed down too far. However, these typically are going to be in contact all the time, which means it's going to give us that support and help reduce on that body roll all the time, all while absorbing that road shock, giving us a smoother ride.Now, some situations where you'd want that extra support on the front of the vehicle to keep it from getting pushed down too much would be if you have a snow plow or winch, if you flat-tow your vehicle, or if you have any other heavy accessory on the front. This is going to make sure that front end stays where it should be, and again, making sure our tires, braking and steering acts how they should.When comparing the timbrens to other suspension enhancement options like airbags, these are going to be a lot easier to install because we're not going to have to worry about running lines, maintaining air pressure, putting in switches or compressors or any of that. Once these are installed, these are going to be completely maintenance free. However, airbags are going to provide us with a lot more adjustability, whereas our timbrens are not going to have that.That'll finish up your look at the timbrens suspension enhancement systems..

Customer Reviews

Timbren Rear Suspension Enhancement System - TFREXC4

Average Customer Rating:  4.7 out of 5 stars   (1964 Customer Reviews)

6,000-lb Capacity. These hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. They also provide a more comfortable ride by absorbing road shock and improving roll stability. Easy to install and use.

2000 Ford Excursion

Installed on 2000 Ford Excursion to keep rearend from sagging when towing 24' Thompson 240 Fisherman Hardtop Boat. Worked like a charm once I got the stock bumpers off. Had to get the [$] [discount store] 4" Grinder out to remove stock bumpers. Works great, so far - just like described. Bumpers remain hanging in air with no contact until a heavy load is applied inside Excursion or on trailer hitch. Excursion remains essentially level with Thompson Boat/Trailer hitched-up. 364340

2001 Ford Excursion

Product installed very easily, spacing seems a bit much from the bottom of the product to the axle, but that could just be me. Nothing against you guys, but the package was delivered VERY damaged, some of the contents were showing outside the box. 64729

There should be a sizeable gap between the Timbren springs and the vehicle axle. The Timbren kit should only engage the axle when the vehicle is bearing a hefty load. This is to prevent un-loaded ride quality from being altered, but provide extra support when a heavy load is in the mix.
-- Patrick B - 02/01/2013



Eliminated rear end sag when towing and also stabilized the rear improving drivability. Highly recommend. 707741

Ford Excursion

Kit does a great job making up for the underbuilt suspension on my excursion. Installation was straight forward although a bit awkward from under the truck in the driveway. The price is way high for some rubber and bolts, but that's apparently from the manufacturer as opposed to etrailer. Good product, just a shame to pay so much to make up for ford's known shortcoming. 566140

2002 Ford Excursion

installed in about 30 min. worked as expected. installed in about 30 min. worked as exspected 87099

- TFRTT1504E

Review from a similar Timbren Aeon Spring System in Vehicle Suspension

Timbren Suspension Enhancement System - Rear Axle Item # TFRTT1504E Just had a chance to install the Timbren. Went on a short drive with no load and have not hooked up the trailer yet. About an hour to install, the instructions where not very good but going on line etrailer site and followed the video. Very good product! 734943

- TFR1504D

Review from a similar Timbren Aeon Spring System in Vehicle Suspension

This was so easy to install, you DO NOT need to take rear tires off.. 60 Minute install. I went without the additional spacer to allow for a little nicer ride when empty. Very well made 730169


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

The product first arrived in a damaged box with one of the washers missing, but ETrailer did resupply that. The hardest part was finding a shop able (needs the right tools to depress coil springs) and willing (a potential liability issue messing with suspension) to replace it for a reasonable cost. Eventually a local tire shop agreed to. This was for a 2014 Honda Odyssey, especially for pulling a pop-up. Took two camping trips last summer, one before and one after installation, and I have been pleased with the added stiffness in the rear suspension. It made about 1 to 1.5 inch of difference in resting position when fully loaded and towing and has helped smooth out bumps and humps in the road - both when towing and not. 589641

Took a couple more trips this year, and its all still working good, but I found out there still is a limit to how much weight you can pack on the rear axle. Dont recommend using a double hitch extender for bike rack plus towing because it spans the tongue weight too great of a distance from the van and gets too close to the ground. This is as much a comment on not overloading the suspension as it is on the DrawTite hitch I got on etrailer.
Dan O - 12/11/2019



Review from a similar Timbren Aeon Spring System in Vehicle Suspension

I installed the Timbren Aeon Spring System Vehicle Suspension a year ago. It took about 20 minutes to do the whole installation. I'm really impressed with the overall construction. It didn't negatively impact the ride and I can now put anything I want in the bed of the truck, while hauling a travel trailer, with no concerns. 737144


