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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: RAS4529-XT
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 RAS4529-XT 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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  • Videos (1)
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RAS Vehicle Suspension - RAS4529-XT

Highlights

  • Custom Fit for Your Vehicle: Mounts to existing attachment points
  • 2,000-lb Load Stability: Keeps your ride level under heavy tongue or bed weight for safer towing.
  • No Maintenance Needed: Once installed, it automatically adjusts to load without monitoring or upkeep.
  • Smoother, Controlled Ride: Reduces sway, bounce, and body roll so handling feels steady and predictable.
  • Protects Suspension Parts: Prevents axle wrap and wheel hop to extend leaf spring and shock life.
  • Simple Bolt-On Install: Fully assembled kit mounts under leaf springs with no drilling or cutting required.
Made in USA

Features to know about

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

Heavy trailers, campers, or bed loads can make the rear end sag and throw off your steering and braking. This RoadActive Suspension kit gives your leaf springs up to 2,000 lbs of support by turning them into a mechanically active suspension system. The variable-rated coil springs automatically adjust to your load, keeping your ride level and steady whether you’re towing or hauling. You get better traction, balanced weight on all tires, and smoother control when braking or accelerating.

RoadActive Suspension system installed on a vehicle’s rear axle demonstrating level ride height and improved traction under heavy load conditions.

Cut Down on Sway, Bounce, and Body Roll: Active Coil Tension Springs

When corners or crosswinds push your truck around, the RAS system steps in before sway or body roll even start. The built-in coil tension springs instantly absorb and dissipate load forces so the back end stays planted through turns and over rough roads. That means less rocking when a semi passes by and more confidence when driving curves or uneven highways with a heavy load behind you.

Stop Bottoming Out and Wheel Hop: Mechanically Active Design

Axle wrap and wheel hop aren’t just annoying—they wear out suspension parts fast. Each RAS unit stabilizes the leaf springs to absorb force under load so they don’t twist or flatten out. By keeping the springs in their natural bowed shape, this setup eliminates axle wrap, prevents wheel hop, and stops bottoming out on rough pavement or steep inclines. Your shocks, shackles, and tires last longer because the system spreads stress evenly across the suspension.

Close-up of RoadActive Suspension installed on a vehicle’s rear axle showing stabilization that eliminates axle wrap and wheel hop under load.

Set It Once and Forget It: Fully Assembled, Maintenance-Free Kit

This kit comes fully assembled for easy bolt-on installation—no drilling, cutting, or welding needed. Once adjusted during setup, it works automatically without valves, compressors, or air lines to monitor. The corrosion-resistant epoxy e-coated steel construction holds up with a salt spray rating of more than 800 hours, so you can count on durable performance season after season without extra maintenance or tuning before each trip.

Specs

Weight and Capacity

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

Warranty

  • Warranty: 5-Year warranty
  • Guarantee: 30-Day money-back guarantee

4529-XT RAS Custom Active Suspension System for OEM Leaf Springs - Rear Axle

Installation Details RAS4529-XT Installation instructions

This Product Fits The Following Vehicles




Video of RoadActive Suspension Custom Leaf Spring Enhancement Kit
Video Thumbnail Video Player Dialog

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Review of RAS Vehicle Suspension - Rear Axle Suspension Enhancement - RAS4529-XT

Hello, everybody, Steve here with etrailer.com. Today we're looking at our RoadActive Suspension. It's a custom leaf spring enhancement kit. Now folks, these are a custom fit application, so make sure you're checking out our fit guide here at etrailer.com's home page. Enter things like year, make, and model. Make sure you're getting the right parts the first time.

Now folks, whether you're towing a heavy trailer or carrying a load in your truck bed, sagging can be both dangerous and frustrating. But with the RoadActive Suspension kit, this is gonna transform your vehicle's rear leaf springs into what's considered a mechanically-driven active system. So no airbags to mess with, no leaks, anything like that to ever have to worry about. These will keep your ride level with a 2,000-pound capacity. And they're gonna instantly support the extra weight, thus preventing sag and maintaining your vehicle's stability whether you're towing a camper or just filling up the back of the truck with gear.

