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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
FITS 2008 GMC Sierra
RoadActive Suspension Custom Leaf Spring Enhancement Kit - Heavy Duty
RAS

RoadActive Suspension Custom Leaf Spring Enhancement Kit - Heavy Duty

Part Number: RAS3611-HD
In Stock
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$589.00
Vehicle Suspension
Confirmed to Fit
2008 GMC Sierra

2500

3500 - Pickup

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2008 GMC Sierra vehicle suspension from RAS. Product reviews from other Sierra owners. Expert vehicle suspension advice with thousands of helpful questions and answers. Great prices and fastest shipping.
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2008 GMC Sierra - RoadActive Suspension Custom Leaf Spring Enhancement Kit - Heavy Duty

  • 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 GMC Sierra'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-HD RAS Custom HD Active Suspension System for OEM Leaf Springs - Rear Axle



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

  • Suspension Enhancement for 2020 GMC Sierra 2500
    If you're towing most of the time then I would go with the Timbren Rear Suspension Enhancement System # TGMRCK25D. These will provide the most support for your 2020 GMC Sierra 2500 while towing your 5th wheel. If you're more concerned about ride quality then the RoadActive Suspension # RAS3611-HD would be the better choice. The Timbren has a tendency to be a bit rough when you aren't towing or hauling. If you want the best option possible I would go with the Firestone Air Bags # F2709....
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  • Rear Suspension Helper Springs for a 2018 GMC Sierra 2500 Towing a 5th Wheel Trailer
    Hello, I will be happy to help you select some helper springs to improve the ride and level out the truck when you are towing. Timbren springs are an easy install but they will make the ride stiffer when you are not towing. The similar SumoSprings Solo # SSR-207-47 will also level out the truck but will not be as stiff when not towing compared to the Timbren springs. Another option to consider is RoadActive Suspension # RAS3611-HD. Installation is easy with this kit as well. It will...
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    Image 1 for
  • Will RoadActive Suspension Kit Reduce Sag in 2017 GMC Sierra 2500?
    Though there is not a specific number I can offer, what I can tell you is that the Roadmaster Active Suspension Kit # RAS3611-HD is designed to level your 2017 GMC Sierra 2500 under a maximum 3,000 lb load. So what will happen is you will no longer experience the 1" of sag you said you were encountering, though your trailer will ride an inch higher in front. This is going to be true regardless of the suspension enhancement though there may be a solution. If you haven't already, unbolt...
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  • Suspension Enhancement Kit Recommendation for 2016 GMC Sierra 3500 Towing Fifth Wheel Trailer
    The Roadmaster Active Suspension Kit part # RAS3611 would be a great suspension enhancement setup for your 2016 GMC Sierra 3500. You would not need air bags on top of these. Since these will give you the additional support you need the air bags would be redundant.
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  • Would Install of Roadmaster Active Suspension Kit Cause Driveshaft Angle to Change
    The pinion angle would slightly change if you installed a RoadActive Suspension kit part # RAS3611-HD and you were using enough suspension support to change the ride height but it would not be enough of a change to require to change anything. You would not need to make any changes to compensate for this.
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  • Will Roadactive Suspension Kit for 2005 Ford F-250 Reduce Sag
    Hey Nathan, yes the Roadactive system part # RAS3611-HD will do a great job helping with this. This is my favorite suspension enhancement kit to recommend because it gets rid of the sag and unlike other options improves loaded and unloaded ride quality as well as improved handling. You'll love it.
    view full answer...
  • Suspension Enhancement and Gooseneck Hitch Recommendation for 2016 Nissan Titan XD
    Hey Andrew, we can help with suspension enhancement that fits your 2016 Nissan Titan XD and will work great with a fifth wheel hitch but none of the air bag kits we offer fit with fifth wheel rails as they install on the truck frame in the same location. So instead I would go with the Roadactive kit part # RAS3611-HD as this will give you the support you are looking for, is easily adjustable, less maintenance that air bags, and unlike all other options improves ride quality and stability...
