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When a heavy trailer or bed load makes the rear of your vehicle sag, the Timbren Rear Suspension Enhancement System keeps things level. The hollow rubber springs add up to 20,000 lbs of support above the rear axle, working with your factory suspension to prevent squat and maintain steady handling. With the truck level, steering, braking, and headlight aim stay consistent whether you’re hauling gear or towing a trailer.
Rough roads and heavy loads don’t have to mean a rough ride. These hollow rubber springs absorb most of the road shock and cushion bumps to create a smoother, more stable ride while loaded. They act like shock absorbers, taking the brunt of impacts and helping prevent bottoming out so your suspension components last longer and your ride stays comfortable.
The convoluted shape of each spring compresses progressively as weight increases—soft under light loads, firm under heavy ones. That means you still get normal suspension movement when empty, then solid support when you start loading up. As the springs stiffen with added weight, they keep your vehicle level and improve overall stability without requiring manual adjustments or air pressure changes.
Each spring works independently to support its side of the vehicle. That independent action reduces body roll when turning and helps keep the truck steady if one side carries more weight. You’ll notice more control when you swerve, take corners, or fight through crosswinds since sway from the trailer or uneven loads is minimized for a more planted feel on the road.
This system bolts directly to the frame above the rear axle using vehicle-specific brackets and hardware. The 1" of clearance between each spring and the axle lets your stock suspension move freely under light loads before the Timbrens step in under heavier weight. With no air lines or compressors to install, setup is straightforward and maintenance-free once in place.
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Michael: Hi there. I'm Michael with etrailer.com. Today, we're going to take a quick look at the Timbren rear suspension enhancement system. This system is designed to work with the vehicles that you see on the screen there with year range and models. It will work with your 2002 through 2020 Freightliner M2 as well as your 2009 through 2020 Freightliner Columbia. Your 2000 through 2019 Western Star 4,900 and your 1996 to 2005 Sterling L-Line L85.
So if you have one of those vehicles, obviously, you're hauling some heavy loads, some big trailers. An enhancement to your suspension system is going to do a lot of good for you. It's going to help make your ride more comfortable, help reduce some of that body roll and sway, and help to eliminate the transfer of your trailer's side to side movement to your truck. This is going to be a great option for you.These are custom brackets, so there is going to be a little bit of drilling into the frame of your truck. A little bit of welding to do but, overall, very simple installation.
Once you get that welding and drilling done, it's basically just a bolt on application. It's going to be very easy to get these installed. These are rubber springs so they're going to do a good job of absorbing a lot of road shock for you, helping to just support your suspension system on your truck. These do provide 20,000 pounds of support. Keep in mind that does not increase your load carrying capacity, sometimes confusing.
Think of it less like these are providing a second set of hands that would help you lift more. Think of them more like a back strap. They're going to support your suspension system, not to increase how much it can carry but just to make sure that it's carrying that load safely so that you have longevity of your suspension system and your overall truck.These do work independently because they are on either side. There's no connection between them. When you take a corner or big gust of wind or something pushes your truck offset, it's going to activate one and not both.
It's going to give you a lot of stability, help reduce that body roll and sway that you can often get. Because these are a rubber spring, they are going to compress gradually. If you have a light load on them, they're just going to compress a little bit but the heavier the load on there, the more they're going to compress, the stiffer they're going to get to provide more and more support for you.Overall, if you're going to be doing some over the road trucking some long distances or just have lots of heavy loads all the time, these are going to be a great option. Make the ride a lot more comfortable for you, help support your truck and just do a good job overall. That's going to complete our look for today. Again, I'm Michael with etrailer.com. Thanks for watching.
Customer Satisfaction Score:
91% were satisfied with this product
9% of customers were not satisfied
Ratings & Reviews
Christopher H.
8/14/2026
Love hearing this! Really appreciate the detailed feedback and photos. That extra stability when you're loaded up can make a huge difference. And installing them at 11 at night—that's commitment. Hope they treat you just as well on those mountain roads. Safe travels and we'll definitely make sure Dee Dee gets the shoutout.
Lazer S.
8/19/2026
Glad to hear they are working well for you, Ryan! Now that they are on, where you headed?
Jay S.
8/14/2026
Now that its been a year Im very impressed with them. Theres no ride detriment without the 5th wheel attached and they do a great job of mitigating squat
Christopher H.
9/3/2026
Happy to hear the Timbrens are making that big of a difference Tony. Thanks for including the photo and we appreciate the kind words! Have you taken any longer trips with the Timbrens installed?
Jesse M.
9/10/2026
Awesome! Glad to hear the Timbrens made such a big difference in the ride quality. Thanks for sharing! Happy travels!
Brooke M.
5/7/2025
Wow, thank you for sticking with us, Don! That is awesome. I think you made an excellent choice here. Timbrens are tough and the heavy duty are SUPER tough. Glad to hear these were a good fit. Love the photos! Is that your own property?