Now, these are going to instantly respond, and they're going to immediately react with the weight without affecting your ride quality. Now, zooming in, you can see the heavy-duty spring construction and all the parts have been powder coated. So you don't have to worry about rust, corrosion, those kinda things. And per the instructions, you'll mount these in unison with your factory suspension system. And they will tell you how and where each piece mounts up to be safe and effective.

Now, they basically mount to your existing attachment points on the vehicle on the rear leaf spring suspension to help stable out the hauling, towing, whatnot. Well, folks, that's gonna wrap it up for our quick look together. Again, my name is Steven. Thanks so much for your time. Thanks for watching.

As always, we do welcome feedback and photos of these installed. Let us know how they perform before and after you've installed these. Have a good one.

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:

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:

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 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:

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:

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:

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:

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



by:



by:

The RAS achieved what I was looking for. Better overall ride and no more bottoming out the leaf springs with a load. I did have to cut some threads off the end of one of the shock mounting bolts for it to be properly installed on my 2012 Xterra but other than that, install was easy as advertised. I’d def recommend. This raised the back of the vehicle about 1”. The only question remains is how well they’ll hold up to winter salt over the years.


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See what our Experts say about this RAS Vehicle Suspension

  • Suspension Enhancement Recommendation for 2011 Nissan Xterra Pro-4x
    Hey Don, if you were wanting to go with something that will give you the suspension support you are looking for without destroying your ride quality you would want the Roadactive kit part # RAS4529-XT which gives you all of the support you are looking or without any of the downsides commonly associated with these types of kits. The ride quality loaded and unloaded will actually be improved with this while also offering adjustable support so you can really dial it in. Have you tried air...
    view full answer...
  • Recommended Leaf Spring Suspension System for a 2012 Nissan Xterra
    No, you can not and the Hellwig EZ-550 Helper Springs item # HE72FR mount on top of the leaf springs. However, they do not fit a 2012 Nissan Xtrerra. The only option we have for a leaf spring system for your Nissan are the RoadActive Suspension Custom Leaf Spring Enhancement Kit item # RAS4529-XT for 4WD or item # RAS4529-XT for 2WD.
    view full answer...
  • Timbren or RoadActive Suspension Kit Recommendation for 2012 Nissan Xterra
    Overall the RoadActive Suspension kit part # RAS4529-XT will be better. It will give you the additional support you want, it will help make the vehicle handle better, but what really makes it stand out is that it won't make the ride quality as harsh as the Timbren # TJRC01 would.
    view full answer...
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  • Does RoadActive Suspension For 2008 Nissan Xterra Need to be Adjusted When Not Towing
    Nope, you will not need to adjust the tension either before or after towing of the RoadActive kit that fits your 2008 Nissan Xterra, which is the following part number: - RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS4529-XT The # RAS4529-XT is designed not to affect the unloaded ride of your Xterra, and can even improve it because the kit is designed to work with your current suspension. It is an active system, meaning it works when needed; so if you go over a pot hole...
    view full answer...
  • Suspension Enhancement Recommendation for Lifted 2010 Nissan Xterra
    For suspension enhancement for your 2010 Nissan Xterra that is lifted we have options but with the air bag setups there isn't a way to install them due to the way they install like you noticed. Instead the best option is the RoadActive Suspension kit part # RAS4529-XT which gives you adjustable suspension support that will work well with the lift kit. Unlike other options this helps the loaded and unloaded ride quality as well as improves handling.
    view full answer...


Info for this part was:

Employee Jameson C
Expert Research:
Jameson C
Employee Steven C
Installed by:
Steven C
Employee Mary K
Written by:
Mary K
Employee Wilson B
Updated by:
Wilson B
Employee Michael B
Updated by:
Michael B
Employee Noah M
Updated by:
Noah M

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