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

Makes a huge difference in carrying heavy loads. I could tell an immediate difference when I had a full bed, gooseneck load, or a bumper pull load. Highly recommended. I considered air suspension, but did not want to tackle that installation. Literally can install this with a torque wrench and impact wrench. 725228

- TDF25004B

Review from a similar Timbren Aeon Spring System in Vehicle Suspension

Bought these because I just put a plow on my truck and I didn't want to mess with air bags or heavy duty springs that would raise the front of my truck. These suspension enhansment bumpers are extremely easy to install, fit perfectly and do exactly as they advertise.. couldn't be happier 726518


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

What a difference made the truck handle better and the front end is so much stronger 727838


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

These things work great. You never have to worry about air leaks or the air pressure like you do when you have bags. 601205

They are still working great.
Harold - 01/30/2020


- TDR2500D

Review from a similar Timbren Aeon Spring System in Vehicle Suspension

Extremely simple install! The package was shipped quickly and arrived in perfect condition. The removal of the OEM bump stops and installation of these new ones took less than 15 minutes. All required hardware was supplied to use in concert with the existing OEM hardware. The day after I installed the new Timbren bump stops on our 2015 Ram 2500, I loaded my 24 foot trailer with cattle (weight was around 14,500lbs) and drove 120 miles. These new bump stops made a world of difference in the stability and control of my vehicle. Highly recommend this upgrade to anyone looking for some additional towing stability. 726338


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

The product worked out great... Did exactly what I needed it to do...Easy to put on.. 370797


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

This is the 3rd time I have purchased the Timbren Rear Suspension Enhancement System. I have always been satisfied with the ease of installation and the effectiveness of these springs, whether I am pulling a tow behind trailer, a 5th wheel or carrying a load in my truck. The only thing I did different this time is I purchased the Timbren Rear Suspension Enhancement System with the TorkLift StableLoad Rear Suspension Upgrade. I will post a review on the complete purchase once I install these in addition to the Timbren Rear Suspension Enhancement System. 670260


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

Sold vehicle shortly after install,never got a chance to use it. But the install was very easy and product was high quality. 636794


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

We ordered the bump guards for my handicapped transfer van. I have a power wheelchair that weighs three hundred pounds without anybody in it, with my body weight we are pushing five hundred. This additional weight was killing the suspension of the van. These news guards raised the body, tightening the suspension and made for a safer and more comfortable ride. They prolonged the life of the van as well. 721063

- TDR1500DS

Review from a similar Timbren Aeon Spring System in Vehicle Suspension

Works perfectly, easy install. Will be making another purchase for other trucks now that we were able to see how well they worked. 702944

- TFRTT1504E

Review from a similar Timbren Aeon Spring System in Vehicle Suspension

I will write a review as soon as they are installed. They came through as advertised the quality was above my expectation. I am looking forward to testing them with my boat in tow. 578110


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

As far as keeping the rear from drooping it works good. The only negative is that the truck rides a little rougher, it doesn't have as much play when hitting bumps. 488947


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

2001 F350 with a 30' heavy gooseneck camper. Major improvement. The only downside is, since my springs are older and sag a bit from factory, unloaded ride is uncomfortable since it doesn't have a gap. Only use it for pulling so it's okay. 682879


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

I recently ordered and installed this suspension enhancement for my 2017 Nissan Titan SV 2WD, Crew Cab. I will be road testing it next week with a heavy duty 20' flat trailer, carrying a 2,800 lb car, 500 lb 4 wheeler and misc items for an estimated total of near 6.5-7k lbs of trailer weight. In addition, I might be carrying a 450 lb go-kart in the truck bed. I feel this will be a good test of the products' capability and performance. Approximately 2 weeks ago, I towed an 8.5' x 20' cargo trailer weighing out at nearly 9k lbs on the same 500 mile trip. For that trip, I had the stock suspension setup and used a weight distribution (WD) system. The trip went smoothly, but I'm hoping that this suspension enhancement will eliminate the need to go through the WD hookup process. A followup review to come. I've given this a 5 star review due to the excellent customer service I received from Ashley. I was traveling back down to Florida from up north and had questions regarding compatibility with my truck. She called the company, Timbren, to verify that it would work and answered all my questions, since I was driving at the time. She even pushed the order through quickly and got it out that same day. I was amazed when I received it yesterday, less than 2 days after I ordered it and installed it in less than an hour. This is truly an example of the excellent level of customer care that etrailer provides its patrons and exactly why they are my first choice for all my trailering needs. Thank you. 725798


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

Towing our 15 thousand pound fifth wheel is way better since i installed these. Highly recommend over the the ride. Easy install. Fuctional affordable. Great product 500554


Review from a similar Timbren Aeon Spring System in Vehicle Suspension

I installed them on my truck yesterday. Very simple to put in. Won't be able to see how well they work until I hook up our 5th wheel next for a trip. 576508

