Toyota Tundra 1999 - 2021 SD Kit

Each RAS® RoadActive Suspension kit consists of a set of two very powerful, coil tension springs that when installed support and assist the rear leaf springs by holding them in their (Original designed) bowed position. When downward strain from load or vehicle weight shift is applied to the leaf springs, the stabilizing action of RAS comes into action immediately absorbing the force of the load. The greater the strain, the more corrective counter assistance force is applied from the RAS spring.

RoadActive Suspension (RAS) is designed to greatly improve the way a truck handles towing or hauling heavy loads. However, RAS® does not increase the payload capacity of a pickup truck.

Payload capacity is determined by the manufacturer and is based on the weight of the vehicle, including its frame, body, engine, fuel, passengers, and cargo. This weight capacity cannot be increased by adding aftermarket suspension components like RAS®.

RAS® can, however, improve suspension strength by up to 50% and help distribute the weight of the payload more evenly across the truck's suspension, which can improve handling and stability while driving with a heavy load. It can also help reduce sagging of the rear end of the truck when carrying a heavy load, which can improve the truck's overall appearance and handling.

RAS® does not increase overall GVWR or payload capacity. It is not designed for trucks that exceed, and it is important to follow manufacturer weight ratings.

While RAS® is geared towards significantly improving overall load handling, stability, and performance without hassle -- one of the most noticeable benefits is reducing rear squat when towing or hauling. Because the RAS works in conjunction with the existing leaf springs (that vary greatly in rating), the amount the RAS reduces rear squat will vary as well. Generally, a pickup owner experiencing 2-3 inches of squat should expect the RAS to keep that truck level or extremely close to level. For vehicles experiencing over the 2-3 inches of squat, RAS will still help and an improvement should still be seen, but remaining perfectly level should not be expected.

Many new full-size truck come with a factory top overload spring. In this case, the overload spring must be removed as described in fitting instructions, for fitment of RAS®.

Removing the overload and replacing with RAS® will provide a slight improvement in suspension strength vs stock. No suspension strengh will be lost. The benefits of replacing the factory overload for the RAS® system include; the RAS® system engages immediately, reduced excessive rebound, improved stability, and better overall ride quality at all times.

RAS®work great in conjunction with a Weight Distribution or Equilizer Hitch. If the WDH/Equalizer has been in use prior to installing RAS, a slight readjustment on the WDH/ Equalizer to add a bit more weight towards the rear of the truck (back onto to the hitch) is often optimal.

RoadActive Suspension kit specs are based off of stock vehicles, without any aftermarket suspension modifications. From a fitment standpoint, RAS generally fits lifted trucks without an issue. An issue may arise if the lift block is fabricated in an odd shape that interferes with our axle connecting brackets, or if it's a complete suspension swap. Before ordering a RAS for your lifted or leveled truck, be sure to check your suspension to look for possible issues as described. If there appears to be an issue as described in either one of these two instances, email us at sales@activesuspension for assistance and further instruction. RAS® can have great benefit on lifted trucks from functionality standpoint, greatly reducing squat caused by towing, significantly improving stability, excessive bounce and any axle wrap/wheel hop.

Just call our Technical Support line Toll Free at 1-800-398-5036 and a member of our support team will answer all of you questions.

RAS is very easy to install and should take about an hour. Fully assembled out of the box with a set of easy to follow step-by-step fitting instructions, complete with pictures! For ease of install you will require a two post auto lift and standard shop tools. RAS can also be installed on the ground using a trolley jack and jack stands.

Yes. RAS® improves traction by reducing axle wrap and the resulting wheel hop. RAS absorbs the added force of increased torque thereby limiting the S-Curve twisting and subsequent release common to leaf springs. Traction is now increased allowing the rear tires to transfer torque to the ground more efficiently.

Yes. RAS® will greatly reduce body sway and roll in cornering. The system's powerful coil spring supports the weight that shifts onto the rear leaf spring that is taking the additional load. Holding the leaf spring in a bowed position (not allowing to flatten out) maintains a more level vehicle on turns and curves.

No. RAS will not harden ride, and in fact, will improve it. Unlike other load assisting products that resist and/or transfer load to the vehicle’s frame, RAS is unique in that it is integrated with your suspension system. The key is in the powerful, variable rated, coil springs which add strength without stiffness. They convert your PASSIVE suspension into an ACTIVE suspension system which vastly decreases rebound felt when going over poor road surfaces.

We have two options! You can go to our "Contact" page here to contact our Canadian Distributor OR purchase directly from our website. Please note that shipping costs can be quite costly when shipping direct.

While the installation of our kits are considered simple and among the easiest in the industry, RoadActive Suspension dealers possess installation experience and industry knowledge for those more comfortable with professional installation. Click here to find a dealer near you.

RoadActive Suspension will often work in tandem with airbags, fitment will depend on the location of the airbag in relation to where our product sits. To find out if it will work for your specific setup, please email sales@activesuspension.com.

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.

Yes, RoadActive Suspension does typically raise the rear unloaded ride height by .5''- 1.5''. The exact amount will vary based on the vehicle, condition of the leaf springs, the kit part number and most importantly the tension set on the spring upon initial install.

Axle wrap occurs when the rotational force of the tires causes the axlehousing to twist or rotate. This rotation forces the springs to bend into an S-shape. When the axlehousing rotates far enough, forces cause the tires to loose traction, and jump, or "hop". Once traction is lost, the springs snap back into their original positions.

RAS® effectively reduces axle wrap and wheel hop by "absorbing" the added force of increased torque while holding the leaf springs in their original bowed shape. The S-shape twisting, and subsequent hop, is thereby greatly reduced. Traction is increased because tires transfer torque to the ground efficiently.