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  • Suspension Enhancement Recommendation for 1997 Ford F-250 with B and W Gooseneck Installed
    I have a really great suspension enhancement kit that fits your 1997 Ford F-250 with a Turnoverball gooseneck installed but none of the air bag kits fit with your hitch. Instead I would recommend the RoadActive Suspension kit part # RAS3611-HD which does fit and gives better support. It's very easy to install, easy to adjust, and unlike other options actually improves handling and stability. This also means you don't ever have to mess with adjusting air pressure or worry about air leaks.
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  • Recommended Suspension Enhancement For A 2007 GMC Sierra 2500 With An In-Bed Camper
    Hi Mary, Do you leave the camper in the bed most of the time or does this truck spend a good chunk of time driving around without the camper? The SumoSprings Solo Custom Helper Springs # SSR-211-54 would be a great option if you leave the camper in the bed all the time. They take about 20 minutes to install and would just essentially replace the factory jounce stops for hassle-free, no-maintenance load leveling support. These have a 2,800lb capacity so they're be a bit stiff when the...
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  • Recommended Suspension Upgrade to Handle Axle Wrap on a 1998 Ford F-250 LD
    No, they will not but I have something that does. The SuperSprings Custom Suspension Stabilizer and Sway Control Kit item # SSA13 does a great job of keeping your F-250's rear end from sagging but won't help with axle wrap. Instead, you will want the RoadActive Suspension Custom Leaf Spring Enhancement Kit item # RAS3611-HD. This system offers 3,000 lbs in support for your truck's rear end. You can adjust the tension of these springs to fine tune the comfort of your ride. These will...
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  • What Can be Used to Substitute Adjustment Discs for Roadactive Kit
    Hey John, I attached a link to the install instructions for the Roadactive kit part # RAS3611-HD for you to check out. You might need to scroll further down on the page to find them. While we don't have the replacement discs we can definitely still help as RAS has told us that you can use a quarter to replace the black discs and a dime for the white ones. Would that work for you?
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  • Choosing Between Timbren SES and RoadActive Kit for 2022 Silverado 2500 Towing 5th wheel
    Hey David! As long as you don't go over the 3,000 lb capacity I recommend the RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-HD. The RAS is nice because it won't have a negative impact on your unloaded ride quality. It can also be adjusted if need be. If you think you'll be over 3,000 lbs the Timbren SES # TGMRCK25D is a better choice. However, these have a tendency to give you a harsh ride when you aren't towing or hauling. If you need the higher capacity and want...
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  • Will RoadActive Suspension Fit 1975 Ford F-250
    Hi Derek; it looks like that was the stock size for the 73-79 F-250 leaf springs so the RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-HD will fit. Are you adding these for towing or just some extra support?
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  • Could RoadActive Suspension Kit be Used on 2000 Ford F-150 with Add a Leaf to Rear Springs
    The RoadActive Suspension # RAS4612 hasn't been tested on your 2000 Ford F-150 with added leafs to the rear suspension. There's a chance it might work, but there's also a large chance you'd have to remove the added leafs to be able to install this. This would give more support than the added leafs anyway so either way this will be a good solution for you. Otherwise you can keep the suspension the way it is and use a Timbren kit part # TFR1525HD which is a confirmed fit and will give you...
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  • Will the Roadmaster Active Suspension System Void Factory Warranty on a 2022 Ford F-150
    Hey Jeff, no, installing the Roadmaster Active Suspension system like # RAS3611-HD on your F-150 will not void your factory warranty, as long as the installation is done properly and the system does not cause damage to other components. If you have any other questions, feel free to drop a comment and let me know.
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  • Can Roadactive System be Used with 2022 GMC Sierra 2500 with Firestone Air Bag Kit
