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Get the best of both worlds with RoadActive Suspension® HD — the only suspension upgrade that strengthens your factory leaf springs by up to 50% while improving unloaded ride quality, handling, and overall control.
Unlike suspension upgrades that require constant adjustment, maintenance, or compromise everyday comfort, RAS® HD reduces squat, excessive bounce, sway, and body roll without the hassle of airbags or harsh unloaded ride quality.
This fully mechanical 3-in-1 system combines the benefits of a helper spring, sway bar, and traction bar into one simple bolt-on upgrade designed for trucks that tow, haul, and drive loaded regularly.
Helps provide:
• Up to 50% increase in rear suspension strength • Up to 2" reduction in squat • Improved towing & hauling stability • Reduced sway, bounce, and axle wrap • Same-as or improved unloaded ride quality
With a quick 1-hour installation and zero maintenance, RAS® HD is one of the simplest and most effective ways to improve towing, hauling, and everyday driving performance.
Watch Installation Video1–2 Day In-Network Ground Shipping FREE
Transit estimates shown. Actual delivery times may vary.
RoadActive Suspension provides a 30 day money back guarantee, from date of purchase. However should the kit be returned, it must be re packed in the original packaging with all components included. On orders with free shipping (where shipping was paid for by RoadActive Suspension), refunds will reflect the invoiced amount, minus that shipping cost billed to us by our shipping provider. In addition, the customer will be responsible for the return freight charges.
It works with your suspension — not against it.
Each kit is tailored to your specific vehicle
RoadActive Suspension is uniquely assembled for your model and typically ships within 1-2 business days! RoadActive Suspension is the only suspension upgrade on the market that adds strength to your rear suspension, provides same as or better than stock unloaded ride quality and doesn’t require readjustments or maintenance.
Each RAS kit comes fully assembled out of the box and ready for installation. Follow your application guide that is in the box and you will be ready to test your RoadActive Suspension after an installation as simple as 45 minutes! If you are not satisfied with your RoadActive suspension we offer a money back guarantee.
Reduce Rear Squat & Bounce
Improve Stability
Improve Roadhandling & Stability
Make RVing Safer
Reduce Axle Wrap
No Readjustments or Maintenance
We already know what you're going to ask.
No, installing RoadActive Suspension (or any other rear suspension helper) does not automatically void the factory warranty. The Magnuson Moss Act states that it is illegal for a vehicle manufactuer or dealership to void a warranty just because a part has been installed. The manufacturer or dealership may only void the warranty if they are able to prove the aftermarket part caused or contributed damage to the vehicle. Even then, warranty to the impacted component(s) is the only portion of the warranty that may be voided. In this case, all other parts of the vehicle remain under warranty.
RAS uses a variable-rate tension coil spring that attaches directly to your rear leaf springs. It works like a muscle, progressively engaging as load or force is applied. This keeps the leaf springs in an upright bowed position to prevent sag, improve stability, and enhance bounce isolation.
Most applications see a 2–3" reduction in rear squat. The exact amount will depend on multiple factors such as vehicle size, load size, load placement, leaf spring condition, and the tension setting of the RAS.
Expect same-as or better-than-stock unloaded ride with less bounce and more control.
Yes — in as little as 45–60 minutes with jack stands and hand tools. No drilling, no air lines, no maintenance.
Airbags add complexity, cost, and ongoing maintenance. Other helper springs only address sag and can compromise ride comfort.RAS is 3-in-1:it controls squat, reduces sway, and improves traction — all with zero maintenance.
Customer Reviews
Overall rating: 4.7 / 5 from 195 reviews.
Just installed the RAS on my 2015 Toyota Tundra Crewmax! Super simple install without any issues. It’s only been a week but I already notice a significant difference in the ride while towing, the truck just seems to anticipate the road ahead. Looking forward to a long haul coming in November!
I have a Tundra TRD PRO which has a softer suspension than other tundras. I added the RAS and it has made a HUGE difference in towing my boat and the squat. I couldn’t be happier with it!
Love RAS. I was introduced to it by someone who had bags and switched after having issues with leaking. I’m so glad I found this system for my Tundra. Super easy to install!
2011 Toyota Tundra Double Cab 2WD
Using the 25% tension spacer, I gained 1" of rear lift, when combined with the Eibach Stage 2 rear shocks, the lift totaled 1.75". Having tested the system both without load and under load, I can verify a few things.
Unloaded, the ride quality is only improved. No notable extra stiffness in ride, but definite improvement in bump compliance and cornering. The difference in braking response alone is night and day. You may not realize just how much axle wrap is occurring when braking without this system, but you will certainly notice after installation.
Loaded under approximately 3-4k lbs, which would previously have left my rear end sagging by 1-2", there is now no noticble sag at all. Possibly 1/4". If I planned on hauling upwards of 7-8k lbs regularly, I would increase the tension to 40%.
