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  1. Vehicle Suspension
  2. RAS
  3. Leaf Springs and Helper Springs
  4. Towing/Load Leveling
  5. Rear Axle Suspension Enhancement
  6. Standard Duty
RoadActive Suspension Custom Leaf Spring Enhancement Kit
etrailer Installation
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RAS

RoadActive Suspension Custom Leaf Spring Enhancement Kit

Part Number: RAS27ZR
In Stock
$539.00
Vehicle Suspension

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etrailer Installation
We'll connect you with nearby partnered installers who know this exact setup.
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 RAS27ZR can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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  • Reviews (544)
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RAS Vehicle Suspension - RAS27ZR

Highlights

  • Custom Fit for Your Vehicle: Mounts to existing attachment points
  • 2,000-lb Load Support: Keeps your ride level when towing or hauling heavy loads for safer control.
  • More Stability and Grip: Reduces sway, body roll, and wheel hop so handling feels steady and predictable.
  • Protects Suspension Parts: Lessens strain on leaf springs, shocks, and tires to extend their life.
  • No Upkeep Needed: Once bolted on, it works automatically without adjustments or maintenance.
  • Rust-Resistant Build: Epoxy e-coated steel and corrosion-resistant brackets hold up against harsh elements.
Made in USA

Features to know about

Stay Level Under Load: 2,000-lb Active Suspension Support

When you hitch up a trailer or drop a heavy load in the bed, the last thing you want is rear-end squat or unsteady handling. The RoadActive Suspension Custom Leaf Spring Enhancement Kit adds up to 2,000 lbs of support by turning your passive leaf springs into a mechanically active system. Its variable-rated coil tension springs automatically adjust as weight increases, keeping your ride level and stable without relying on air pressure or manual adjustments.

Vehicle equipped with RoadActive Suspension showing level ride height under load to demonstrate improved balance and traction.

Drive With Confidence: Improved Stability, Handling, and Control

Sway, bounce, and body roll can make towing and hauling stressful. This system strengthens your factory leaf springs so they respond instantly to load changes, reducing sway and keeping the truck planted through turns and highway speeds. The active design helps eliminate bottoming out, axle wrap, and wheel hop—so braking, acceleration, and steering all feel more controlled under load or on rough roads.

RoadActive Suspension system installed on a rear axle demonstrating how it prevents axle wrap and wheel hop for improved vehicle stability.

Smooth Ride When Unloaded: Automatically Disengages for Comfort

Unlike systems that stiffen the ride when empty, the RAS kit disengages its coil tension springs when the vehicle is unloaded. That means your factory suspension keeps its normal movement and comfort without the harshness of a constant helper spring. You get support only when you need it and a smooth, compliant ride when you don’t.

Customized Setup for Real-World Loads: Independent Side-to-Side Adjustment

Every load is different—sometimes weight sits off-center or shifts with use. During installation, each coil spring can be set between 25- and 40-percent tension using included spacers. You can fine-tune side-to-side balance for uneven loads like toolboxes or campers while keeping handling consistent across both wheels.

Close-up of RoadActive Suspension adjustable coil tension spring with spacer used to set proper spring tension during installation.

Built to Last: Durable Steel Construction With Corrosion Resistance

Heavy work demands strong parts. Each RAS unit is made of high-grade alloy steel with an epoxy e-coated finish for long-term corrosion protection. The brackets have more than 800 hours of salt spray resistance, so they hold up through wet roads and winter grime. Once bolted on—no drilling or welding required—the maintenance-free setup stays ready for every trip without constant checks or adjustments.

Close-up of RoadActive Suspension unit highlighting epoxy-coated steel construction for corrosion resistance and durability.

Fully installed RoadActive Suspension unit mounted on vehicle leaf springs showing bolt-on installation with factory U-bolts.

Close-up view of RoadActive Suspension variable-rated coil tension spring showing its construction and mounting position.

Specs

Weight and Capacity

  • Weight capacity: 2,000 lbs
  • RoadActive Suspension will not increase your vehicle's weight-carrying capacity

Diagram showing labeled components of the RoadActive Suspension kit installed on a leaf spring assembly for visual reference of system configuration.

