Connect with us


2021 Ford F-150 Suspension Deep Dive

I don’t need to tell you that any all-new redesign of the Ford F-150 is a big deal. But last time around the talk was centered on its then-new aluminum body, and this time all the attention is being paid to the new hybrid powertrain, the folding shifter and the big touchscreen. That stuff is all well and good, but what about the suspension that makes this truck work?

Fear not, friends. We’re about to take a good look at the underpinnings of the brand-new 2021 Ford F-150. And it’s a very representative one, too. This truck is the volume-selling XLT model with a crew cab. It has four-wheel drive, a 2.7-liter EcoBoost V6 engine, and its suspension has the standard GVWR — which is 6,600 pounds in this cab configuration. It’s fitted with the XLT Sport Appearance package, which normally swaps out the standard 17-inch wheels for an 18-inch setup, but this truck has been further “upgraded” to 20-inch wheels and tires, which is the kind of thing I tend to scoff at on a 4×4. Yes, you can lump me in with the “save the sidewalls” crowd.

Even though there are no marquee changes to the suspension of the 2021 Ford F-150, there are some interesting and thoughtful tweaks worth examining. Though we touched on them a bit in our F-150 review, this is called a Suspension Deep Dive for a reason. Let’s take off the wheels, break out the colorful arrows and see what Ford’s engineers managed to change without much fanfare.


At first glance, the front end looks similar to the last generation. But eagle-eyed Ford fans might be able to spot a difference even here.


As before, it’s a double wishbone setup with an aluminum knuckle (yellow arrow) and steel upper and lower control arms (green).


The knuckle has been redesigned and weight-optimized. But that’s not the only thing that’s different about it. I’m going to keep you guessing until the last possible minute.

I’ve received conflicting information on the new F-150’s track width. One Ford source said it was an inch wider. An online source said it was three-quarters of an inch wider, but I got something different when I compared the 2020 and 2021 F-150 track width specs on the Technical Specifications Sheet: the 2021 has 0.3 inches more track width across the front and 0.7 inches at the back. I tend to rely most on specs I can see printed on charts, so that’s what I’m going with. Basically, the new F-150 has a bit more track width.


The upper control arm employs the same sort of mid-mount placement the last generation F-150 used. By that I mean it’s not the high-mount type that puts the ball joint (yellow) above the tire, but it’s also not the low in-wheel mount that places a lot of stress on the upper arm and its ball joint and inner pivots.


The lower control arm is a nice-looking steel weldment made of two main pieces that look to be hydroformed. The coil-over shock mounts much the same as it did before, and the attachment point (yellow) looks to be about 70% of the way out from the inner pivots, so the motion ratio for the spring and the damper is close to 0.70.

It’s also worth pointing out that there are no eccentrics (green) for alignment adjustment at the inner pivots. When I asked Ford about this, they said their frame assembly is so accurate they don’t need them. I’m pretty sure other truckmakers could make a similar statement, but what about what may happen in the course of ownership? This seems odd on a vehicle that’s going to get used, abused and modified by so many buyers. This isn’t new, though. The outgoing truck was set up this way, too.


Those nubs are steering stops. They’re the same sort as last year, but they look more prominent. Further back, they’ve done away with the stiffening bar (black) that used to run between the two legs of the arm (ha!).


At full lock, those nubs (yellow) are meant to engage the prongs and the reinforced area below them that are cast into the knuckle. Having the steering contact here when full lock is reached is a lot better than having the steering rack itself reach its internal limit. The weird part here is that Ford saw fit to put two stops on each lower control arm. Typically only one is needed, because the one on the other side of the truck does the job when you turn the opposite way.


This is the change that some of you may have already noticed. The stabilizer bar linkage (yellow) connects directly to the knuckle. Last time around this link went down to attach to the lower control arm itself at a spot midway along its rear leg. This new link mounting location has several benefits. First, the motion ratio is a cool 100% instead of 40 or 50%. This extra efficiency means a smaller and lighter stabilizer bar (green) can do the same job of the last truck’s bigger and heavier one.

But there’s more to it than that, according to Ford. The old setup loaded the lower arm asymmetrically, and that introduced an uneven load that made it harder to tune and optimize the bushing compliance. This new load path brings stabilizer bar forces into the lower wishbone via the knuckle’s lower ball joint, and that makes it easier to keep everything square. This change may well be why they were able to remove the stiffening bar between the two legs of the lower arm, which is another source of suspension weight loss if that’s the ultimate reason or not.


This seems to be another potentially significant but unsung change to the 2021 Ford F-150. The F-150’s four-wheel-drive system has typically used a vacuum-operated hub disconnect system called IWEs (Integrated Wheel Ends) that allow the wheels to freewheel when the truck is in two-wheel drive. But these hub disconnect units (yellow) look different, and they go by the slightly different acronym EIWE, which stands for electric integrated wheel end.

Now, I’m pretty sure I’m still seeing one vacuum line along with a control wire. I’ve not seen a cutaway that shows the innards, but it looks like the electronics that control the vacuum have been moved to the hub area itself. What I do know is that if you search Ford IWE you’ll see loads of articles and videos on how to fix previous IWEs when they fail. Do they fail often? I don’t have the statistics. Is this a step forward? It’s probably too early to tell. But it does seem to be a departure worth pointing out.


The front brakes are made up of sizable dual-piston sliding calipers and hefty ventilated rotors. I like how the caliper has strategically-placed cutouts (yellow) that give you visual access if you want to eyeball the state of both the inner and the outer brake pads.


