Posted by Jason Locke on 9/20/2019 to
Before you Buy
It's a well-known fact that the 2015-2019 F150s are more than a bit wallowy in the rear with the factory suspension setup. The rear ends of these trucks tend to bounce and jounce around like mad after going over even the slightest bumps and the rear-end roll makes high-speed corners and highway turns "interesting" to say the least. The good news is that there's more than a few suspension upgrades that can seriously help your F150 out and most won't even break your bank. However, there's more than a few rear suspension parts and upgrades to choose from and not all of them will play nice with each other. That's why we put together this handy guide so that you can find the right combination of rear shocks, rear blocks, add-a-leafs, leaf springs, helper springs, sway bars, or other rear suspension upgrades for your very own 2015-2019 F150.
Rear Shocks:
By far the biggest culprits causing an unsavory rear ride and handling issues are the stock rear shocks. The factory shocks are pretty basic hydraulic shocks and neither their valving or gas charge does enough to keep your F150's rear from bouncing around or rolling from side-to-side. The good news is that even the most basic aftermarket rear shocks can help your F150 feel and handle like an entirely new truck. Performance rear shocks are the best, bar none, bang-for-you-buck suspension upgrade you can make for your truck. With their revised internal designs and vastly improved valving, F150 rear shocks can keep your truck's rear end under far better control than stock. While rear shocks alone don't add any rear ride height to your F150, many can handle slightly higher ride heights than stock, allowing you to use larger rear blocks, add-a-leafs, or even entirely new leaf packs with impunity. If you have a fairly general-purpose truck that is mostly driven on the street, then take a look at the Bilstein 5100s or Eibach Pro-Truck Sport shocks. If you're doing the occasional trail ride and truck sees a decent amount of off-roading, take a look at the Halo Lifts Boss 2.0s, Fox 2.0s, Bilstein 5160, or ICON 2.0 Aluminum Series Rear Shocks. If you're getting really aggressive your truck and you need maximum off-road performance and on-road handling, check out the Fox 2.5, ICON 2.5, King 2.5, or Elka 2.5 rear shocks.
Rear Blocks:
While most folks are itching to get rid of their factory rake with a leveling kit, there's plenty of reasons why you may want to add some rear ride height to your truck, and an aftermarket rear block is a painless and inexpensive way to make it happen. Aftermarket rear blocks install between your F150's leaf springs and axles and generally come with new U-bolts to replace the shorter stock U-bolts. On 4WD F150s, these rear blocks will replace the stock 1.25" or 1.50" rear block (block size varies by submodel and packages) to get you a net amount of rear lift, which is the difference in size between the new block and the stock block. On RWD F150s without stock blocks, aftermarket rear blocks add a gross lift, which is the actual size of the rear block in question. Rear blocks are a great way to add back a smidge of rake after adding a leveling kit, especially if you're going to be towing and hauling on the regular so that rear squat is somewhat mitigated. While rear blocks are a nice, easy upgrade, there are a couple of downsides. The first is that you'll need to be careful with your shock selection, especially if you're looking at a 3" rear block or larger. Many aftermarket shocks are only rated for 1" of additional rear lift, and 3" blocks add 1.75" or 1.50" of net lift on 4WD trucks. In the case of a 3" rear block, you'd need a shock that's capable of handling at least 1.50" of lift, if not more. Larger rear blocks also increase the possibility of axle wrap, but that's generally only an issue on extremely powerful truck putting down a ton of torque.
Add-a-Leaf Kits:
Like rear blocks, Add-a-Leafs add some rear ride height to your F150. Unlike rear blocks, however, add-a-leaf kits add some extra cargo-carrying capability and will keep your F150's rear end from sagging as much as the stock leaf pack alone with the same given load. Add-a-leafs are a great upgrade for F150's that see a lot of heavy towing, and will help prevent sag when you're towing and hauling close to your F150's payload capacity, GVWR, or GCWR. Speaking of factory tow ratings, while an add-a-leaf kit can help with handling extra capacity, they still don't allow you you to surpass your F150's rated payload, GVWR, or GCWR. So if you're eyeing a toy hauler or trailer that's just a smidge over your truck's GVWR, an add-a-leaf kit will not help you. In fact, nothing on this list will allow your truck to violate any of its factory-rated capacities. Another potential issue with add-a-leafs is that they do stiffen up ride quality to some degree, though aftermarket shocks can help to some degree. Like with rear blocks, you'll need to be careful with your shock selection, since not all shocks can handle a 1.5" to 2" ride height increase.