    Hey David, yes the RAS kit part # RAS3611-HD will fit your 2022 GMC Sierra 2500 that has the Firestone air bag kit currently but typically if you are needing two suspension enhancement kits it's because the vehicle is getting overloaded. The RAS kits are my favorite though. If I was going to pick one system to use that would be what I would go with.
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  • RoadActive Suspension Leaf Spring Enhancement Kit For 2021 Ford F-150 2WD
    Hello Alexander, thanks for getting in touch. We do have a RoadActive Suspension Custom Leaf Spring Enhancement Kit that will fit your 2021 Ford F-150 2WD. It is a slightly different part number for the 2WD kit but we do have it. Here is what you will need: - RoadActive Suspension Custom Leaf Spring Enhancement Kit - Heavy Duty # RAS3611-HD
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  • Is It A Problem If The RAS Spring And The Leaf Shackle Support Are Just Barely Touching?
    Hello Charles. If the RAS # RAS3611-HD spring and the leaf shackle are just touching it will not be a problem. If they were obstructing each other that would be more of a problem but if they are just lightly touching the system will function just as intended.
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  • Will a RAS Kit Leaf Spring Enhancement Kit Work w/ Air Bags on a 2023 Chevy Silverado 2500HD?
    Hey Dan. Yes, the RoadActive Suspension Custom Leaf Spring Enhancement Kit item # RAS3611-HD will indeed fit your 2023 Chevy Silverado 2500HD with a Airlift air bag kit already installed. Why are you needing two suspension enhancement kits? When we get situations like this it's typically because the vehicle is getting overloaded. You can add this information and any other questions you have where it says Reply to Jerred H and I'll be happy to answer them.
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  • Does Roadactive Kit for 2022 Ford F-150 Come with Bump Stop Spacer
    Hey Dalton, the RoadActive Kit part # RAS3611-HD that you referenced does not come with any spacers for the bump stops as it does not interact with the bump stop at all.
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  • Rear Suspension Enhancement Recommendation for 1996 Ford F-350 Dually
    Hey Tom, I checked out your Sulastic shackles and the Roadactive kit part # RAS3611-HD that is a confirmed fit for your 1996 Ford F-350 and it would work just fine with them. Even if you didn't have those shackles this would be the kit I would recommend as we have found it has the best performance without any downsides commonly associated with suspension enhancement kits. Are you towing a trailer?
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  • Suspension Enhancement for 2025 Chevy Silverado 2500 that Fits with Curt Rail Kit
    Hey Corey, which specific fifth wheel rail kit did you have installed and also is it the Firestone Ride Rite kit part # F2613 that you had installed? If there's interference there might be a way to fabricate the brackets to fit on the air bag kit but otherwise a better solution is suspension enhancement that won't interfere like the Roadmaster Active Kit part # RAS3611-HD. The RAS kits are my favorite since they are simple, effective, and offer no downside like harsher ride quality etc.
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  • Comparing RoadActive Suspension Kits for a 2024 GMC Sierra 2500 4WD
    The difference between the RoadActive Suspension kits that fit your 2024 GMC Sierra 2500 have to do with the weight capacity and whether or not your vehicle has the factory top overload springs: - 2K # RAS3611 - 3K # RAS3611-CHD (with top overload springs) - 3K # RAS3611-HD (without top overload springs) If you can go with the higher weight rating I recommend doing so, otherwise you can just use the 2K kit and you'll be just fine.
    view full answer...
  • How to Choose Correct Bracket Mounting Hole for 2024 Chevy Silverado 3500 RoadActive Suspension Kit
    You are correct, the different holes on the RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-HD bracket are there to give you the best fitment on your 2024 Chevy Silverado 3500. There isn't a set bracket hole for each vehicle since the goal is more about just making sure the bolt is located just on the other side of the further U-Bolt for the OEM suspension (see attached for example). As long as you take this approach you'll be good to go!
    view full answer...
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Info for this part was:

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