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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
THIS ITEM IS NOT A FIT FOR
2007 Dodge Sprinter
etrailer Installation
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RAS

RoadActive Suspension Custom Leaf Spring Enhancement Kit

Part Number: RAS3612
In Stock
$539.00
Vehicle Suspension
Not Confirmed to Fit

2007 Dodge Sprinter

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etrailer Installation
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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 RAS3612 can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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  • Reviews (542)
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RAS Vehicle Suspension - RAS3612

Highlights

  • Custom Fit for Your Vehicle: Mounts to existing attachment points
  • 2,000-lb Load Support: Keeps your ride level and stable when towing or hauling heavy loads.
  • Better Handling and Control: Reduces sway, body roll, and bounce for safer highway driving.
  • No Upkeep Needed: Once installed, it works automatically with no adjustments or maintenance.
  • Protects Suspension Parts: Less stress on leaf springs, shocks, and tires extends component life.
  • Quick Bolt-On Install: Fully assembled kit mounts under leaf springs with no drilling or welding.
Made in USA

Features to know about

Stay Level and Confident Under Load: 2,000-lb Rear Suspension Support

When hauling a heavy trailer or bed load, sag and squat can throw off your steering, braking, and headlight aim. The RoadActive Suspension Custom Leaf Spring Enhancement Kit adds 2,000 lbs of support to your rear suspension, strengthening your leaf springs so your vehicle stays level and stable. The system activates right when weight is added and automatically adjusts coil tension to match the load. Even under full weight, you keep the balanced stance and steady control that stock springs can’t hold on their own.

Comparison image of vehicle ride height showing how RoadActive Suspension keeps vehicle level under heavy load.

Smooth Ride Whether Loaded or Empty: Mechanically Active Variable-Rate Springs

Unlike setups that stiffen your ride when unloaded, this mechanically active design only engages when it’s needed. The variable-rated coil tension springs react the moment a load is applied, adding resistance as weight increases. When unloaded, the coils disengage so your factory springs move naturally without harshness or bounce. You get stability when towing or hauling and a comfortable ride when running light—no switches, air pressure adjustments, or maintenance required once installed.

Close-up view of RoadActive Suspension variable-rate coil tension spring that adjusts to vehicle load for improved ride stability.

Tame the Bounce and Body Roll: Built-In Sway and Wheel Hop Control

Heavy loads can twist leaf springs and cause sway or wheel hop that makes towing feel sketchy. The RAS kit locks this down by reinforcing the spring pack to stop axle wrap before it starts. It cuts out wheel hop for better traction while accelerating or braking, and it reduces sway and body roll through turns or crosswinds. The result is a steadier, more predictable ride that feels planted even with a trailer behind you or gear stacked in the bed.

Illustration showing how RoadActive Suspension eliminates axle wrap and wheel hop by stabilizing vehicle leaf springs under load.

Quick DIY Upgrade That Lasts: Fully Assembled, Bolt-On Design

This kit comes fully assembled and bolts right onto your existing leaf springs—no drilling, cutting, or welding required. Each unit secures under the spring pack using the factory U-bolts for a solid fit that’s easy to tackle with hand tools. Once installed, there’s nothing more to adjust or maintain. The epoxy e-coated steel construction resists corrosion with brackets rated for more than 800 hours of salt spray, so it’s ready for long-term use in real-world conditions without constant upkeep.

RoadActive Suspension kit fully installed beneath vehicle rear leaf springs showing bracket placement and fitment.

Close-up detail of RoadActive Suspension steel construction with epoxy e-coated coils and corrosion-resistant brackets.

Specs

Weight and Capacity

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

Warranty

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

Diagram of RoadActive Suspension kit installed on vehicle leaf spring system showing how components attach and function together.

3612 RAS Custom Active Suspension System for OEM Leaf Springs - Rear Axle

Installation Details RAS3612 Installation instructions

This Product Fits The Following Vehicles




Ratings & Reviews

4.7

542 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 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:

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:

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



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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



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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.



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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.



