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  1. Vehicle Suspension
  2. RAS
  3. Leaf Springs and Helper Springs
  4. Towing/Load Leveling
  5. Heavy Duty
  6. Rear Axle Suspension Enhancement
THIS ITEM IS NOT A FIT FOR
2008 Keystone VR1 Travel Trailer
RAS

RoadActive Suspension Custom Leaf Spring Enhancement Kit - Heavy Duty

Part Number: RAS3611-SLHD
In Stock
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$589.00
Vehicle Suspension
Not Confirmed to Fit

2008 Keystone VR1 Travel Trailer

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3,000-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 - Heavy Duty part number RAS3611-SLHD can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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RAS Vehicle Suspension - RAS3611-SLHD

  • Leaf Springs and Helper Springs
  • Towing/Load Leveling
  • RAS
  • Heavy Duty
  • Rear Axle Suspension Enhancement
  • Suspension Only
  • Helper Springs

3,000-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.


Features:

  • Heavy-duty 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


Specs:

  • Weight capacity: 3,000 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.



3611-SLHD RAS Custom HD Active Suspension System for OEM Leaf Springs - Rear Axle

3611SL-HD

Installation Details RAS3611-SLHD Installation instructions

This Product Fits The Following Vehicles




Customer Satisfaction Score:

Ratings & Reviews

4.7

587 reviews
3,000-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.

