Review of the Timbren Suspension Enhancement System

Timbren SES - Truck Camper Adventure

Without a doubt, rear sag and sway are the most common suspension issues for trucks hauling truck campers. Rear sag occurs when a truck is either over matched or when a truck is hauling a load near its max load rating or payload. Not only does rear sag look bad, but it can make a truck wallow in turns, and feel light when steering. Fortunately, most pickups are engineered with a nose-down rake to offset heavy loads, but rear sag can still happen. The other big issue, sway, occurs most commonly on curves or when making sharp turns. You know a truck has it if it feels like it’s going to roll or tip over when steering. The sensation can be quite unnerving, especially on winding mountain roads with steep grades. Fortunately, there are a handful of aftermarket upgrades that can be purchased to resolve these troublesome suspension issues. One of the better ones in today’s market, and the focus of this review, is the Suspension Enhancement System (SES) by Timbren Industries.

If you’re not familiar with Timbren’s SES, its pretty neat. It consists of two SES rubber spring assemblies that are mounted in place of the jounce bumpers that came with your truck. These Canadian-made springs sit about an inch above the rear axle unloaded. When your truck camper is loaded, the SES springs engage your axle. As you drive, the rubber springs expand and contract, providing your rig with proper load support. Timbren also makes an SES Severe Service kit for hauling extra heavy loads like truck campers. This is what I installed on my truck, a 2013 Ram 3500. Unlike the regular SES kit, the Severe Service kit is designed to rest on your axle in an unloaded state in order to provide maximum load support for your truck. The Timbren’s Severe Service kit can support up to a whopping 8,000 pounds, a full 3,000 pounds more than the typical air bag system.

The heart of the Timbren SES is the patented Aeon rubber spring. You’ll find a pair of these hollow rubber springs in every SES kit you buy. The company has a saying that their Aeon springs are “stronger than steel, more reliable than air,” and there’s a ring of truth to these words. Timbren’s Aeon springs will neither rust nor will they leak. Indeed, many of Timbren’s Aeon springs are still going strong after 30 years of service. In fact, all SES kits come with a lifetime warranty for as long as you own your truck. The number of Aeon springs found in each kit varies. When space between the axle and frame is limited or when extra support is needed, a single convoluted rubber spring is used. Conversely, when space between the axle and frame is plentiful or when a better ride is desired, the taller double convoluted Aeon spring is used instead. If you’re hauling a truck camper you’ll want to get the Severe Service kit with the single convoluted springs. Compared to the double convoluted springs, the single springs allow for less travel and delivers more load support for truck campers.

timbren ses - Truck Camper Adventure

Installation of the Timbren SES kit was extremely fast and easy. In fact, I’d have to say it was one of the easiest modifications I’ve ever made to my truck and camper. To perform the swap out, all you need to do is crawl under the truck, remove the two OEM hex screws that hold the jounce stops in place, and install the SES springs using the same OEM screws. Contrary to the installation instructions, I had plenty of room between the axle and frame to install my SES springs, so lifting my truck wasn’t necessary. You’ll need a socket wrench with an 6-inch extension to mount the springs to the brackets and you’ll want to place the brackets in a vise during assembly so that sufficient torque can be created to fully seat the screws into the brackets. In order to improve axle articulation and maintain the stock ride, I modified my SES springs by removing the 1-inch rubber spacer so that the springs come in contact with the axle only when the truck camper is loaded. This extra 1-inch allows for more axle movement and articulation off-road and that’s a good thing. In all, the entire installation took 45 minutes, tops.

Timbren SES - Truck Camper Adventure
The OEM Jounce Bumper (left) and Timbren SES Severe Service spring.
Timbren SES Severe Service - Ram 3500 - Truck Camper Adventure
Driver side unloaded Timbren SES Severe Service spring.
Timbren SES Severe Service - Ram 3500 - Truck Camper Adventure
Engaged (loaded) driver side Timbren SES Severe Service spring.

How well does the Timbren SES work? How effective does it eliminate rear sag and sway? Exceptionally well. In order to put the Timbrens through an effective test, I removed my rear sway bar and I have to say that the Timbrens perform just as well if not better in eliminating sway. The big negative with a rear sway bar is that one end has to be disconnected to allow the rear axle to freely articulate when driving off-road. No such adjustments are necessary with the Timbren SES. Just install it and forget about it. What about rear sag? Honestly, I didn’t have much to begin with, but what little I had is all but gone now. One of the biggest benefits that I’ve been able to derive from the Timbren SES is a smoother, better ride off-road. I no longer bottom out when hitting surprise bumps and holes and that alone is worth the investment in that it protects my rig from damaging shocks and vibrations.

Is the Timbren SES better than the traditional air bag system in addressing rear sag and sway? I wouldn’t say that one works better than the other. However, I will say this. Having owned both, I prefer the simplicity and durability of the Timbren SES. Sure, air bags are adjustable, but they’re also more complex, prone to leaking, and aren’t particularly suitable for extreme off-roading. The Timbren SES, on the other hand, excels on all types of road surfaces and doesn’t require any maintenance, adjustments, or pressure checks. Are there any negatives associated with the Timbren SES? Just one. Bumps and imperfections in the road are felt a bit more when the springs are engaged, but that’s the price you pay for resolving handling issues that put your rig at risk. To me, it’s a fair trade off. What would I rate the Timbren SES? Using a five star rating system, I’d give the Timbren SES a rating of five stars. Timbren’s SES is a suspension modification winner!

Note: This is an independent review. I do NOT get paid to review products on this website. I will only recommend products which I use and believe in and which I think will benefit my audience. The views expressed are my personal views and are written without any influence, whatsoever. That said, I reserve the right to engage in paid affiliate marketing and promotion with brands, companies and individuals whose products I review. 

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About Mello Mike 298 Articles
Mello Mike is an Arizona native, author, and the founder of Truck Camper Adventure Magazine. He's been RV'ing since 2002, is a truck camper and Jeep enthusiast, and has owned and restored several Airstream travel trailers. He enjoys college football, hiking, travel, off-roading, photography, and fishing. He retired from the U.S. Navy in 2004 as a CWO3 after 24 years and now works as a project manager for a major banking and security firm. He also does some RV consulting and RV inspections on the side.

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