bing tracking image
  1. Vehicle Suspension
  2. RAS
  3. Leaf Springs
  4. Rear Axle Suspension Enhancement
  5. Standard Duty
RoadActive Suspension Custom Leaf Spring Enhancement Kit

RoadActive Suspension Custom Leaf Spring Enhancement Kit

Item # RAS4611
Our Price: $539.00
You Save: $356.85
Vehicle Suspension

Will this fit?

To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.

Shipping Weight: 27 lbs
Add to cart
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Customer Photos

Need help with installation?
Locate installers near me
2,000-lb Capacity. Convert your vehicle's leaf springs into a mechanically active suspension system. RAS adjusts to your load to level your ride. The system also increases stability, handling, and control by improving traction and reducing sway. Great Prices for the best vehicle suspension from RAS. RoadActive Suspension Custom Leaf Spring Enhancement Kit part number RAS4611 can be ordered online at or call 1-800-940-8924 for expert service.
  • All Info
  • Reviews (690)
  • Q & A (0)
  • Photos

RAS Vehicle Suspension - RAS4611

  • Leaf Springs
  • Rear Axle Suspension Enhancement
  • Standard Duty
  • RAS

2,000-lb Capacity. Convert your vehicle's leaf springs into a mechanically active suspension system. RAS adjusts to your load to level your ride. The system also increases stability, handling, and control by improving traction and reducing sway.


  • Custom kit converts your vehicle's factory leaf springs into a mechanically active suspension system
    • Actively strengthens leaf springs for improved ride quality with or without a load
  • All-in-one suspension system improves stability, handling, and control
    • Eliminates axle wrap, wheel hop, and bottoming out
    • Reduces dangerous sway and body roll while cornering
    • Keeps your ride level when towing or hauling a heavy load
    • Improves traction while breaking and accelerating
  • Variable-rated coil tension springs automatically adjust to your vehicle's load
    • Activate immediately to support the extra weight
    • Disengage when unloaded, allowing your leaf springs to perform as intended
  • Customizable coil springs can be adjusted during installation to accommodate your towing or hauling needs
    • Independently adjustable for side-to-side leveling of off-center loads
  • Helps extend the life of leaf springs, shock absorbers, shackles, and even tires
  • Durable, epoxy e-coated steel construction
    • Corrosion-resistant brackets on the ends of each unit have a salt spray rating of more than 800 hours
  • Easy, bolt-on installation - no drilling, cutting, or welding required
    • Unit secures under the leaf spring and around the factory U-bolts
    • Fully assembled kit and hardware are included
  • Maintenance-free - adjustments and monitoring aren't needed once installed
  • Made in the USA


  • Weight capacity: 2,000 lbs
    • RoadActive Suspension will not increase your vehicle's weight-carrying capacity
  • 5-Year warranty
  • 30-Day money-back guarantee

All-In-One Suspension System

When towing or hauling a heavy load, you may encounter a number of problems that can make your driving experience difficult or dangerous, such as sway, body roll, or bottoming out. When your vehicle is weighted down, your factory leaf springs can't counteract these problems to the extent that they are supposed to. The weight will overpower the leaf springs and cause them to twist or flatten out. When that happens, they cannot support, level, or stabilize your vehicle effectively. Additionally, because your factory leaf springs are passive, they won't begin to tackle problems such as sway until those problems have already started.

Diagram of RAS Installed

RoadActive Suspension (RAS) kits enhance those passive leaf springs by converting them into a mechanically active, all-in-one suspension system. RAS kits have variable-rated coil tension springs that automatically adjust to your heavy load. Other suspension systems only solve a few problems and usually at the expense of other improvements your factory leaf springs may need. RAS, on the other hand, is a unique kit that provides everything you want in a suspension system without any trade-offs. It eliminates bottoming out like air springs, reduces sway and body roll like sway bars, keeps your ride level like helper springs, and improves traction and braking control like traction bars. This improves your vehicle's stability, handling, and control while you are towing or hauling, as well as when your vehicle is unloaded. RAS also makes your overall driving and towing experience safer and more comfortable, which greatly lessens driver fatigue.