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Show More Reviews

See what our Experts say about this RAS Vehicle Suspension

  • RoadActive Suspension Enhancement Recommendation for 2016 Ford F-350 for Towing Camper
    For fifth wheel towing it really is going to depend on the weight of your trailer whether you would want the standard duty RoadActive Suspension Kit part # RAS3611-S or the HD version part # RAS3611-SLHD. One big factor to consider is whether or not you have a dually axle. If that's the case the only fit is the HD version I mentioned part # RAS3611-SLHD which most likely would be best fit since fifth wheel trailers can be pretty heavy. If you have a lighter trailer relative to the towing...
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  • Suspension Enhancement Recommendation for 2018 Ford F-250 Towing Fifth Wheel
    The Roadactive Suspension kits (formerly Roadmaster) are the best suspension enhancement solutions. They give you all of the support you are wanting to get rid of the sag but do not make ride quality worse. Actually they make the ride quality better, improve handling, while reducing sag. If you have factory overload springs you'd want the part # RAS3611-SLHD or if you don't have them you'd want the part # RAS3611-SHD.
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  • Will The RoadActive Suspension System Fit A 2023 Ford F-350 DRW
    Hey Tony, Yes, the RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-SLHD is a confirmed fit for a 2023 Ford F-350 DRW. If your model has factory top overload springs you will have to remove them in order to install the RAS system. These have a 3,000lb load-leveling capacity and the best part about them is that they're designed to only activate when weight is added to the suspension so they won't hurt you unloaded ride quality. Are you hauling varying loads or just...
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  • How to Tell if 2019 Ford F-250 Has Overload Spring for Picking Out RoadActive Suspension
    For your 2019 Ford F-250 there are two RoadActive Suspension kits for your truck available. There's the part # RAS3611-SLHD which is intended for versions of the vehicle that do come with overload springs and there's the # RAS3611-S which does not. Go look at the rear springs on your truck, you should see a bundle of metal springs held together with a metal band. If you see a spring on top of this that looks separate and angles up to make contact with a bracket on the frame that means...
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  • Suspension Enhancement Recommendation for 2025 Ford F-350 Dually
    Hey Jim, for your 2025 Ford F-250 crew cab dually we have the Air Lift LoadLifter kit part # AL73DQ that is a confirmed fit and would work great. It was actually designed specifically for the dually models as well. Are you looking for a compressor kit as well? Are you interested in any non-air bag suspension enhancement kits? If so we have the Roadactive kit part # RAS3611-SLHD that is my favorite all-around option. If that's something you'd be interested in let me know and I can give...
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  • Best Suspension Enhancement Recommendation for 2022 Ford F-250
    Hey Dan, the best option for your 2022 Ford F-250 is the Roadactive kit part # RAS3611-SLHD which will give you exactly what you are looking for. It will give you the additional support needed to get rid of the sag and will also do a great job improving the ride quality and handling as well. I would try this first and if for some reason you wanted more lets talk about a rear sway bar.
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  • Best Suspension Enhancement for 2024 Ford F-350 Towing Toy Hauler that Won't Hurt Ride Quality
    Hey Michael, we have just what you are looking for with the Roadactive Suspension kits like the part # RAS3611-SLHD. Unlike basically all other suspension enhancement kits this one does not have any downsides. This will give you the adjustable suspension support you are looking for as well as improves ride comfort and handling loaded and unloaded which is basically unheard while also doesn't require any maintenance like air bags do. Everyone I've talked into getting one of these kits has...
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  • What is Best Suspension Enhancement that Fits 2019 Ford F-250
    Hey Terry, the unfortunate thing about Timbrens is that they are always harsh when the vehicle is unloaded. If you are concerned about ride quality at all I would not recommend going this route but we can definitely help still. Instead I would highly recommend the Roadactive kit part # RAS3611-SLHD that fits your 2019 Ford F-250. This gives you all the support you are wanting but is also only option that improves ride quality and handling loaded and unloaded. Every other option has a hidden...
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  • Spring Rate of RoadActive Suspension Custom Leaf Spring Enhancement Kit
    According to RoadActive Suspension the spring rate for the standard kit # RAS3611-S is 2,400 lbs. For the heavy duty # RAS3611-SHD it is 3,600 lbs. The heavy duty # RAS3611-SLHD is the same but only designed to fit if you have factory top overload springs on your 2016 F-250. I did ask if that was the actual pounds per inch measurement since it seems rather high and they weren't entirely sure. I know this measurement correlates with the weight capacity of each so it is probably best to...
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  • Recommended Suspension Enhancement For A 2023 Ford F-350 XLT Tremor Edition Hauling An In-Bed Camper
    Hey Cory, Air springs are going to be the best at leveling your F-350 back out once the weight is added but they will most likely affect your unloaded ride quality, even when aired down. That being said, a majority of the unloaded ride quality complaints I've seen have all been on light duty vehicles with less stiff suspensions than your 1-ton Ford so you'd likely not notice the difference nearly as much as others. Air springs would definitely be a top contender for what you're trying...
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  • Recommended Suspension Enhancement for a 2019 Ford F-250 4WD
    I have a couple of options to eliminate the sagging in your rear end that will also improve the handling of your 2019 Ford F-250 4WD. It is the RoadActive Suspension System. The reason this is the best for your F-250 is because it is an active system which works to continually reinforce your original leaf spring suspension. Which system you will need is determined by whether or not your F-250 has the factory overload spring. I have attached a picture below that will help you identify whether...
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    Image 1 for
  • Suspension Enhancement Recommendation for 2022 Ford F-350 Towing Trailer
    Between Timbrens like the part # TFRTT350J and the SumoSprings # SSR-127-54 that fit your 2022 Ford F-350 crew cab long bed I would recommend going with the SumoSprings as you get the support you are wanting without causing the ride quality to be overly harsh. Timbrens do give great support but they are notorious for being pretty harsh. For my best recommendation for your truck I would recommend the RoadActive Suspension kit part # RAS3611-SHD if your vehicle does not have factory overload...