Don
5/21/2026
The TIMBRENs work as stated during when I am pulling anything heavy. However, when the truck is not pulling anything, anyone riding in the rear seat gets a very hard jarring jolt when driving over any roadway repairs, bumps, expansion joints on bridges. I wished that I would have went with the Super Springs, or the Road Active Suspension. I may replace the TIMBRENS later.
Gwendolyn Y.
5/21/2026
Kate F.
5/6/2026
Glad to hear the Timbren systems worked out so well for your RAM Van Mitchell! It’s great that you noticed the smoother, more progressive response compared to the factory bump stops, especially under load. Thanks for sharing your experience with both the front and rear installs, that’s really helpful for others considering the upgrade. What kind of loads are you usually hauling with your van?
Lazer S.
6/16/2026
They definitely look like they are helping, Orlando! How are they when you aren't towing? We hear a lot of people say they can be pretty harsh when unloaded.
Kate F.
7/13/2026
Bud, thank you so much for taking the time to leave a review! I'm glad to hear the suspension upgrade helped reduce the sagging and porpoising while towing. I also really appreciate you including the installation pictures and sharing your tip about removing the rear wheels. I'm sure that will help the next person tackling the install. Thanks again for choosing etrailer!
Heather A.
4/24/2026
Hi there, thanks for reaching out, that’s actually a common issue with this type of trim. The one you tried is a standard flat insert, but some RVs (like your NOBO) use a slightly domed trim to help it sit over the screw heads in the track. If the screws stick up even a little, a flat trim won’t fully snap in place, which sounds like what you’re running into. The best way to find the right replacement is to remove a small piece of your original trim, lay it flat, and measure the full width from edge to edge. Most are either 3/4" or 1", but the shape matters too, not just the width. If yours has that domed profile, you’ll want something similar or a softer vinyl that can flex over the screws. If you’re able to send a quick photo of your track or old trim, I’d be happy to help you find a better match.
Mike L.
4/23/2026
Niiiice, I see what you did there!! That looks like a sweet setup!
Mike L.
4/23/2026
Mike L.
4/2/2026
Glad to hear they worked well for you Jerrod. Hope you had a good trip!
Lazer S.
7/20/2026
Glad they are working well for you, Kevin! Well, while you are towing, that is. We have heard that these can be pretty rough when unloaded, but work great when you are loaded. A quick release function on these would make taking them off when not towing a lot easier. I may pitch that to Timbren to see if they can work something out. I will tell them to call it something like the Kevin Device if they agree! ^___^ Sounds like quite the trip! What has been your favorite stop so far?
Mike L.
2/26/2026
Thank you Darrell, we're glad to hear your Timbrens are still on the job!
Kate F.
4/23/2026
Thanks for sharing your experience Thomas. It is great to hear the Timbrens made a noticeable difference in ride quality and reduced body roll on your E350 Class C. We also appreciate the heads-up on the install. That kind of real-world feedback about brake line clearance is very helpful for others working on a similar setup. Would be nice if they had a stronger option, if you need the 5K, might need to go to airbags, but who wants to deal with having to air up if you don't need to. Where are you off to on the next adventure?
Mike L.
7/7/2026
Nice setup David, thanks for the photo!
Kate F.
5/6/2026
Glad we had the right suspension upgrade to help with the squat Dennis! How is the ride when you are unloaded?
Kate F.
8/31/2026
With the Timbrens, you will want to have a 1/2" to 1-1/2" gap when the vehicle is unloaded. They are only designed to engage when the suspension is under load and you need the additional support. If you want to reduce that gap so the Timbrens engage sooner, you can add the 1/2" Spacer # TA25722-90P00 or the 1" Spacer # A25723-90AH00.
Kate F.
8/31/2026
I am happy to see we had some suspension support for you Benjamin! What kind of trailer are you towing?
Heather A.
2/21/2025
Timbrens are the best for sag because they are made of dense rubber. 6500 lbs sounds like one heck of a travel trailer, what is it? Any fun plans this summer?
Jerome
3/2/2026
Awesome product. Would recommend.
James D.
7/24/2026
We're glad to hear the Timbren suspension system is already making a difference. We'd love to hear how it performs over time. What are you using your vehicle for most often; towing, hauling, or everyday driving? Thanks for your review and we appreciate you choosing etrailer!
Claire H.
7/14/2026
Wow! That is quite a difference between your factory bump stop and the Timbrens! Definitely let us know how they perform for you!
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Robin H.
9/22/2026
Thanks for taking the time to share such a detailed review and all of the pictures! The unloaded ride is a concern we hear fairly often with SES upgrades, so your experience with the 1" gap and rough-road testing will be really helpful to others considering these for their F-250. We appreciate the kind words about Naomi and our team as well. Looking forward to your update once you get some miles on them with the Rockwood!