Show More Reviews

Ask the Experts about this Timbren Vehicle Suspension

  • 2005 Ford Excursion Squats when Using Husky Weight Distribution with 9,000 Pound Trailer
    Let's first look at the numbers. A trailer weighing 9,000 pounds will have a tongue weight in the neighborhood of 900 to 1,350 pounds. But when you calculate tongue weight for weight distribution you also have to factory in the weight of any cargo loaded behind the rear axle of your 2005 Ford Excursion. So for example if your trailer's tongue weight is 1,100 pounds and you have 200 pounds of cargo behind the rear axle of the Excursion the total tongue weight would be 1,300 pounds and...
    view full answer...
  • Troubleshooting Trailer Sway on 11,700 lb Trailer with 900 lb Tongue Weight
    If you are getting persistent sway from your towing setup the issue is more than likely not enough tongue weight in the trailer relative to the total trailer weight. Not having the tongue weight of the trailer between 10 and 15 percent of the total trailer weight is the number one cause of trailer sway. Since you said your trailer weighs 11,700 lbs and your tongue weight is roughly 900 lbs that would be the issue right there. If you can move more weight in the trailer forward you will...
    view full answer...
  • Comparing Timbren and SumoSpring Rear Helper Springs for a 2000 Ford Excursion
    If it were me I would install the Timbren springs # TFREXC4 on the 2000 Ford Excursion 4x4 instead of the SumoSprings # SSR-109-40. First is the cost benefit; the Timbren springs cost less. There is also the capacity difference. The Timbren springs are rated up to 6,000 pounds whereas the SumoSprings are rated up to 1,000 pounds. While neither increases the actual towing capacity of the vehicle the fact that the Timbren springs are rated so much higher is an indication of the quality...
    view full answer...
  • Timbren Suspension Enhancement for the Front and Rear of a 2001 Ford Excursion 4x4 7.3L Diesel
    The Timbren Rear Suspension Enhancement System, item # TFREXC4, is only the rear kit for your 2001 Excursion 4x4. For the front suspension you will need the Timbren Front Suspension Enhancement System, item # TFF350SD4. These front suspension helpers will definitely help with the large 7.3L motor in your Excursion. Both of these kits will require the removal of the original bump stop but will not require shock or spring removal and do not require any modifications to the original...
    view full answer...
  • Height of Timbren Rear Suspension Enhancement # TFREXC4 for 2002 Ford Excursion V10
    The Timbren Rear Suspension Enhancement # TFREXC4 for your 2002 Ford Excursion that you referenced has an overall height of 5 inches according to my technical contact at Timbren. I pulled a set of these from the warehouse and measured them as you will see in the picture, the actual spring measures 5 inches and the bracket measures 1-9/16 inch to give you a total of 6-9/16 inches. The difference between a Timbren suspension system and an air bag system, is that the air setup allows for...
    view full answer...
  • Weight Distribution Recommendation for a 9,000 Pound Trailer and 2000 Ford Excursion
    Pro Series Weight Distribution System w/ Friction Sway Control - Round - 10,000 lbs GTW, 750 lbs TW # PS49902 is very much under rated for the tongue weight of your trailer. Considering that your measured tongue weight is 1,044 without water and other things even the 1,200 pound system # PS49904 might not be enough once loaded and ready to tow. I recommend going to a 1,500 pound system such as Curt Weight Distribution System # C17333. The only other part needed is a ball. The ball you...
    view full answer...
  • Timbren Suspension Enhancement For 2001 Ford Excursion
    The Timbren Suspension Enhancement, part # TFF350SD4, is intended to assist the front suspension you have on your 2001 Ford Excursion. This kit is for 4-wheel vehicles. Suspension enhancement is intended to be used on vehicles with suspension that is in good working condition. It is not intended to be used as a replacement for your suspension. I pulled one of these from our warehouse and took a couple of measurements. The spring measures 3-3/4 inches and the plate it is attached to...
    view full answer...
  • Timbren Front Suspension Enhancement That Fits 2WD and 4WD 2003 Ford Excursion
    Yes, you are on the money with the fits. The Timbren Front Suspension Enhancement System # TFF350SD2 is a fit for the 2-wheel drive model of the 2003 Ford Excursion, while the Timbren Front Suspension Enhancement System # TFF350SD4 is a fit for the 4-wheel drive model of '03 Excursion. I have added a link to a video review of this suspension enhancement for you to check out. I do want to add that if you were looking for the rear suspension units from Timbren for your Excursion,...
    view full answer...

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Info for this part was:

Expert Research:
Robert G
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
Lori W
Video Edited:
Jacob T
Updated by:
Mary E
Video by:
Jonathan Y
Installed by:
Robert C

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