Warranty

  • 5-Year warranty
  • 30-Day money-back guarantee

3621-T RAS Custom Active Suspension System for OEM Leaf Springs - Rear Axle



This Product Fits The Following Vehicles




Ratings & Reviews

4.7

544 reviews
Review sort icon
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.

by:

I installed the Road Active suspension standard duty kit on my 2017 Tundra. I was hoping for a smoother ride with and without a load and I was not disappointed. I don’t do heavy hauling, just a center console boat that weighs about 3000 pounds with trailer. My truck definitely has a smoother ride. It is especially noticeable on rough spots like bridge crossings, etc. I set the springs somewhere in between the light and heavy settings. I used a quarter as a spacer. It raised the rear of my truck one inch. I definitely recommend the Road Active suspension and etrailer is the best place to buy it.



by:

Helps immensely, 12x6 inclosed trailer from NY to Florida and back up to NJ no problems



by:

Made all the difference in the world! Also, easy to install. Yes, the ride is stiffer, but when I'm dragging the 10K of weight in the trailer, it's worth it.



by:

Easy install when I rotated tires. Forgot to measure height difference, but it did raise a bit. I like the adjustability and not having to remove springs and shackles to add a leaf. Will be towing the camper with improved support.



by:

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.



by:

I Have had this suspension on multiple trucks and i love it . It takes the sway out of the truck when entering a exit ramp and taking sharp turns with a trailer or without, also reduces wheel hop and increases payload in the bed of the truck.I would recommend for all trucks pulling trailers.



by:

Hands down the engineering behind the product was well executed and would recommend it to anyone who's travels involve pulling any type of trailer. You will feel a much smoother ride even when not pulling a trailer at all.



by:

I received this kit in a very timely manner always do from etrailer have some issues with the instructions that come from roadmaster not a trailer the bump stop spacer didn’t say that you need to use the original bolt from the bump stop so it slowed me down greatly on the install however I took it out on a quick run without a load I do feel that this has made the unloaded ride smoother tomorrow I’ll be taking the trailer out for a bit and we’ll see how it works there and I’ll update this rating.



by:

I found this items cheaper on another site but etrailer match and then beat the price.
Item installed super easy, more work jacking up the truck and taking the tires off. Can be installed with out removing tires just make it easier to get it in. The item did lift the back of my truck 1 inch. See Pics.



by:

Easy install 2011 Tacoma crewcab long bed. Helped with sag when towing microlite travel trailer. Keeps the rear end raised in the rear a little when unloaded, but I like that look. Only complaint and its nothing big when truck is unhooked and empty when i get out I can hear alittle noise from RAS. Sort of like a bedspring coil. Night pic is with RAS installed daylight pic is with out installed



by:

I’ve bought a lot of products from etrailer and as always everyone I dealt with is professional and knowledgeable of the numerous products they sale. I used every resource they offer to help me decide what type of suspension upgrade I was going to use to improve the haul and tow ability of my 2017 diesel chevy Colorado 4x4 crew cab short bed. I chose the RAS system from Roadmaster. I also called them and ask some very detailed questions about using my OEM shackle instead of replacing with the plates in the kit and was told that was fine and that others had also. I got professional and knowledgeable info that helped make my decision. The product is exactly as promoted and every review out there on the internet about how good or unchanged the unloaded ride is after installing are true. My truck rides better now and it was already quieter and almost as smooth as my wife’s Cadillac. If your looking to improve the drive, tow and haul ability of your leaf spring vehicle, and I say vehicle instead of truck because I don’t know if they have them for other leaf spring vehicles, you are not going to find a better easier to install product that does that for your loaded or unloaded vehicle, IMHO. I will update in a year after next spring mulch haul. I don’t expect zero squat but hope to reduce and improve loaded steering performance. Took longer to jack up truck and remove tires than install kit.



by:

