There are plenty of reasons to like Ford's Super Duty pickup trucks, such as the solid front axles, reliable transmissions, and refined interiors. These trucks really can do it all, from hauling your Jeep to the trail to hauling your family around town. The one area they can use some help though is in the suspension department. It isn't that the front coil spring and radius arm and rear leaf spring design that was first introduced in 2005 is lacking, but Ford has to equip these trucks with a low-slung suspension and small tires in order to maximize fuel economy.

Fortunately, suspension options abound for the Super Duty to fit nearly any size tire you can imagine. Even better is the heavy-duty architecture of the Super Duty can run up to 40-inch tall tires without concern about smoking transmissions or breaking axles. There are so many options, in fact, that putting a new suspension under your Super Duty can be a bit overwhelming. Never fear though, we are here to point you in the right direction so you get exactly the look and the performance you are dreaming of.

A simple leveling kit is all that is needed to clear 35-inch tires on the Ford Super Duty. This one from Pro Comp even reuses the factory front shocks to keep cost to a minimum. Nothing is needed in the rear as the system levels out the truck and doesn't add any lift in the rear.

Bilstein's leveling kit for the Ford Super Duty is a bit more advanced. It supplies 2.5-inces of lift and clears 35s. However, it supplies new coils and shocks for better bump absoprtion. However, it is also a more expensive option than just a basic leveling kit.

How To Fit 35s

Super Duty trucks come with 33-inch tall tires from the factory, so it is pretty easy to bump up to 35-inch tires with minimal modifications. A 2-inch coil spacer, or leveling kit, is all that is needed to fit 35-inch tall tires. The rear suspension actually requires no modifications at all. Note that most 35-inch tires are considerably wider than the factory offerings, though. Wider wheels with the appropriate offset (0mm offset for an 8.5-inch wide wheel, or -12mm offset for a 9-inch wide wheel) are necessary to provide even tire wear and prevent tire rubbing at full steering lock.

Going with a 35-inch tire is an excellent option for those that want a bit more performance in the dirt, but still want to use their truck. They don't have much of a negative impact on towing and you will probably be fine with the stock gears. Since you don't have to run much lift to fit them, it is still easy to get in the bed of the truck too.

While 37-inch tall tires aren't much taller than 35s, they do require more components to run on a Super Duty safely. These include not only taller springs but radius arm mounts, longer shocks, extended sway bar end links, and more.

How To Fit 37s

While 37-inch tires are only two inches larger than 35s, they do require significantly more work to fit. A lift raises the truck vertically, but the concern is the tires hitting at the front and rear of the wheel well during turning and/or articulation. This means that while you can fit 35s with just a leveling kit, we recommend a full 4-inch suspension lift to clear 37s. Quality suspension systems at this height will include components such as drop brackets for the track bar and radius arms, a drop pitman arm, new coil springs, all new shocks, extended brake lines, and more. All those parts add up in price, but trying to take shortcuts and just running taller coils results in poor geometry that wanders on the road and can be a handful in the dirt. A 4-inch lift and 37s not only look great on a Super Duty, they strike a great balance between off-road capability, towing, and daily driving.

Ford's radius arm setup on the Ford Super Duty is okay for street use, but inhibits articulation in the dirt. If you plan to hit the trail, a four-link conversion is the way to go.

There is no denying that Ford Super Duty on 40-inch tires looks amazing. Fitting the big tires is going to require an 8-inch lift and you should also plan on re-gearing as well.

How To Fit 40s

If you really want to stand out from the crowd 40-inch tall tires are the way to go. Fabtech, Pro Comp, and Skyjacker have engineered 8-inch and even 10-inch suspension lifts to fit huge tires on your Super Duty. These kits include everything necessary to run big meats with the proper suspension geometry safely. Expect to perform some trimming on the front bumper, or consider replacing it altogether with a high clearance bumper to prevent rubbing. Also understand that while your Super Duty will be able to drive down any trail it fits on, you are making compromises in terms of daily driving and towing at this height. Power Stroke engines make a ton of torque and the Dana 60 and Sterling 10.5 axles under Super Duty trucks are plenty strong, but you will want to consider regearing to a lower (numerically higher) gear ratio to keep the engine in the powerband. And while you are in the diffs, why not add a locking differential for even more capability on the trail?

Is A Four-Link Conversion For Me?

The factory Ford radius arms do an excellent job of locating the front axle and resisting body roll. That said, radius arms by design inhibit articulation and cause significant changes in camber as the suspension cycles. These are not issues that reveal themselves during regular street driving. If you use your Super Duty off-road for high-speed desert driving or rock crawling, it is worth considering converting the front suspension to a four-link design. Fabtech, Icon Vehicle Dynamics, Pro Comp, and Skyjacker all offer four-link kits engineered to increase the available wheel travel on your Super Duty for improved performance off-road. Less binding also means that parts don't wear out as quickly.

Air bags are a great idea for the rear suspension of a Super Duty. They allow you to use a softer spring for a nice, cushy ride while unloaded. When hauling or towing, you just add air to the bags to handle the heavier load.

Bagging It

We have mainly focused on the front suspension since it has to deal not only with fitting big tires through the suspension travel, but also turn right and left. That doesn't mean the rear leaf spring suspension on your Super Duty should be an afterthought though. Lift blocks are the least expensive way to match the ride height of the rear suspension to the front. That extra leverage can induce axle wrap, so consider adding traction bars when running 37-inch or 40-inch tall tires and lift blocks. Another option is a replacement leaf spring pack with more arch, which will resist axle wrap better than lift blocks. The issue with leaf springs is finding a rate that is soft enough to provide a supple load when the truck is empty but still carry and tow heavy loads without sagging. Consider how you typically use your truck to help determine how stiff of a spring would work best for your specific needs. Or alternatively, air bags from companies such as Firestone and Air Lift can be combined with a soft leaf spring for the best of both worlds. Just leave them deflated when the truck is empty and add air when pulling a heavy load.

Want to run 40s without any lift? Fab Fours has what you need. Don't look at this as the cheap way out, but as an alternative that will cost as much as a quality suspension but keep the center of gravity considerably lower.

No Lift With 40s

Want to run 40-inch tires without a lift? It is possible with heavy fender trimming and a leveling kit. Rather than just chop up your factory sheet metal, Fab Fours took a page out of their Jeep playbook and applied it to Super Duty trucks to create the "Open Fender System." The kit is built from 11-gauge steel and meticulously tested for the full range of articulation and flexing with 40-inch tires. While they include a detailed 96-page instruction manual and templates for where to cut, we recommend leaving this installation to the professionals as it does take time and know how.

A Note About Tires

We have talked a lot about tire size, but tire construction and load ratings are also important considerations when lifting your Super Duty. The lightweight tires designed for a Jeep aren't going to support your fully loaded F-350. Look for tires that can support at least 3,000 lbs. each at maximum inflation values. This will allow you to run less pressure for a smooth ride and even wear during daily driving but still add air for heavy towing and hauling. Pro Comp, Toyo, and Mickey Thompson are just a few of the companies that make tires up to 40-inches tall that can support a fully laden Super Duty.

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