How RAS Works

Close-Up of RAS Tension Spring

Each RAS unit has a powerful variable-rated coil tension spring that converts your passive leaf spring into a mechanically-active system. Once your vehicle is loaded, the tension springs immediately activate to absorb and support the weight. This allows your leaf springs to maintain their bowed position and keeps them from flattening out or flipping over, which greatly hinders their ability to bear a heavy load. The tension springs are variable-rated, which means that the heavier your load is, the more assistance they provide to your leaf springs. Because of this design, RAS reacts instantaneously, whereas hydraulics, air springs, and other suspension systems take time to react. And unlike your factory leaf springs, RAS stops sway and sag before they even start to happen. Additionally, when your vehicle is unloaded, the tension springs disengage, allowing your leaf springs to perform as intended without hardening your ride. RAS won't hinder your leaf springs' movement, nor will it cause any friction between any of the brackets.

Eliminates Axle Wrap and Wheel Hop

RAS Eliminates Axle Wrap

When under a heavy load, leaf springs are especially susceptible to axle wrap, which can cause wheel hop. Wheel hop is when the tires lose their grip on the road, causing a jarring, up-and-down movement. Axle wrap occurs when the circular motion of the tires cause the leaf springs to twist or rotate. If the leaf springs twist far enough, wheel hop can occur. RAS stabilizes your leaf springs by absorbing the force of the load they're trying to support. This eliminates axle wrap and wheel hop, as well as prevents your vehicle from bottoming out. Because of this, less strain is put on your vehicle. And by reducing some of this wear and tear, RAS helps extend the life of your leaf springs, shock absorbers, shackles, and even tires.

Reduces Sway and Body Roll

RAS eliminates sway and body roll

When driving along a curve while towing or hauling a heavy load, the back end of your vehicle or trailer can start to shift with that weight. If your factory leaf springs have flattened or twisted under this load, they won't be able to prevent it from shifting. Because of this, your trailer will sway away from your vehicle. This makes driving challenging and dangerous, as it increases the risk of body roll, which is when your vehicle drastically leans to one side. This can often cause you to completely lose control of your vehicle. Body roll is especially prevalent with multi-passenger vans and vehicles towing long campers, trailers, or boats. RAS provides a much safer ride by reinforcing your factory leaf springs and stabilizing your load. This helps prevent sway from occurring and reduces the chance of body roll while cornering, turning, and swerving. RAS also lessens the rocking motion that happens during windy conditions or when a semi passes by on the road.

Levels Your Ride and Improves Traction

RAS Levels Your Ride

When your vehicle is overloaded, the bulk of the weight transfers to the rear axle. Your factory leaf springs then become overwhelmed by this weight, as they are not strong enough to support it. This causes the back end of your vehicle to sag and the front end to rise, which means that the front tires have lost some of the grip they need with the road. In addition to loss of traction, it can also cause poor headlight aim, unintentional swerving, and an extremely bumpy and uncomfortable ride. RAS bolsters your factory leaf springs and enables them to provide support for your load without compromising ride quality or comfort. This keeps your ride level from front to back whether you are hauling a load in the bed or towing a boat, trailer, or camper. RAS also ensures that your tires have the traction they require while braking and accelerating, which improves the overall driving experience.

Customizable Coil Tension Springs

Adjusting Spring With Spacer

RAS is also customizable. During installation, the coil tension springs can be adjusted to 2 different tension settings or anywhere in between for improved road handling and support. To do this, rotate the springs while keeping the threaded rod still. As you turn the spring, use one of the 2 included spacers as a gauge to measure the widening gaps between the coils. In order for the RAS units to work as intended, you must tension the coils to a minimum of 25 percent with the 1mm white spacer and no more than 40 percent with the 2mm spacer. The springs can also be independently adjusted to compensate for off-center loads such as a handicap lift.

Easy, Bolt-On Installation

RAS Once Installed

This custom-fit kit comes fully assembled and is easy to install. Each RAS unit simply bolts onto your factory leaf spring with the included hardware, and drilling, welding, and cutting aren't required. First, position the eye hook bracket so that it wraps around the top of the factory leaf spring eye. Then the axle bracket secures under the leaf spring and around the factory U-bolts on the other side of the leaf spring pack. Once the maintenance-free RAS units are fully installed, you won't need to monitor them as you would with air springs.