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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:

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:

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



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:

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’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 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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Had for a year and still working great.



by:

Put on my F150. Did the job. Great product. Easy install.

Donald profile picture

Donald

3/16/2022

This product is awesome. Does what it is suppose.



by:

Install was easy, about one hour and that's mostly because it was cold out.

Michael profile picture

Michael

3/14/2022

One year later and Im just as pleased now.



by:

It has made a great difference in towing my motorcycle trailer.. lifts like I need for towing, by accepting the extra weight ! It’s easy to make adjustments as needed !!



by:

I bought these after seeing them on television. My truck dropped in the back when towing a horse trailer. Ruined my front tires. These kept the truck level with the horse trailer attached and even improved the ride when there was no load. Raised the rear about two inches I think. I highly recommend them.

Tim J. profile picture

Tim J.

6/4/2021

Still very happy.


25
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See what our Experts say about this RAS Vehicle Suspension

  • Rear Suspension Enhancement for 2008 Ford F-150 to Reduce Suspension Sag When Towing
    The amount of tongue weight you have at 965 lbs it probably higher than what your F-150 is rated to tow which is why you are experiencing sag even with a weight distribution system. Suspension enhancement can help give you more support but if you are above the weight capacity of your vehicle suspension enhancement would not be enough to allow you to safely tow beyond that. The SumoSprings kit part # SSR-108-40 would give you an additional 1,000 lbs of support when towing though and would...
    view full answer...
  • RoadActive Suspension Kit For 2005 Ford Econoline E150 Van
    Hello Angel. We do have an RAS system that will fit your 2005 Ford Econoline E150 Van, but the # RAS3611 you mentioned is only recommended for the E350 models, so this will not work for you. The correct RAS kit for the 2005 E150 is the following: - RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3612
    view full answer...
  • Determining Correct Bolt Hole To Install RAS Leaf Spring Enhancement RAS3612 On 2008 Ford F-150 2WD
    I would be happy to go over how to determine which hole of the RoadActive Suspension Leaf Spring Enhancement Kit # RAS3612 will be correct for your 2008 Ford F-150 2WD. You are correct that this kit has 5 holes on the end of the # RAS3612 that goes underneath the leaf springs. The reason for this is it allows the same kit to fit multiple years and models of vehicles. When installing the kit you will place the opposite end over the eye of the leaf springs on your F-150, and then use the...
    view full answer...
    Image 1 for
  • Will the RoadActive Suspension # RAS3612 Fit with Timbrens Installed on a 2001 Ford E-150 2WD
    If you are wanting to add some additional support to the Timbren System, like part # TFER15087, for your 2001 Ford E-150 2WD then the RoadActive Suspension # RAS3612 is a great option. It won't get in the way of your Timbren system and it doesn't require maintenance like an air bag system would. Should you end up wanting some front suspension enhancement then I recommend the SuperSprings SumoSprings. These have the same concept as the Timbrens but we have heard from customers that they...
    view full answer...
  • Best Suspension Support for 2008 Ford F-150
    The RAS systems are the best options for suspension support. They give you adjustable suspension support that's easier to install, less maintenance, and unlike other options actually improves ride quality instead of diminishing it. So for your 2008 Ford F-150 you'd want the part # RAS3612 and you'd be set.
    view full answer...
    Image 1 for
  • Rear Suspension Enhancement Compatible With Lifted 2004 Ford F-150
    You will be able to still use some suspension upgrades on a lifted 2004 Ford F-150. If the lift kit you have does not change the rear leaf springs on your F-150 you can still use one of the following kits. TorkLift StableLoad Suspension Upgrade w Quick-Disconnect # TLA7311S RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3612 SuperSprings Custom Suspension Stabilizer and Sway Control Kit # SSA28 The Timbren Rear Suspension Kit # TFR1502D can also be used provided you...
    view full answer...

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Info for this part was:

Employee Mary K
Written by:
Mary K
Employee Wilson B
Updated by:
Wilson B
Employee Noah M
Updated by:
Noah M

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