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
Highlights
Custom Fit for Your Vehicle: Mounts to existing attachment points
3,000-lb Load Support: Levels your truck under heavy loads for safer towing and steadier handling.
Improved Stability and Control: Reduces sway, body roll, and bounce for a more confident drive.
No Maintenance Needed: Once installed, there’s nothing to adjust or monitor over time.
Prevents Axle Wrap and Wheel Hop: Keeps traction smooth for better braking and acceleration.
Easy Bolt-On Setup: Installs quickly with no drilling or welding, saving time in the driveway.
Features to know about
Keep the Truck Level and Confident: 3,000-lb Heavy-Duty Suspension Support
When the rear end starts to sag under a trailer or heavy load, steering and braking can get sketchy. The RoadActive Suspension Custom Leaf Spring Enhancement Kit adds up to 3,000 lbs of load-leveling support that automatically adjusts to your load. The variable-rated coil tension springs engage as soon as weight hits the bed, keeping your ride level front to back and preventing squat or bottoming out. That means better control while towing or hauling without stiffening the ride when unloaded.
Cut Out Sway and Body Roll: Mechanically Active Leaf Spring Design
Hauling a camper or boat can make the truck feel like it’s leaning through turns or rocking in crosswinds. This system strengthens your factory leaf springs so they stay bowed instead of flattening out under pressure. The mechanically active coils react instantly to weight transfer, stopping sway and body roll before they start. It feels more stable in curves, on uneven roads, or when passing semis—almost like adding a built-in sway bar without extra hardware.
Stop Axle Wrap and Wheel Hop: Instant Traction Under Load
Heavy torque or steep grades can twist the leaf springs into an S-shape and cause wheel hop. The RAS kit locks out that flex by holding the springs in position with its tensioned coils and brackets clamped around the factory U-bolts. That eliminates axle wrap so your tires stay planted for smoother acceleration and braking. You get stronger traction and less stress on shocks, shackles, and tires every time you load up.
Set It Once and Forget It: Adjustable, Maintenance-Free Design
There’s no air pressure to monitor or bags to leak here. Each coil spring is adjustable during install using included spacers for a custom fit—tighten for more support or back off for a softer ride. Once set, the system needs no maintenance or re-adjustment. The fully assembled units bolt on with no drilling or welding, using corrosion-resistant epoxy e-coated steel rated for more than 800 hours of salt spray testing. It’s a straightforward upgrade that keeps working as long as you do.
Specs
Weight and Capacity
Weight capacity: 3,000 lbs
Note: RoadActive Suspension will not increase your vehicle's weight-carrying capacity
Warranty
Warranty: 5-Year warranty
Money-Back Guarantee: 30-Day money-back guarantee
3611-SLHD RAS Custom HD Active Suspension System for OEM Leaf Springs - Rear Axle
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.
by: Nick 04/15/2021
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by: Russell09/17/2022
1412366
by: Wendy 09/05/2022
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by: Richard 09/23/2023
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by: Clint 03/23/2023
1542057
by: Alex 08/25/2022
Outstanding quality fast delivery. 1375424
by: Toby 01/31/2022
Easy install and really reduced squat! 1255956
by: Alex 07/15/2021
Install took about 30min. Seems my rear is a hair higher at 25%. Going to tow 7k about 650mi this weekend. See how much if helps.1094487
by: Kyle05/07/2023
Pretty bouncy, not as good as other opt ions.1572960
by: David 10/05/2022
Made a huge difference in the way my truck sits with a 12,000 lb. RV on it1439065
by: David 04/25/2021
Great improvement. Much more stable and level towing my 8000 pound travel trailer with my 2016 F250.1021646
by: Stacy 05/05/2023
I really like these. I have a pair on both my trucks. They don't take away all the bouncing, but they take a whole lot of the bouncing away.1571927
by: JohnW10/17/2019
Installing was not difficult, not as much sag when connected to 1080lb tongue weight trailer718265
by: Robert 03/13/2024
So far I like the product it comes with good instructions and easy to install . Also the ride of the truck is better than the airbags I had a lot smoother and not so bouncy .1746709
by: Michael11/16/2021
Well I just installed them today so I went ahead and loaded my excavator just to see how much the rear of my truck squatted and it didn’t squat near as much as before, I’m pulling 16000 lbs trailer and excavator with a 2020 F250 super duty and before I installed I normally would have to park my excavator in just the right spot to give me enough tongue weight that I needed but I always had that seat of the pants feeling that I didn’t like while towing it, drove down the road with everything installed and loaded and it honestly felt like a completely different truck, didnt pull it but about 4 miles but so far so good, think I’ve finally found my solution1205056
by: Steven05/03/2023
I use it with my Timbrens and it give the truck a great ride when not towing. It also seems to help the Timbrens with a relaxed reflex response to dips and bumps when towing. I'm very happy with it.1569861
by: Doug D06/07/2019
Great product! It does what it advertises and is a breeze to install on my F-150 but a little harder on the 350 since you have to remove the overload spring. Works great helps keep truck perfectly level when towing my 10k lb trailer. Highly recommend. 654976
by: Gerald 08/26/2023
This is the 2nd pair I purchased. My first was for a 2017 Ford F150 and the first thig I did when I purchased my 2021 F250 Super Duty was to get a pair for that truck. I don't know that I will ever have a truck without a Leaf Spring Enhancement Kit.1655091
by: Jeffrey03/21/2026
The description was misleading. I thought I was getting a system that can be used with my factory overloads, that was not the case the instructions wanted me to remove the factory overload springs3507524
Mike L.