Corrosion-Resistant Steel Construction

RAS Construction Close-Up

RAS is extremely durable and corrosion-resistant. The units are constructed of high-grade alloy steel, and they have an epoxy e-coat on the coil springs to provide extreme corrosion resistance. The brackets on the ends of each unit resist the effects of water and other elements, and they have a salt spray rating of more than 800 hours.

4611 RAS Custom Active Suspension System for OEM Leaf Springs - Rear Axle

Installation Details RAS4611 Installation instructions

This Product Fits The Following Vehicles

Customer Satisfaction Score:

Customer Reviews

RoadActive Suspension Custom Leaf Spring Enhancement Kit - RAS4611

Average Customer Rating:  4.7 out of 5 stars   (690 Customer Reviews)

2,000-lb Capacity. Convert your vehicle's leaf springs into a mechanically active suspension system. RAS adjusts to your load to level your ride. The system also increases stability, handling, and control by improving traction and reducing sway.


Overall, very happy with the product. GMC didn't have any way to improve the truck from squatting when I hooked up my trailer. This kit didn't stop the squatting but significantly reduced the bounce on bad dips in roads, bridge/road transitions and bad railroad crossings.



Removed the Suspension Enhancement and installed Airlift. Cost more but rear-end isnt sagging 4.

2021 Chevrolet Silverado

This system allows OEM ride in my 21 Silverado Z71 when a trailer is not being pulled. I have pulled an 8000 lb work trailer, and a 5000 lb travel trailer, with barely noticeable squat of the truck. This kit really seems to stabilize the back end when pulling a trailer. I'm very pleased.



It still performs as advertised. Another benefit I have noticed is steering stability. The back end is not squatted down to where the front wheels are lighter on the pavement. Ive had many comments from my crew about it.


I have a 2020 Silverado 1500 6 cyl Duramax with the Diesel Off Road package (3.73 diff). Travel trailer loaded is probably about 6,000 lb. I took several measurements during and after the spring kit installation. All measurements increased about an inch including the stock suspension with trailer and equalizer bars and with the spring kit installed at 1 mm spacing. A one inch improvement overall. I took the truck on a short drive and didn't notice any difference in ride (wasn't stiffer) which is what I wanted. Good to know that I can adjust the springs to the 2 mm spacing if I want to increase the suspension assist. Going camping next week and looking forward to see how it improves handling and porpoising.

Rick M.


After a year I am still pleased with this product. I had been adjusting the spring tension higher when towing and then back down after a trailering trip, but now just leave it adjusted to the trailer towing tension as the unloaded ride doesnt seem to suffer when the springs are tighter.


The product does what it is advertised for its a little challenging to install by yourself but it definitional illuminated my squat issues when towing my boat and double axle trailer.

Chevrolet Silverado

This is the second time I have installed these. I wouldn't be without them. They do do stiffen the ride a bit when I am running empty but it's not bad. Huge improvement when towing, the truck feels much more stable.Installation is straightforward,I spent more time jacking up the truck and removing the wheels than installing the springs. Installed on 2023 Chevy Silverado 1500.

2007 Nissan Leaf

The RAS arrived on time and was super easy to install. It took my son and I about 45 minutes to install. It helps when you have all the right tools handy. The only thing I didn’t anticipate was the Allen wrench needed to reinstall the cross bolt in front of the leaf spring shackle. Fortunately, we had the right size on hand. So far so good. Haven’t had a chance to hook up to my RV yet. I’m optimistic it will take some stress off the leaf springs.

2017 Nissan Titan

I installed this kit on a 2017 Nissan Titan and can be installed very easy. The handling on my truck has improved tremendously. I would recommend this product to everyone.



When I installed it I set it up for 25 load and I pull a 9000 lb dry weight 5th wheel. The suspension kit is still doing its job.


I order these on Friday afternoon and I received them Monday afternoon. I had watched the clip on installation before ordering and it looked pretty easy. The installation instructions are very self explanatory and they were easy to install. From the time I starter until I had the tools picked up and put away it was about an hour and that was with taking a few phone calls. My initial ride after installing these was very good. I drove over a fairly rough road and tracks. My real test will come when I hook up to my trailer and load my tractor or car. I may have to readjust to a heavier setting but it is there if needed.

2008 Nissan Titan

I am on a Nissan titan 08. The roadmaster active suspension is really easy to install here for someone who has very little knowledge when it comes to stuff like this. I was able to do it on my own. I’ll write another review in a couple of months see how it works out here in the Coachella Valley California here we get to 123° weather sand storms so I’m gonna put it thru trials see how good it is.I own a landscaping company and I haul a lot of rock, and DG, boulders.

