Timbren SES Suspension Enhancement System SKU# GMRTT35D - Rear Severe Service Kit
Suspension Rubber Helper Spring Kit
Each laser cut piece of steel is powder-coated to ensure a quality fit. We’ve engineered our hollow rubber springs to deliver a progressive spring rate. In other words, the more weight that pushes down on the rubber springs the harder they work to prevent rear end sag. Whether you’re pulling a trailer or carrying a heavy load in the bed of your truck, our hollow rubber springs adjust automatically to keep the vehicle level at all times.
This SES Suspension Upgrade replaces the jounce stop on the frame. Its unique design ensures superb ride quality – loaded or unloaded. (There should be a ½” to 1 ½” gap between rubber spring and axle to ensure unloaded ride quality.) Unlike other auxiliary spring systems, the SES Suspension Upgrade guarantees the best of both worlds.
GMRTT35D replaces the bumpstops on the rear suspension of the 2011-2020 GMC Sierra and Chevy Silverado 2500HD pickup truck models and 3500HD pickup truck and cab and chassis models.
We recommend Severe Service kits be used with a slide-in camper or salt spreader. In fact, any application that requires maximum stability (reducing roll and sway) calls for a Severe Service upgrade. (Click here for more info on Severe Service recommendations)
This kit is rated at 8000 lbs capacity. Even though you’re increasing the spring rate by adding this upgrade, this does not increase the GVWR (Gross Vehicle Weight Rating). Please make sure that the load does not exceed the GVWR set by the manufacturer.
Timbren SES – Suspension Enhancement System – upgrades improve your suspension with:
When extra weight makes your vehicle squat in the back, the front-end lifts up reducing traction on the front tires. Not only that, if the front is too high your headlights will shine up into the eyes of oncoming traffic instead of pointing down on the road ahead.
Timbren SES upgrades are designed to keep your vehicle level at all times. This will increase traction on the front tires, improve overall steering and keep your headlights pointing down on the road where they belong.
If extra weight makes your vehicle top-heavy, you’re going to experience body roll and sway. There’s nothing more challenging than trying to keep your vehicle moving on a straight path when the load is unstable.
Timbren SES upgrades offer you more stability and peace of mind by eliminating suspension sag and reducing body roll & sway.
Too much weight can cause your vehicle to bottom out if you’re driving over roads that are bumpy and rough. All this road shock will compromise an otherwise comfortable ride.
Improve your ride quality by installing Timbren SES upgrades, guaranteed to provide a softer, smoother ride… empty or loaded.
- Eliminate Vehicle Squatting & Sagging
- Cushion Road Shocks
- Improve Handling
- Satisfaction Guarantee
- Lifetime Warranty
- Rated for 8000lbs
- Overall kit height = 5.50”
What's Included In The Box:
- 2x Pre-Assembled Timbren SES rubber springs and mounts
"The Timbren SES system is the answer for rear end sag and soft handling." Larry V. - South Dakota
"My F-250 is awesome, now. Thanks to your Timbren SES system I don't have to worry about a 'sagging rear end'." Rick C. - New York
"I've put a Timbren SES kit on 2 different RAM 1500 trucks and would never tow anything without them ever again." Joel I. - Ontario, Canada
Timbren SES products come with a Lifetime Warranty which includes:
- Defects in material and workmanship.
- Damaged parts under normal use and service.
Warranty limitations include the following:
- Warranty applies to original purchaser.
- Warranty is not transferable to another vehicle.
- Warranty does not include labor, freight or collateral damage.
- Timbren reserves the right to inspect the failed part and ask for proof of purchase.
- Timbren will not warrant the product in the event of alteration, misuse, overload, negligence or damage cause by others.
I installed a rear kit on my pickup truck and its almost touching the axle. The installation instructions indicate that I need a 1" gap. What should I do?
Remove the rubber spacer supplied in the assembly. If you have already done this or if there is no spacer in the kit then take the vehicle out for a test drive. Often with a vehicle having a partial load, or a vehicle having an older suspension, the rubber spring may be in contact with the axle with no adverse ride quality. If ride quality is poor, contact Customer Service.
