Carli Suspension 1-Inch Lift XXHD Progressive Leaf Spring Kit; +3500 lbs. (17-24 4WD 6.7L Powerstroke F-350 Super Duty)Find parts that fit my vehicle

Reduced Overall Spring Rate to “light 3/4-ton” for a Better Ride (more on capacity HERE)
Increased Progression (Spring Rate)
Progressive Overload (Factory overload is a hard-stop)
Dramatically Increased Suspension Travel
Elimination of Factory Vulcanized Bushing Bind – Added Ability to Service Cari Bushings
Maximized Spring Efficiency by Minimizing Friction Throughout the Pack
Custom Tuned Commuter, Backcountry, Pintop and E-Venture Shock Packages to the New Rate and Progression of the Carli Leaf Springs
Optimized Center Pin Location to Ensure Maximum Tire Fitment
Military Wrap on Front Eyelet for Safety
Sprayed, OEM Quality Coating Tested to 250 Hour Salt-Spray. The coating is applied to each leaf before assembly to ensure complete coverage.
FACTORY LEAF SPRINGS
Knowing whether to swap leaf springs starts by understanding what’s on the truck and the shortcomings of the design. The factory springs do one thing well – haul. They’re designed and built to handle the max capacity of the truck every day of the truck’s life and, when loaded with max capacity, they ride decent. Thing is, most of these trucks sell to people that will use the HD truck for its intended purpose, but far less frequently than the design intends.

Leaf springs are archaic in design – they either haul well or ride well. You can land anywhere in this spectrum you’d like but there will be sacrifices at the opposite end as you shift throughout. The factory springs slide the scale all the way to the “haul well” end of the spectrum. Let’s dig into their design…

The factory leaf spring are designed with 2-3 stages of spring rate. Pictured is a Stock F250 Leaf Spring Pack with 2 stages.



MAIN SPRING
First, there are 2-4 springs that make up the main support in the factory pack. These are high-gauge steel and ride, well, like high gauge steel. F250 High-Capacity/Tremor Leaf Springs or F350 Springs will have 3 main springs AND an upper overload (adding a 3rd stage of spring rate in the pack).

Pictured is an unloaded pack; under the weight of your truck bed, you’ll see less of a gap between the main springs and the overload.


OVERLOAD
The second stage of the pack is the below-highlighted lower overload spring. Providing support to the main springs, this immobile spring rate ceiling ensures the rear doesn’t sag below a predetermined point under load. As there is very little give to this spring, you’ll know when you bonce off the overload. Riding around town, you’ll likely note that small bumps are absorbed pretty well as you’re riding on the leaf spring bushings and main springs (F250, at least – F350 are pretty stiff everywhere thanks to the 3rd main leaf).

If you encounter a speed bump or culvert, especially at speed, the rear end hits much harder and often jumps up in the air as a result of the engagement of the lower overload spring. This design is cheap and proven on an HD truck. Unfortunately, it leaves a lot to be desired in ride quality, on and off-road, in the medium to large bumps, particularly when unloaded as there’s not enough weight in the bed, nor rebound valving in the shocks, to keep the rear planted.



CARLI LEAF SPRINGS
Carli aimed to design a leaf spring pack that would provide a more supple and planted ride with only a slight reduction from a standard 3/4-ton load capacity. Rather than built to haul, they’re designed with an emphasis on ride quality and consideration for capacity. In the “haul well” to “ride well” spectrum, we center the springs to ensure they’re still capable of hauling a capacity respective to the 3/4 to 1-ton platform (albeit, less than the factory springs), but ride much better.

We do this as there are load supplements available to ensure one can safely max the truck’s capacity when their use-case demands it, even with reduced rate leaf springs. Potentially improving ones hauling situation even relative to factor

Fitment:

• 2022 Ford F-350
• 2023 Ford F-350
• 2024 Ford F-350

Details

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