Ford F-350 2011 - 2026 | Mega Duty Kit
Ford F-350 2011 - 2026 | Mega Duty Kit
Ford F-350 2011 - 2026 | Mega Duty Kit
Ford F-350 2011 - 2026 | Mega Duty Kit
Ford F-350 2011 - 2026 | Mega Duty Kit

Ford F-350 2011 - 2026 | Mega Duty Kit

SKU: 3611-SLMD

Regular price$649.00
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Shipping calculated at checkout.

Fitment

Checking fitment for your active vehicle...

Factory Overload Spring
  • In stock, ready to ship
  • Backordered, shipping soon
*Temporarily sold out. Estimated availability: ~2 weeks.
  • 1-3 Day Free Ground Shipping 1-3 Day Free Ground Shipping i
  • 5 year warranty 5 year warranty i

Get the best of both worlds with RoadActive Suspension® Mega-Duty — our strongest suspension upgrade engineered for heavy payloads, serious towing, and demanding truck applications.

Mega-Duty strengthens your factory leaf springs by up to 50% while improving unloaded ride quality, handling, and overall control — without the hassle or maintenance of airbags.

Designed for 3/4-ton and 1-ton trucks that tow and haul regularly, RAS® Mega-Duty helps reduce:

• Up to 2" of squat
• Excessive bounce & body roll
• Sway & axle wrap

Independently tested at the Transportation Research Center (TRC):

• 23% reduction in road transmissibility
• 43% improvement in pitch stability
• Approximately 30% stronger spring rate than HD

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 with zero maintenance required.

If truck has factory overload spring, top overload spring must be removed for installation of RAS. Mega-Duty will provide more strength than the factory overload spring.

If you're squatting with your F-350 — Mega-Duty is the answer.

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.