Installation was a breeze. Quick rundown:
1. Floor jack
2 Jack stands
3. Remove wheels
4. Unbolt rear shackles
5. Install RAS
6. Reinstall rear shackles
7. Dial in tension with included spacer(s)
8. Reinstall wheels
It could reasonably be done in about 45 minutes, but expect closer to a few hours if you aren't experienced in working on suspension. Easily installed by anyone with the want to do so.
10/10 product. Works exactly as advertised and will most likely serve most people better than helper springs or thicker leaf packs for most applications. It should honestly come factory installed on any truck with leaf springs.
2001 Toyota tundra 4.7 L V8, 2 Wheel Dr.
made an eighth 10 pick up truck into a half ton pick up truck, I needed it years ago handles much better on curves and corners. Still rides like a dream!
Easy install, smooth ride while towing and unloaded. This kit showed up a couple days before a 400 mile round trip to haul a car. Took about an hour to install and it totally changed the comfort and stability of the truck while towing. I’d recommend this to anyone who tows with their half ton pickup.
Installing these was quick and easy to set per the instructions. Put the Toyota Tundra 1999 - 2021 | HD Kit on my 2020 toyota tundra. Already feel the difference and really changed the feel of a 20' cargo trailer loaded while towing.
2021 Tundra 2wd towing 6700 pound camper. Just completed 13 hour round trip. Rock solid, even at 80 mph. Oops. Vast improvement over stock. Ride is nice with no load as well. Highly recommend. Easy install.
Should have went with airbags! I hear they have a mega option now that might support weight better but I shouldn’t have needed that. Only 700 lbs tongue weight and it sags almost as bad as with out. Little more stability but not worth the price tag.
2015 Toyota TRD Pro. Was just a little soft in supporting towing in the rear. While capable with the squat, it seemed too much. Aesthetically goofy looking too. Tried the bigger bump stops with no luck. RAS nailed it. I set it on the gray spacer for about 40% more capacity. I expected a rougher ride, but happily it was a smoother and more intentional response, no rattle over bumps. Towed my TT twice with it and I'm very happy!
First time using and installing the RAS on my 21 Tundra. Really easy install for this novice. It has improved the ride even when empty! Great product, worth the money!
Truck still rides nice, a little firmer unloaded . I personally think the ride is much nicer, definitely don’t feel the body roll or sway when driving unloaded. I haven’t pulled a trailer of
any size, but with three adults sitting on the tailgate it barely squats now. So far, I’m very pleased.
Store owner replied:
Hi Steven, thank you for choosing RAS and leaving your feedback! Please note that the axle connecting bracket shown in the picture is installed upside down. A technical support rep will be reaching out to you shortly! Thank you.
'18 Tundra Crew Max. One of the best mods I've done to my truck. Really improved the ride quality. Don't pass up this mod.
Extremely easy to install and the instructions couldn't be more simpler. Raised my 2016 Trundra from 39" at the rear wheel well to 41.5" when empty with new tires and fresh alignment. Once I hooked up to my 29' camper the truck only dropped to 38" when normally it would drop to 35" to 36". The truck and loaded camper were perfectly level, no nore sag, no waggle and no more excessive bouncing when driving over RR tracks. Empty or loaded.
Amazing, thank you guys for an outstanding product.
2020 Tubdra, these would work great if you had a consistent load but for my use I would rather have airbags like my previous truck. I went with RAS with plans of more backcountry driving, however even set on a lighter setup it is still to much and create a stiff ride. Good product and I like the engineering and quality but like I said my use varies to much to get the best of both worlds out of it.
2012 Toyota tundra it was a fairly easy put on for a 70 year-old but it brought my truck up an inch and a half with no weight put the trailer on. It didn’t go down very far and did just what I wanted. It handles better around turns Very pleased with the product.
I was skeptical going in to buying the RAS 4611-TDHD kit for my 2010 Toyota Tundra. I tow a 31ft travel trailer often and before the RAS kit, I was using add-a-leaf helper springs in the rear of my truck to give it the boost it needed to handle my trailer's 1000lb tongue weight. The traditional helper springs did their job while towing, but when unloaded the ride was very bouncy and harsh.
Based on the strength of many reviews and videos, I decided to try the RAS to see if it could provide the strength I need to tow AND a smooth unloaded ride as advertised.
I am pleasantly surprised at how this kit performs. I can tell it does not provide as much overall strength as the traditional helper springs, but it still handles my trailer without bouncing or swaying, and much more importantly- THE RIDE IMPROVEMENT IS AMAZING when unloaded. And let's be real guys, the truck is unloaded 90% of the time at least.