2011 Nissan Titan

The bed of the truck measured 37.5" with a tool box weighing 200 lbs. The truck felt weighed down with passengers weighing 600lbs. Total weight 800lbs with a tank full of gas. After the install the truck rides smoother and certainly " like new". The stopping distance and acceleration distance have shortened drastically. I'm planning on loading up the bed and the Roadmaster Active Suspension RAS4611. My wife even drive it and she could feel the difference. "It drives like a muscle car." Buy it. Install time at a reputable mechanic shop was a 30 min. Install. I received them today at 1 pm and got it installed at 3:00 pm and finished the install at 3:30pm. It's an investment worth the price over traditional air bag system. Mechanic installed this on 2011 Nissan Titan SV.

Sergio J.


What can I say. After a year of constantly driving through Texas roads and highways. I have moved twice and loaded the bed of my truck plus U-Haul 6x12 trailer and thy truck has not felt the load of it. The Active Road Suspension Leaf Spring is constantly sort of speak sensing if theres load so it can actively push it upwards. I have even driven up to the crazy roads of Pennsylvania and my pick drives smoother than when I got it from the dealer. Im telling you these things work. As any cautious driver upkeeping his own vehicle, I have periodically checked the bolts and location of the resistance in between the spring and it has not deflected or moved from its original installation. I believe every pick up must have these. It beats constantly putting air on the air bags especially in inclement weather like up here in Pennsylvania with the snow. I couldnt be more satisfied with this purchase. Thank you etrailer for offering this superb product.

Sergio J.


Just like when I bought it.

2007 Chevrolet Silverado New Body

I installed these springs on my 2007 Silverado 2500HD that is used for towing a bumper pull horse trailer. With two or three horses in the trailer plus camping gear in the bed, the truck tended to squat more than I liked. These springs totally fixed that issue. I was concerned that they would cause a harsh ride when unloaded and not towing, but I honestly haven't noticed a difference.

To install the springs, the rear of the truck needs to be raised by the frame high enough for the axle to hang freely from the leaf springs. This would be easily done on a lift. It was a little tricky lifting it high enough in my driveway, but it was doable with a large jack and some tall jack stands placed under the forward leaf spring mounts.

To set the tension, I tightened them to the thinner 1mm shim, plus an extra turn or two. It seems to be fine for my purposes so I intend to leave them there.


I've attached two pictures regarding the items I've recently purchased and installed upon my truck from

Chevrolet Silverado 1500

Installed this on my 2020 GMC 1500 Denali. The one thing I hated about my Denali was how much a small amount of weight made it squat. The Denali is meant for smooth ride not towing! These springs brought the back of my truck up by an inch. Truck doesn't squat when being "exuberant" leavin red lights. Ride quality when empty hasn't changed. These springs are AMAZING but, are not a cure for all your hauling needs! When I'm hauling my 1800lb side x side on my trailer they work great! Hauling my 4500lb tractor... Load stabilizer hitch still recommended!

1997 Dodge Ram Pickup

I bought this based on I think the same product I bought several years ago for a 1997 Dodge Ram 1500. At that time, I bought a kit for for a Ram 2500 and was very impressed. I put a truck camper on the Dodge and I don’t think it settled an inch and when I drove it I hardly knew the camper was back there at all. No sway and no handling problems at all. This time I bought the kit for a Nissan Titan, pulling a 25’ travel trailer (about 7000#). The truck rear still settles and is not in a level attitude in transit without the weight distribution hitch. The suspension kit makes it better but not as much as I expected.



Working just fine.

2020 Chevrolet Silverado

The install was straight forward, no lift so it took a couple hours, no problems following written directions. Drove my 2020 Silverado 1500/Diesel around and didn't notice any significant change in the unloaded ride. Very happy with the product, we'll see how it performs when I get my RV behind it.



Still a top notch product! Better ride on the freeway while towing, less bounce. Smooths out rough roads when not towing. Love it!

2015 GMC Sierra

This set up really helped my travel on my 2015 SLT Sierra 1500. I pull a 6,000 pound fish house around in the winter and it reduced the sway I had by about 80%. Plus, my truck didn't sag as much. Great product and worth the money, in my opinion.