I installed a rear kit on my pickup truck and there is more than 3 inches of gap between the rubber spring and the axle. Is this ok?
Ideally, you want to adjust the rubber spring assembly to a gap of about 1 inch. In most cases this can be done with a spacer included in the kit. If you have already installed everything included with the kit, and you still have too much gap, contact Customer Service.
The capacity rating of the Timbren SES kit seems awfully high. I am sure that I do not need that much capacity for my application. What do you recommend?
The real question you seem to be asking is Will this give me a rough ride? The products progressive spring rate provides superb ride quality with any load. Also when cornering, swerving or in high wind situations, the improved stability offers great performance and peace of mind.
I'm experiencing a rough ride when my vehicle is unloaded. Can this be fixed?
If you have installed the Timbren SES (Suspension Enhancement System) and find that the vehicle ride quality is poor when empty, measure the gap between the rubber spring and the axle. (See Question and Answer #1 for further details and solutions.)
The rubber spring is touching the axle all the time. Will that hurt the axle?
Not at all. Primarily, the total weight of the vehicle normally contacts the axle at a point under the leaf springs. The rubber spring, however, contacts the axle at a secondary point of contact. By adding a secondary point of contact we are reducing the stress at the original point and are spreading out the load to 4 points of contact on the axles instead of 2.
Furthermore, the progressive spring rate provides a soft uptake of the load rather than the sudden stop of a solid bump stop, providing a good ride with reduced stress.
I have a 1985 motorhome with a badly sagging rear suspension. Will Timbren's SES (suspension enhancement system) help?
Timbren's Suspension Enhancement System will certainly help, but our systems are designed to work in conjunction with a suspension that is in good condition. We recommend that the motorhome be inspected by a suspension specialist, to ensure the suspension is in good condition, prior to installing a Timbren system.
Can I haul more weight on my truck if I install Timbren's SES kit?
You cannot exceed the manufacturers axle rating or GVW rating of the vehicle. A Timbren suspension enhancement system will greatly enhance the performance of a heavily-loaded vehicle by adding to the spring rate. You can expect reduced sag, and improved roll stability.
How does Timbren's product compare to an air system? What are the advantages?
Here are 9 ways to compare Timbren's SES to an Air Ride system:
- Ride Quality: SES upgrades deliver a softer ride empty and loaded especially with extra-heavy loads
- Stability: SES upgrades eliminate roll and sway even with the heaviest loads
- Reliability: SES upgrades are made to last they will never start leaking air because there is no compressed air.
- Ease of use: SES upgrades require zero maintenance.
- Ease of installation: SES upgrades take less than an hour to install
- Price: The installed price of an SES upgrade is about 1/2 the installed price of an air system
- Warranty: SES upgrades come with two of the best warranties in the industry
- Lifetime warranty
- Customer Satisfaction Guarantee
- Timbren SES
- Item Requires Shipping
- 6.0 lbs.
- W10.5000” x H6.0000” x L8.5000”
- Free ground shipping to lower 48 states (some exclusions may apply)
Total Reviews (1)
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Reviewed by: david03/14/2022 12:48AM
Product ownership: A year or longerNot purchased from: Timbren
I originally installed the normal duty GMRCK25 kit on my truck to tow a 36 foot fifth wheel, which was causing a severe porpoising problem. Replaced the shocks; not much help. I still felt better could be had, and contacted Timbren customer service. Very helpful, and suggested the severe service kit GMRTT35D. He asked where I purchased, and I replied Amazon. He then offered to send out a no charge kit for me to try. Unbelievable. It arrived and installed easily. Definitely the solution to the problem. Same empty ride as before with great loaded ride movement control. These are slowing down the factory leaf springs to take out the severe bounce I was experiencing. Just bought a dually, and will move these over and install the softer ones to the old truck before I sell. Much easier and more effective than air bags--install em and forget em!!