This chaotic scene hides a new electronic master cylinder. There’s no vacuum booster buried here because the new 2021 Ford F-150 is more or less brake-by-wire. Now, there is a hydraulic circuit in such layouts that is used to both gauge the driver’s intentions and maintain a mechanical fail-safe backup. But the primary brake-force distribution to each wheel is controlled here and sent to each wheel through four distinct brake lines fed from an oversized ABS pump.

This isn’t the first time Ford has done this. The Ford Explorer underwent this transition a year ago. The reason is the same in both cases: both the Explorer and F-150 have a new hybrid variant. Hybrids use magnetic regenerative braking some of the time, traditional friction braking other times, but usually it’s a blended combination of both. They need a brake system like this in which a computer constantly analyses the severity and urgency of the driver’s input along with the state of the battery to decide which type of braking to deploy, and how much.

But at the Explorer launch I was impressed even more by the non-hybrid’s brake pedal feel, and sought out an engineer to get the story. He said that both shared the same new master cylinder system, and that it was even easier to tune brake response and feel on the non-hybrid models where regenerative braking and the blended mode aren’t present. All I knew is the Explorer’s brakes felt intuitive and consistent, and this new F-150’s brake pedal does, too.


The rear end of the F-150 is both traditional and revolutionary at the same time. It rides on leaf springs, but …


These are no ordinary leaf springs. Right away, you notice that there’s just one main leaf (yellow) and a subtly odd-looking secondary (green) aka helper spring.


But there’s more to it than that. The main leaf tapers along its length — it’s thicker under the u-bolts (yellow) and gets thinner as you get closer to the mounting eyes (green) at either end. For its part, the helper (red) looks odd because it is made of a composite material, not steel.

All of this saves weight. The main single leaf is 11 pounds lighter that a normal multi-leaf pack would have been. The composite helper is 7.5 pounds lighter than its steel counterpart would be. That’s a savings of 18.5 per side, and a good deal of that is unsprung.

There’s more to it, though. Fewer leaves means less friction, less noise, and smoother engagement. Indeed, there’s less kick when this truck rolls through certain drainage ditches at intersections near my house.

This truck uses this weight savings (and others around the vehicle) to up its payload. The same 6,600-pound GVWR that let a similar 2020 truck haul 1,690 pounds of payload will accommodate 1,760 pounds of payload here. Clearly, the spring design isn’t holding back this truck.

However, all that changes if you order the max towing or increased payload options. Those variants revert to a multi-leaf pack with a steel helper. And there are other combinations that use all-steel multi-leaf packs. Point is, this is an excellent setup for the kinds of typically equipped personal use pickups many of us tend to favor.


This particular truck isn’t lifted. But it needs this spacer block (yellow) because the single-leaf pack isn’t very thick, and because less curve is necessary in this particular leaf to get the needed performance. They need a certain block thickness to get the truck to its design height.


The F-150’s shock absorbers sit outboard of the springs, which improves the motion ratio of the damper. The closer the damper is to the tire, the more efficient its damping response will be. This only applies to single-wheel impacts and body roll, though. Equal simultaneous impacts (such as going through a dip) aren’t affected by how far out the shocks are mounted.


You may have caught glimpses of the urethane bump stop (yellow), which has an arched shape that’s built to register on the axle tube directly.


As it has before, the F-150 uses inverted “tension” shackles (yellow), so named because any load pressing down from the bed or wheel impact crashing up from the bottom will pull the shackle in tension, with over-slung springs and the frame-side shackle mount below.


With the springs outboard of the rear frame rails and the shocks outboard of the springs, the left-side upper shock mount (yellow) is dramatically cantilevered off to the side. It’s a sturdy piece, with generous welds and a strategically-placed crossmember, but it’s hard to imagine Raptor-sized shock loads coming in through this part. As much as anything, this tells me the rumors of a coil-sprung rear end on the 2021 Raptor are likely to be true.


The right-rear shock (yellow) points forward, not aft, because the 2021 F-150 has staggered shocks like most modern leaf-sprung trucks. The other thing to notice here is how close the shock is to the tire and wheel, something the other shot didn’t quite drive home. It’s also easy to see how having the shock outboard like this is a big help when picking your way through a rocky trail off-road.


The rear brakes are made up of a ventilated rotor and a single-piston sliding caliper (yellow) with an electronic parking brake actuator (green) bolted onto the back. It’s obvious that they’ve thoughtfully weight-optimized these pieces, quite possibly to offset the added weight of the electronic parking brake actuator itself.


The 20-inch wheels I groused about at the outset are not light. Each assembly weighed 81 pounds on my scale. But there’s something to like here, too. This year’s 20-inch tire size is 275/60R20, which is bigger than the 275/55R20 optional size this truck would have had in 2020. What that means is this 2021 XLT’s tricky wheels are 33 inches in diameter, compared to 32 inches last year. So, yeah, they’ve got more sidewall. And you can feel it, too. This truck’s ride is a bit smoother and less harsh than it might otherwise have been.

But is it the extra sidewall? The reconfigured stabilizer bar? The lighter single tapered-leaf springs? That’s just it. The 2021 F-150 isn’t radically different in concept from the 2020 truck it replaces, but there are a raft of small changes that add up to a noticeable uptick in refinement. I still say coil springs are in every 150/1500-series truck’s future, but Ford has kicked the can down the road a bit farther.

Related Video:

Source link