I love the product since i have a 2021 toyota tacoma crew cab long bed with a campertop a robber mat and a jack thats around 450 pounds that a have at all times my truck was sittind low a lilbit plus it was swagging on the road i have summo spring to help my suspention but it was not enoght so i did my research but this was my better option i just installed it yerterday july-8-2021 and went for a ride where i ussually drive everyday and WOW now my truck rides very smood plus it lift my tryck 1 inch on the back now my tryck seats level it took me about 2 hrs but i did right i just follow the intructions and done i love the product the only thing that im concern is that the left side underneat the springleaft there is a breik line that is too close to the roadmaster suspention i hope that with the time dont hit that line because if it does thats the line for the breiks and i will be in trouble replacing it other wise evreything works great i recomend it 100% thanks guys i will buy it again?????best $500 that i spend on my truck



by:

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.



by:

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.



by:

Balances ability to tow my 1800 squaredrop Hiker camper with 350 tongue weight as well as roof top tent on Leer 180 camper topper. Better handles load and side to side tipping on '21 Ranger. Keeps sage to a minimum.



by:

I have put these on every pickup that I have owned and not only does it assist with heavy loads, my tires have gone past 80,000 miles before needing replacement. All Chevy Duramax 2500's and 3500's!!



by:

Did not fit my 1995 F-150. ETrailer was very helpful in an effort to make any adjustments needed. We all decided that they were a "no go" for installation. Return was made easy. I have bought several other pieces of gear since. Thank Etrailer.



by:

i installed these on my 2001 ford f-250 4x4 and this is a huge upgrade whether your towing or empty.truck rides and handles better than it ever has. easy straight forward installation. you will need a t-55 for the front bolt and a 12mm ratchet wrench for the adjustable bolt that tightens the spring and a couple of 22mm and a 19mm wrench or crescent wrenches for the jam nuts. i took the weight off of the leaf springs for easy adjustment of the coil spring and used the thinner of the two disc that came with the kit and it raised the rear of the truck up exactly 1 inch empty without a trailer connected. if you use the thicker disc it will raise it more.



by:

I haven't hooked up my camper yet but set the springs up with the white wafer and it raised my truck 1 1/2 inches which is the amount it dropped after I put on a fiberglass topper. The ride is just a bit stiffer but a lot less body roll I noticed. Not impressed with the 25 Silverado suspension compared to my previous 2017 truck. If the squat is still there after I hook up the camper, there is plenty of adjustment left.



by:

These made such a difference in the ride of my pick up while pulling my enclosed trailer. Let’s squat more stability.



by:

Great product, helps with sway and when the truck has additional weight it progressively compensates. I would add this to any vehicle with leaf springs.



by:

I don’t think they are really made for the old PU. 1997 k1500 8 ft bed with a 750 lbs camper tong weight I think I had to put to much pressure on the Kurt stabilizer chains to get level. It looked like the newer truck reviews on YouTube were great thanks Dingler.



by:

2023 F150. Install was fairly easy. Set at 25%. Ride unloaded a bit stiffer, but handling much better. Lifted rear of truck about an inch. Towing 7500 lb camper down NYS thruway which is crowded with much unforgiving bumps and pot holes the ride was more manageable. The 25+ mph cross winds did make for quite a bit of sway still, not as bad as before adding the RAS. Still felt passing trucks trying to suck me in, not as bad as before.
I plan on cranking the RAS to 40% on next camping trip and hopefully give the RAS 5 stars.



by:

I purchased the RAS system 6 months ago to help with rear end sag & control while towing our 22 ft 4200lb camping trailer. It improved sag & helped handling even when not towing! I don't get the bounce when driving on bumpy uneven roads the wheels stay planted on the road. I recently purchased a 8000lb camping trailer & my 24 1500 Silverado handles it very well, I will adjust the RAS to the next step up for the extra weight when time permits.
The install took just over an hour with help from a friend & a car lift which is good since I'm 70 years old.
Great product!



by:

Just perfect to level the rear of my GMC 1500 Denali with the 29' Airstream (900 lb tongue wt). Preload is set at 1mm. I tried 2mm and it was overkill for this application. I was pleased with how easy the install was. I had to use a two jack hack to get the rear tires off since my 19" lift floor jack didn't quite have enough reach. You lower the differential after the tires are off so the rear axle is hanging free for the install. See photos


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See what our Experts say about this RAS Vehicle Suspension


Info for this part was:

Employee Daron K
Edited by:
Daron K
Employee Alex H
Written by:
Alex H

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