So- as advertised, the RAS does indeed provide better towing control AND a significantly better unloaded ride vs stock leaf springs and vs other forms of helper springs. I'm happy as a clam.
Installed on my 2013 Tundra Rock Warrior. Had quite a bit of rear squat, especially when I hooked up my car trailer. Purchased the Tundra HD kit. Install was pretty straightforward. My truck has much better stance and rides much better, no more squat.
Shipping was very fast. I installed these in about an 1-1/2 hours ( I’m older so I move slower) my first setting was at the 40% additional load, my 2021 Tundra rode too stiff for me. Changed to the 25% additional load setting and the unloaded ride was close to factory original ride. The install did raise the rear a little and gave it a slight firmer ride. Towed my camper (7000 pounds) and was really impressed, truck was level camper was level and bounce was almost eliminated. So glad that I installed the RAS system
I bought the heavy duty RAS for my 2021 Tundra. I’m 67 and reasonably skilled. The installation was easier than expected. The most difficult step was removing a bracket on the rear leaf spring.
I set up the RAS to the heavy duty setting per the instructions. The ride on my Tundra improved without any cargo or trailer attached. With about 500# of cargo the ride was more stable and smoother. I’m very impressed with the RAS.
These things work great. Little before and after picture. The one that is squatting obviously is before with an empty trailer. The one that is level possibly a bit higher is with the HD kit installed and the trailer has 40 gallons of water in the tank up front.
I have been wanting to upgrade my suspension for sometime now. I researched all of the different systems and listened to many other Tundra drivers. RAS was always at the top of my list due to cost and benefits of the system. I have not been disappointed. My hitch used to drop 5" when I put my trailer on it with a tongue weight of about 800 lbs. It now sits about an inch higher than stock and it drops 3.5" so I gained 2.5" of ride height when towing. My comfort level has increased dramatically. I have been towing for decades so this is saying something. I am recommending it to all of my friends.
So far so good. I do a lot of beach driving and I just got a camper and put the RAS on. Felt good and stable in the sand. Never took the psi down at all and it went just fine. The rear of the truck only lowers about 2 inches but I'm also right up close to my payload capacity so I wasn't expecting zero sag but you can barely tell when it's all loaded up.
I already had spring helpers on the rear and was worried they would interfere but so far I don't think they are.
I have a 2016 Toyota tundra TRD off road installed the RAS suspension super happy with the results. My thoughts were that it was going to be stiff and it was perfect ride quality I haven’t been able to tow yet, but the truck feels a lot better.
I own a 2021 Tundra TRD Pro and bought the HD spring kit (Kit ID: 4611-TDHD). I got to say, this is the best upgrade I have ever made to a truck. I used to have real bad up and down jarring on some concrete portions of interstate when towing my trailer. These springs have completely fixed that. And it is true that without towing, or weight in the bed, the truck has just as nice of a ride...incredible. I owned a truck with airbags in the past and the ride was rough, even at 5 psi. I also love the 1.5 inch lift. I am truly thankful for this product!
2010 Toyota Tundra. I haul a 6x12 heavy trailer. My back end would drop about 3 inches and I would bottom out on everything before I installed these. My ride is so much smoother and I don't bottom out on anything anymore. Install literally took less than an hour and I couldn't be happier!!
After much research I purchased the 1999-2021 Toyota Tundra HD suspension kit.
With my shell and bed kit the truck bed load was at 300lbs, if I connected a small trailer I would get a sag in the rear.
After installing the RAS System I was able to easily level the truck as needed while not compromising its ride, it actually reduced cornering sway.
2016 Tundra. 7 inch lift 37 tires. Easy install, just lift from hitch- no need to remove tires. White spacer added 1 inch to rear. Towing 21 ft Toyhauler-needed to reduce rear sag
Select your vehicle details to see only matching kits.
Shipping
Fast & Free Shipping
Is Faster Than Ever
With our expanded RAS® warehouse network, most orders reach you in 1–2 business days. Transit times depend on inventory levels and carrier performance.
UPS Ground transit estimates from our network (AK/HI and outlying areas may vary).
How It Works
Orders placed by 3 PM local time for popular part numbers can ship the same or next business day from the nearest in-network location. Delivery estimates are based on UPS Ground service.
Eligible States
Our multi-warehouse setup enables 1–2 day transit to ~98% of the continental U.S.. Alaska, Hawaii, Montana, North Dakota, South Dakota, and some remote regions typically see 3–5 business days.
Eligible Part Numbers
Currently eligible for in-network 1–2 day transit:
3611-YHD
3611-HD
4611-HD
5611-TZHD
4611-TDHD
3611-BHD
36113-THD
3611-SLHD
4614-SAT
4614-SAT
4611
4617-T
3611-Y
Note: Availability varies by SKU and location. Most orders ship same/next business day, but lead times and carrier estimates are not guaranteed.