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  • Best Suspension Enhancement for 2020 Ford F-350 Towing Fifth Wheel Trailer
    The RAS systems are by far the best suspension enhancement option for a truck like your 2020 Ford F-350 towing a fifth wheel trailer. You get (adjustable) suspension support which greatly reduces sag, you get improved stability and reduced sway, but unlike other options that make the ride quality rougher these actually are known to improve the ride quality. So if your truck has factory overload springs you'd want the part # RAS3611-SLHD and if you don't have them # RAS3611-SHD.
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  • What Suspension Enhancement Do You Recommend for Hauling Heavy Loads on My 2021 Ford F-350?
    If you plan on towing heavy loads often on your 2021 Ford F-350, I recommend leaf spring enhancements like the RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-SLHD (3,000 pound load rating) or # RAS3611-S (2,000 pound load rating). The reason why I recommend the RoadActive enhancements is because these will ultimately prolong the life of your factory springs. Also, you will be able to manually tension the springs for the desired firmness you need. In addition to these...
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  • Does Overload Spring on 2019 Ford F-350 Need to be Removed to Install RoadActive Suspension
    To answer your first question, yes the top overload spring on your 2019 Ford F-350 dually does need to be removed in order for you to install the RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-SLHD, as you can see by the cut out of the instructions I have added. In regards to raising the rear of your truck when it is unloaded, the RAS kit will not raise it at all, no. One of the great things about this enhancement is that it is an "active" system which essentially...
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    Image 1 for
  • Can Air Bags be Installed on a 2011 Ford F-250 with B&W Gooseneck Hitch Installed
    All of the air spring kits for the 2011 Ford F-250 mount to the sides of the truck frame rails. The issue is that the B&W gooseneck hitch brackets also install in the same location but on the outsides of the frame rails. This would not be a problem if the B&W brackets holes in them to match the frame holes located directly above the axle. This is the hole that nearly all of the available air spring kits use for your truck. You would have to drill the holes into the B&W brackets. If you...
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  • What RoadActive Suspension Kit Do I Need For My 2022 Ford F-250 Cab And Chassis
    Yes The RoadActive Suspension kit # RAS3611-SHD will be a good fit for your 2022 Ford F-250 cab and chassis. Provided it does not have factory top overload springs. If it does have factory top overload springs you will want to go with # RAS3611-SLHD instead. These can be identified by looking at the top of your leaf springs and will basically look like another leaf that is not connected to the rest. I have attached a picture that should explain what they look like a bit better.
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    Image 1 for
  • Can RoadActive Suspension Be Used on a 2019 Ford F-350 With Top Overload Springs?
    Due to the design of the RoadActive Suspension # RAS3611-SLHD you would have to remove the upper overload spring on your 2019 Ford F-350 to use their system. As an alternative if you wish to keep the top overload spring this will depend on if you have the 3" block between the leaf spring and the top overload spring. If you do have this block you will want to look at the SuperSprings SuperSway Stops # SS65GR. Otherwise the SumoSprings Rebel Custom Helper Springs # SSR-128-40-2 would be a...
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  • Does Installing RAS Leaf Spring Enhancement RAS3611-SLHD On 2020 Ford F-350 Affect Ride Quality?
    The RoadActive Suspension Custom Leaf Spring Enhancement Kit - Heavy Duty # RAS3611-SLHD you were looking at is designed for trucks with the upper overload spring and will include everything needed to remove it on your 2020 Ford F-350. The # RAS3611-SLHD will basically act as a better overload spring meaning it will not ruin your unloaded ride, and will actually improve traction, reduce sway and body roll, and eliminate axle wrap so you will have a much more enjoyable loaded and unloaded...
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  • Recommended Anti-Sway Bars And Suspension Enhancement For A 2022 Ford F-350
    Hey John, Since body lifts only move the body away from the frame and don't change the distance between the frame and suspension the lift should be irrelevant to fitment in your case. For anti-sway bars I recommend the Roadmaster Front Anti-Sway Bar # RM-1139-180 and Rear # RM93VR. For the # RM93VR to fit you'll need the forward leaf spring bump pads, on either side, to be bolted to the frame and not riveted. For DRW models you'll want the # RM-1139-193 instead of the # RM93VR. As for...
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  • Can RoadActive Suspension and Anti-Sway Bar Both be Used on 2017 Ford F-250
    You can certainly add both of these to your 2017 Ford F-250. The RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-SLHD and Roadmaster Rear Anti-Sway Bar # RM-1139-173 would work well together. The Sway bar is going to help minimize side-to-side movement and helps balance weight transfer. It is especially helpful for top heavy loads and keeping your vehicle in line. The RAS kit will support and strengthen your leaf springs for an improved ride quality. These will also...
    view full answer...
  • What Suspension do You Recommend for My 2022 Ford F-350 Super Duty when Towing a Fifth-Wheel?
    For a great suspension enhancement for hauling your fifth-wheel trailer on your 2022 Ford F-350 Super Duty, I recommend the RoadActive Enhancement Kit # RAS3611-SLHD. This kit will fit 2-wheel and 4-wheel drive models as well as single rear-wheel and dually models. Apart from the kit's 3,000 pound capacity, the leaf spring enhancements greatly extend the life of your factory springs. This is super important to consider if you plan to haul your fifth-wheel trailer often. Also, the leaf spring...
    view full answer...
  • Recommended Suspension Enhancement For Occasional Towing For 2021 Ford F-350 SRW
    Suspension enhancement is a very good idea for your 2021 Ford F-350, even with just occasional towing, but especially for longer trips as your truck will be easier to handle with a more level ride. What I highly recommend for your F-350 is the RoadActive Suspension, with the correct option depending on if you have top overload springs or not: - WITH Top Overload Springs: RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-SLHD - WITHOUT Top Overload Springs: RoadActive...
    view full answer...
  • RoadActive Suspension Kit that Fits 2020 Ford F-250 with Overload Springs
    For versions of the 2020 Ford F-250 Super Duty with the factory overload springs we have the RoadActive Suspension kit part # RAS3611-SLHD as a confirmed fit. This fits your Tremor model.
    view full answer...


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