Leaf Springs:
While rear blocks and add-a-leafs do add some ride height and can help with towing, neither upgrade will add any rear travel. Rear shocks can add a smidge of travel, but they're limited pretty quickly by the stock leaf springs. If you want to squeeze some travel out of rear suspension, you'll need new leaf springs. These leaf springs feature more leafs made with thinner-gauge steel that improves flex and downtravel over the stock leaf packs. These springs come in a couple of different varieties, with some being tailored to add ridge height and/or support some extra constant-load in the bed. These leaf springs replace the stock leaf packs and delete your stock block. Now, most of these leaf springs are designed for the 2017-2019 Raptors, but they will also fit the 2015-2019 F150s, though you will get about 1/2" more ride height than what they're rated for on the Raptors. While these leaf springs do improve real travel, they can actually hurt you when it comes to towing and hauling, which is definitely something to keep in mind. Another issue is that you'll need the right shocks for one of these leaf packs. A lot of shocks can't handle the extra travel of these springs, and you're likely going to have to use 2.5 shocks with piggyback reservoirs with a set of leaf springs.
Helper Springs:
Helper Springs are essentially designed for towing applications, and there's two basic types. Extended Bump Stops like those from SuperSprings and Timbren replace your stock bump stops with extended versions that do a better job of absorbing axle force, but also support your F150's rear axle when it starts to sag. Wrap-Around Springs like Hellwig's EZ990 and SuperSprings Self-Adjusting Springs provide extra support for your F150's factory leaf packs, which helps them resist sag under load. Both types of helper springs do essentially the same job, through wrap-around springs are a lot easier to install and remove. However, Extended Bump Stops can also help your loaded ride and provide energy absorption for your axle if you take your truck off-road.
Rear Sway Bars:
Another set of towing-oriented upgrades are Rear Sway Bars. Rear Sway Bars provide extra rear-end stability and help prevent side-to-side swaying motions when both loaded and unloaded. These sway bars comes with their own end links that allow them to easily bolt on to your F150. Sway bars are a nice upgrade for pretty much any truck that tows and hauls on the regular. The only real issue you can run into with sway bars is compatibility with other components, larger aftermarket differential covers, helper springs, larger rear blocks, add-a-leaf kits, and lift kits can all make sway bars an untenable option.
You can't really go wrong with any rear suspension upgrade, though there are a lot of things you'll need to think about before taking a dive. One thing we didn't really talk about were rear shackles. Shackles are...fine, though we're not huge fans of them. Lowering shackles take away ride height, but add travel. Lifting shackles add height, but can hurt travel depending on their design. They can also play hell when trying to mix and match other suspension components, especially in regards to figuring out what ride height you'll be at after it's all said and done. They're also a lot tougher to install than a lot of other more simple options. However, they are an option if you want to go that route.
By far the biggest culprits causing an unsavory rear ride and handling issues are the stock rear shocks. The factory shocks are pretty basic hydraulic shocks and neither their valving or gas charge does enough to keep your F150's rear from bouncing around or rolling from side-to-side. The good news is that even the most basic aftermarket rear shocks can help your F150 feel and handle like an entirely new truck. Performance rear shocks are the best, bar none, bang-for-you-buck suspension upgrade you can make for your truck. With their revised internal designs and vastly improved valving, F150 rear shocks can keep your truck's rear end under far better control than stock. While rear shocks alone don't add any rear ride height to your F150, many can handle slightly higher ride heights than stock, allowing you to use larger rear blocks, add-a-leafs, or even entirely new leaf packs with impunity. If you have a fairly general-purpose truck that is mostly driven on the street, then take a look at the Bilstein 5100s or Eibach Pro-Truck Sport shocks. If you're doing the occasional trail ride and truck sees a decent amount of off-roading, take a look at the Halo Lifts Boss 2.0s, Fox 2.0s, Bilstein 5160, or ICON 2.0 Aluminum Series Rear Shocks. If you're getting really aggressive your truck and you need maximum off-road performance and on-road handling, check out the Fox 2.5, ICON 2.5, King 2.5, or Elka 2.5 rear shocks.