2008 Acura MDX

ordered on tuesday arrived on friday Free shipping that was fast. Installed on Saturday morning. after I got the truck on the Jackstands took all if 20 minutes to install. haven't towed anything yet going camping this coming weekend will report more, truck rides better unloaded that before, great customer service

Chevrolet Silverado

It was a pretty easy install and has worked great on my’06 Silverado 1500.



Great. I still have the vehicle and the springs and still on it. No problems.


Product was delivered timely as promised and in good condition. Installation was easy and took about an hour. Taking a trip with the RV next week and will see how it does.

2020 Nissan Titan

I don't like how they raised the back of the truck. And I dont think they do a good job on helping the truck sage when attaching my traveler trailer.

Note I will let them on the truck for now but, I will look at other products to replace them.

2011 Chevrolet Silverado

Install was effortless I set to 20% have not put under a load yet. purchased for added stability pulling my flat bed trailer with my tractor. body roll is definitely better thank you.


Great service as always from! Item was easily installed by myself in 45 minutes. The improvement in handling exceeded my expectations and sway has been eliminated. I have recommended it to several others.



This is a great product! It makes a huge difference particularly when towing. I have recommended it to many others.


I have had these for about a year installed at just a bit tighter than 1mm. I was very skeptical of their claim that they improve the unloaded ride quality, but it really was true. The best way I can describe it is that now the front and rear suspension feels about the same when I hit a bump.... right up until you cause enough travel to include the leaf springs. Then it gets stiff really quickly.

This works because when you install the RAS springs, they pull the ends of the leaf pack together almost like the rear suspension is drooping. This creates a bit of suspension travel that is only controlled by the leaf springs on the RAS. The RAS springs are softer than the leaf pack and as long as the bump doesn't exceed that range, the ride is very compliant. I really like it.

Ride improvement asside, I actually got this for towing my camper. I had a lot of up/down oscillations at the tongue when fully loaded on the highway. The RAS kit did help but hasn't eliminated it. At the Tampa RV show I spoke to the guy at the booth and he suggested I tighten the springs some more. I will do that before my next trip. I'm curious if that hurts the improved ride quality I have. I've also been told to add better equalizers or shocks to the trailer.

I occasionally hear some creaking from them when getting in or out of the truck or when loading the bed. It's nothing I'd ding the rating for, but they're not silent. I never hear anything from them while driving. I live on a dirt road and so far, I've not noticed that cause any issues.

Overall, I'm very happy with the product. I always thought the rear suspension was a little jarring unloaded and this smoothed that out while helping my suspension control heavy loads too. It really is the best of both worlds. I'm sure I'll put them on my next truck.

2015 Silverado Z-71
Equalizer 1k/10k WDH
2019 Grand Design Imagine 2600RB


This product is amazing. I tow a 30ft trailer with my 1/2 ton truck and added these to it for greater stability and control. While it did not completely eliminate all bouncing, it greatly increased the handling and makes the suspension much firmer than it was without them. Also when not towing, the performance of these really shines though! No more rolling sensation while cornering and these really enhance the off-road rally performance of my Chevy Silverado Z71. The added benefit over helper springs is that these adjust to your ride based on the load you are carrying... Heavier load=stiffer ride, lighter loads=better overall handling performance.

Do note... If you are planning to use a 1/2 ton to tow heavy loads, addressing the suspension is only one part of the battle. You also need to consider adding a transmission cooler to ensure you don't overheat your engine. All in all, these were the first addition I made to my truck to improve its towing performance and increase my confidence hauling weight. The benefits were immediate and installation is easy enough for just about anyone with a little DIY tenacity.


Tha RAS Suspension Kit made towing way more enjoyable. Glad I purchased it.

Show More Reviews

See what our Experts say about this RAS Vehicle Suspension

Do you have a question about this Vehicle Suspension?

Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Kathleen M
Video by:
Kathleen M
Employee Jonathan Y
Video by:
Jonathan Y
Employee Randy B
Test Fit:
Randy B
Employee Kevin C
Test Fit:
Kevin C
Employee Mary K
Written by:
Mary K
Employee Wilson B
Updated by:
Wilson B
Employee Matthew E
Updated by:
Matthew E
Employee Noah M
Updated by:
Noah M

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.