Ready to Upgrade Your Truck?
Get RoadActive Suspension delivered fast — straight to your door.
RoadActive Suspension, Inc. provides the original retail consumer our Warranty that each new RoadActive Suspension, Inc. product shall be free from defects of material and workmanship, as set forth in this limited Warranty.
Length of Coverage
Except as provided below, RoadActive Suspension, Inc. offers the following duration:
1. RoadActive Suspension, Inc. kits and their components are warrantied in the United States and Canada against defects in workmanship and materials for five (5) years following installation on the vehicle for which the kit is purchased.
2. The Warranty is terminated immediately when you transfer ownership of the vehicle to a second party, or it is used for a purpose not intended, regardless of your consent and/or if the product is installed on a second vehicle, regardless of when the second installation takes place. Because of these provisions, the Warranty is not transferable.
Authorized Sellers Only
Warranty coverage applies only to products purchased directly from RoadActive Suspension, Inc. or from an authorized RAS dealer or retailer. Purchases made from unauthorized resellers or third-party sellers (including online marketplaces) may not qualify for warranty coverage.
Obligations
RoadActive Suspension, Inc. shall be limited to replacing or repairing, free of charge, any part or parts that reasonably appear to us upon inspection to have been defective in material and/or workmanship. You will be responsible for the cost of transportation charges and any charges in connection with reinstallation of the defective parts.
Exclusions and Limitations
The limited Warranty does not cover and RoadActive Suspension, Inc. will not be held responsible for any costs or injury you sustain by reason of the following:
1. Parts and labor necessary for removal, reinstallation, vehicle modification, or any vehicle repair, service, or replacement, and repair of defective parts other than RoadActive Suspension, Inc. defective parts, regardless of cause.
2. Any repair or replacement made necessary by any accident, breakdown, or failure of bolts, nuts, washers, or any other parts used to install the products, whether or not by RoadActive Suspension, Inc.
3. Unreasonable use, failure to install or maintain the product properly, modification of the product, or failure attributed to a defect in the vehicle, towing, fire, theft, environmental condition, or negligence, accidental or intentional damage or destruction.
4. Incidental or consequential damages, including but not limited to compensation for loss of use of the product or vehicle, inconvenience, lost profit, or any other direct or indirect loss.
Individual Components Policy
For liability and safety reasons, RoadActive Suspension, Inc. does not sell or distribute individual components of any RAS kit separately. Each RoadActive Suspension kit is designed, tested, and warrantied as a complete system. Replacing or modifying any component independently—including threaded rods, brackets, or hardware—may affect system integrity and void all warranty coverage. Replacement components are only available through approved warranty claims or complete kit purchases.
Non-Warranty Replacement Policy
In cases where damage occurs due to installation error, misuse, or other non-warranty causes, replacement components are available only through the purchase of a new complete RoadActive Suspension kit. Individual components are not sold separately for safety and compliance reasons.
Warranty Void Conditions
This warranty will be considered void if any part of the RoadActive Suspension kit is altered, modified, or installed incorrectly, or if the product is used in any way that differs from its intended purpose. Warranty coverage also becomes void if non-RAS components are substituted or used in conjunction with the system in a way that may affect performance or safety.
Third-Party Modifications
RoadActive Suspension, Inc. is not responsible for any issues or failures that result from the use of aftermarket components, vehicle modifications, or non-standard installations. The RAS system is designed to function only with stock vehicle configurations unless otherwise specified in writing by RoadActive Suspension, Inc.
Inspection Recommendation
As the installation and removal are not covered by this Warranty, we recommend that you inspect the installation of the RoadActive Suspension, Inc. kit to ensure that the product was installed safely and presents, beyond any reasonable doubt, no danger to any other part(s) of the vehicle such as brake lines, gas tank and lines, sewer lines, electrical wiring, or the chassis.
How to Obtain Service
To obtain warranty replacement parts or repair, RoadActive Suspension, Inc. must first be contacted by letter or telephone, providing your name, make, model, and year of vehicle, and evidence of date of installation. Written or verbal approval will be given to you by an authorized RoadActive Suspension, Inc. employee, and you must then return the part to be replaced or repaired—at our option—freight paid, to our warehouse. The replacement part will be shipped within fifteen (15) days following our receipt of the original part.
Be sure to obtain our approval before returning products to our warehouse. They will not be accepted until approval is obtained.
Disclaimer
The above Warranty is the only warranty extended to you by RoadActive Suspension, Inc.
ALL OTHER OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE HEREBY EXCLUDED.
Governing Law
This Limited Warranty shall be governed by and construed in accordance with the laws of the State of North Carolina, without regard to its conflict of law principles. Any disputes arising from this Warranty shall be brought exclusively in the state or federal courts located in Mecklenburg County, North Carolina.