3/25/2026
I'm sorry for the confusion, Jeffrey. We mention in our fitguide (where you look up fits for your year/make/model vehicle) that 'Application requires permanent removal of top overload springs (if equipped)'.
by: Blake04/15/2025
The product did what it was advertised! Now see how long it will last. Installation instructions not the best!3300580
by: Daniel 01/14/2025
When I ordered the RAS , I was told that it would fit in place even with my existing Firestone Air spring , and the brackets from the RAS don’t pass beside the air suspension !3250928
by: Michael 02/10/2025
An excellent solution for leveling my tow vehicle! The road active suspension system definitely improved both the ride and the leveling of my vehicle!3262424
by: Alexis12/03/2025
Feels like a whole new truck notice most turning holding road with out skipping on fast moves. Truck doesn’t stoop with heavy trailer 16000#+3457288
by: Shane02/15/2023
Really like this product. Was super easy to install and instructions were easy to read. Amy was very helpful in recommending the correct part and even took the order for me. Its winter here in the Rockies so I haven't had a chance to test out the load of my 5th wheel, but the ride still feels smooth. I have ordered from etrailer before and always have a good experience. Choose them with peace of mind.1518946
The Road Active Suspension Custom Leaf Spring Enhancement Kit - Heavy Duty was installed on a 2025 F350. What I did not care for is that to install this you must omit the factory overload spring. This was not made clear if at all before purchase. Did we get any benefit from Road Active Suspension no.3476826
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See what our Experts say about this RAS Vehicle Suspension
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... view full answer...
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... view full answer...
Hey Tony, if you are wanting additional suspension support and are concerned about ride quality at all the best solution is the Roadactive Suspension Kit part # RAS3611-SLHD as this is only option that will give the additional support you are looking for and actually improves ride quality. This can provide up to 3,000 lbs of additional suspension support to what your vehicle has currently.
If maximum support is desired and ride quality is not a concern then Timbren Severe Service kit... view full answer...
Hey Dennis, we have just what you are looking for with the Roadactive Suspension Kit part # RAS3611-SLHD that is a fit for your 2016 Ford F-250 Super Duty. This is only option that gives you the additional support you are looking for as well as doesn't hurt ride quality loaded or and unloaded and also improves handling. I have friends with this on their truck who have used other products like air bags or Timbrens and they swear this is the best. view full answer...
Hello Ross,
Thanks for writing in, great question!
For your 2024 Ford F-350, the correct RoadActive Suspension kit depends on whether your truck has the factory top overload spring on the rear leaf spring pack.
If your truck has the factory top overload spring, you'll want the RoadActive Suspension Custom Leaf Spring Enhancement Kit - Super Heavy Duty, # RAS3611-SLHD. If it does not have the factory top overload spring, the correct kit is the RoadActive Suspension Custom Leaf Spring... view full answer...
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. view full answer...
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... view full answer...
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... view full answer...
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... view full answer...
Hey Peter, so you can definitely use the Firestone Ride Rite kit part # F95FV on your 2023 Ford F-250 with the Equalizer WD system part # EQ37120ET you have. This will give you additional suspension support but these kits are actually harsher than what you'd think with air bags.
Instead what I would recommend is the Roadactive kit part # RAS3611-SLHD as this gives you additional support like you are wanting but it actually improves loaded and unloaded ride quality unlike every other option.... view full answer...
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... view full answer...
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. view full answer...
Hi John,
So you're actually going to have to remove the top overload spring of your 2000 Ford F-250 because they physically occupy the same space as the RAS. I checked directly with RoadActive for you, and the correct part for your truck is actually the RoadActive Suspension Custom Leaf Spring Enhancement Kit # RAS3611-LHD.
This kit includes spacer plates that you put back at the axle so that you will have the same U-bolt thread. As for the # RAS3611-SLHD, it has extension brackets that... view full answer...
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... view full answer...
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... view full answer...
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... view full answer...
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. view full answer...
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... view full answer...
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... view full answer...
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. view full answer...
I spoke to my contact at Timbren about the Timbren Rear Suspension Enhancement System part # TFR250SDG for your 2012 Ford F-250 and they informed me that the upper metal bracket cannot be removed. Therefore, the bump stop cannot be directly attached to the frame without this bracket.
I have two options for you. You can use a shorter bump stop that will reduce the occurrence of the bump stops engaging. For this you would want to use the Replacement Rubber Spring for Timbren Rear Susp Enhance... view full answer...
The RAS system # RAS3611-SLHD sits on your 2014 Ford F-250's leaf springs and wouldn't interfere with the Timbrens that you currently have installed. It will most likely be a bit of a pain get the RAS in place because the Timbrens sit close to the spring stack, but both can be used together without issue. view full answer...
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... view full answer...
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...
At etrailer we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.
Mike L.
3/25/2026
I'm sorry for the confusion, Jeffrey. We mention in our fitguide (where you look up fits for your year/make/model vehicle) that 'Application requires permanent removal of top overload springs (if equipped)'.