While most folks are itching to get rid of their factory rake with a leveling kit, there's plenty of reasons why you may want to add some rear ride height to your truck, and an aftermarket rear block is a painless and inexpensive way to make it happen. Aftermarket rear blocks install between your F150's leaf springs and axles and generally come with new U-bolts to replace the shorter stock U-bolts. On 4WD F150s, these rear blocks will replace the stock 1.25" or 1.50" rear block (block size varies by submodel and packages) to get you a net amount of rear lift, which is the difference in size between the new block and the stock block. On RWD F150s without stock blocks, aftermarket rear blocks add a gross lift, which is the actual size of the rear block in question. Rear blocks are a great way to add back a smidge of rake after adding a leveling kit, especially if you're going to be towing and hauling on the regular so that rear squat is somewhat mitigated. While rear blocks are a nice, easy upgrade, there are a couple of downsides. The first is that you'll need to be careful with your shock selection, especially if you're looking at a 3" rear block or larger. Many aftermarket shocks are only rated for 1" of additional rear lift, and 3" blocks add 1.75" or 1.50" of net lift on 4WD trucks. In the case of a 3" rear block, you'd need a shock that's capable of handling at least 1.50" of lift, if not more. Larger rear blocks also increase the possibility of axle wrap, but that's generally only an issue on extremely powerful truck putting down a ton of torque.
Like rear blocks, Add-a-Leafs add some rear ride height to your F150. Unlike rear blocks, however, add-a-leaf kits add some extra cargo-carrying capability and will keep your F150's rear end from sagging as much as the stock leaf pack alone with the same given load. Add-a-leafs are a great upgrade for F150's that see a lot of heavy towing, and will help prevent sag when you're towing and hauling close to your F150's payload capacity, GVWR, or GCWR. Speaking of factory tow ratings, while an add-a-leaf kit can help with handling extra capacity, they still don't allow you you to surpass your F150's rated payload, GVWR, or GCWR. So if you're eyeing a toy hauler or trailer that's just a smidge over your truck's GVWR, an add-a-leaf kit will not help you. In fact, nothing on this list will allow your truck to violate any of its factory-rated capacities. Another potential issue with add-a-leafs is that they do stiffen up ride quality to some degree, though aftermarket shocks can help to some degree. Like with rear blocks, you'll need to be careful with your shock selection, since not all shocks can handle a 1.5" to 2" ride height increase.
While rear blocks and add-a-leafs do add some ride height and can help with towing, neither upgrade will add any rear travel. Rear shocks can add a smidge of travel, but they're limited pretty quickly by the stock leaf springs. If you want to squeeze some travel out of rear suspension, you'll need new leaf springs. These leaf springs feature more leafs made with thinner-gauge steel that improves flex and downtravel over the stock leaf packs. These springs come in a couple of different varieties, with some being tailored to add ridge height and/or support some extra constant-load in the bed. These leaf springs replace the stock leaf packs and delete your stock block. Now, most of these leaf springs are designed for the 2017-2019 Raptors, but they will also fit the 2015-2019 F150s, though you will get about 1/2" more ride height than what they're rated for on the Raptors. While these leaf springs do improve real travel, they can actually hurt you when it comes to towing and hauling, which is definitely something to keep in mind. Another issue is that you'll need the right shocks for one of these leaf packs. A lot of shocks can't handle the extra travel of these springs, and you're likely going to have to use 2.5 shocks with piggyback reservoirs with a set of leaf springs.
Helper Springs are essentially designed for towing applications, and there's two basic types. Extended Bump Stops like those from SuperSprings and Timbren replace your stock bump stops with extended versions that do a better job of absorbing axle force, but also support your F150's rear axle when it starts to sag. Wrap-Around Springs like Hellwig's EZ990 and SuperSprings Self-Adjusting Springs provide extra support for your F150's factory leaf packs, which helps them resist sag under load. Both types of helper springs do essentially the same job, through wrap-around springs are a lot easier to install and remove. However, Extended Bump Stops can also help your loaded ride and provide energy absorption for your axle if you take your truck off-road.
Another set of towing-oriented upgrades are Rear Sway Bars. Rear Sway Bars provide extra rear-end stability and help prevent side-to-side swaying motions when both loaded and unloaded. These sway bars comes with their own end links that allow them to easily bolt on to your F150. Sway bars are a nice upgrade for pretty much any truck that tows and hauls on the regular. The only real issue you can run into with sway bars is compatibility with other components, larger aftermarket differential covers, helper springs, larger rear blocks, add-a-leaf kits, and lift kits can all make sway bars an untenable option.