Engineering Experts Show How Tesla Saved Money On The Cybertruck’s Suspension

The Tesla Cybertruck is unlike most any pickup on the market. That’s obvious just by looking at it, given its shape and its stainless steel construction. However, the differences are more than skin deep, as a teardown by engineering firm Munro & Associates readily reveals.

We’ve had experts talk us through some details of the Cybertruck’s suspension before. However, we’re now getting a deeper assessment, thanks to the team from Munro, who have pulled the truck apart and laid the pieces out on a table.

Kevin Harty, Sr. Design Consultant at Munro & Associates, walks us through the suspension design step by step in the company’s latest teardown video. Front and rear, we get some professional insight into why the Cybertruck is built the way it is.

Up Front

The front upper control arms have been a particularly controversial part of the Cybertruck’s design. Lots of folks have commented on the stamped-steel design, which looks relatively lightweight for a heavy off-road vehicle.

However, Harty notes that it’s quite smart from a manufacturing perspective. Typically, upper control arms are manufactured with two steel parts welded together in a “clamshell” design for strength. This comes with approximately double the tooling costs to produce the two individual parts, and it costs money to weld them together, too. The Cybertruck design uses just a single stamped part, significantly reducing the cost of production. The stamped part still requires the bushing mounts to be welded in, but it’s a lot simpler compared to many contemporary designs, he says.

The front knuckle is quite something to behold, given its immense size. “The gooseneck portion of this is arguably one of the tallest that I have seen,” says Harty. It features a deep curve inward to clear the Cybertruck’s large tires, with the upper balljoint mounted directly above the tire tread. Some other brands put the balljoint inboard of the tire, which allows fitment of very large tires. It’s not possible to do this easily on the Cybertruck, as larger tires will foul on the balljoint mounting bolt.

Harty questions whether this packaging choice may be for a reason, given some concerns around the strength of the Cybertruck’s upper control arms. “I wonder, if essentially… is this kind of an enabler to keep the tire size on a Cybertruck relatively reasonable, and therefore the loads brought into the vehicle reasonable and controllable as well.”

.@YammerTime01 @BradMunchen @VickiBryanBondA @Tazerface16 @Karthik48966191

This is a toy suspension–a living joke. Off road in Arizona, New Mexico, Wyoming: mountains, desert, prairie, on any rough, rocky, pothole strewn 4WD road and the casting is cracked and arms are bent. pic.twitter.com/Mf4ArwhhhH

— Very Long Range (VLR) ???????? ???????? ???????? (@ned_christie) November 25, 2023

The Cybertruck’s upper front balljoint design does limit tire size, somewhat. However, our own Huibert Mees doesn’t reckon there’s necessarily a strength issue here. Here’s what Huibert had to say about the upper ball joint being above the tire:

I can assure everyone that this type of suspension design is extremely common and has been on production since the late ’70s when it was first introduced by Mercedes in the W123.

Mercedes uses it. BMW uses it. Ford, GM, VW, Jeep — they all use it. In fact, I can’t think of a single car and truck manufacturer that doesn’t have some form of an SLA in production. Even Tesla uses it on the Model S.

I think what is throwing people off is the fact that the upper arm is so visible in the Cybertruck. Most cars have a much smaller fender-to-tire gap, so the upper arm is only visible if you get up close. With the Cybertruck’s large fender opening, the suspension is very visible, and a shiny aluminum part really stands out.

What this design DOES do, however, is eliminate your ability to install larger tires. A larger tire would interfere with the stud of the ball joint so it just wouldn’t fit. Most trucks that use SLA’s (like the F-150, for example) solve this problem by placing the upper ball joint next to the tire. This keeps it out of the way of a larger diameter tire. It also makes the upper arm and ball joint more difficult to see which is why many people don’t realize these trucks have such a suspension design. You can see that here on my 2020 F150.

David Tracy notes that the Jeep Grand Cherokee also has such a suspension design (see above).

In any case, the design of the Cybertruck’s suspension means that the upper control arm doesn’t see huge loads, anyway. “For this style of suspension setup, not that you don’t see any loads with the upper control arm, but it’s essentially controlling camber,” Harty explains. “[It’s] keeping the wheel from cambering out or cambering in, and it’s controlling the arc of the suspension as it travels through its entire motion.”

Instead, most of the loads are carried by the lower control arm and passed directly into the shock. In comparison to the thin stamped steel of the upper control arm, the lower part is a chunky cast unit. It features a concentric bushing up front, and a perpendicular bushing at the rear. “This is typically for comfort and helping with NVH and locating the wheel itself,” says Harty.

The design of the lower control arm is somewhat more complicated than the upper. That’s down to the need to package it around the wheel envelope, the shock mount, and other components. Harty also notes that aluminum casting is a great choice for making these parts, for strength, weight, and packaging reasons. It allows the creation of complex geometry for tough packaging situations, with minimal wastage. “They’re very efficient as far as how much of the material it takes to make the part ends up being in the part,” he explains. The front lower control arm is the only one made in aluminum, with the rest of the control arms relying on steel, front and rear.

At this time, the jury is still out on the purpose of the little metal nubbin mounted to the upright. When we last looked at this curious part, it appeared to be either a mud scraper or a device used to bust the rim in a crash. Harty also raises the possibility that it could be a tuned mass. However, his leading theory is that it’s used to help the truck pass the Small Overlap Rigid Barrier (SORB) crash test. The nubbin may help destroy the rim or ensure it’s pushed outward during a crash, which helps avoid the wheel and tire assembly impacting or intruding into the cabin. “The proximity for that nugget in relation to the wheel envelope is definitely pushing our opinion… to small overlap and helping with crash [safety],” he says.

As for the hubs, the Cybertruck has a fairly conventional setup for a modern vehicle. Harty notes the six-lug hubs use “generation 3” style wheel bearings. These are integrated units that combine the hub and bearing into a single replaceable unit, easing maintenance. Otherwise known as “unit wheel bearings,” they also feature the ABS sensor ring as an integral part of the assembly. Harty notes that Hyundai has pushed wheel hub technology further, also integrating the drive axle CV joint into the hub itself on the Ioniq 5. He explains that Munro has been looking for similar parts on vehicles from other automakers, but is yet to find them anywhere else just yet.

Moving Rearwards

The rear suspension is not entirely dissimilar from the front, at least in its general layout. Rear lower and upper control arms are both made out of stamped steel. The lower uses a clamshell-style design, As for the rear upper control arm, it’s reminiscent to the front part, but it has some reinforcements welded in to add rigidity. Harty also notes the upper control arms are mounted directly to the body. During Cybertruck assembly, the rear drive cradle is then jacked up and installed from underneath, with the upper control arms already in place.

Some of the rear end parts were still in the scanning process at the time of shooting, so we don’t get a good look at them here. Regardless, there’s still plenty to learn. Notably, the rear subframe itself is actually made in China, something Harty notes was also apparent on the Model S Plaid. In contrast, the stamped parts are all marked as being manufactured in the US. “Managing that balance of how many parts are made within the US, [and] how many parts are made outside the United States is important,” says Harty, noting the impact of legislation like the United States–Mexico–Canada Agreement (USMCA).

“When you look at the air [dampers] here for the Cybertruck… you can see, as far as material selection, [there is] lots of use of steel throughout,” says Herty. He also highlights the use of EPDM rubber parts that help keep dirt and other contaminants away from the air bladder assemblies. As for the air pump and reservoir, he notes that packaging them above the rear gigacasting leaves them very well protected.  As for the pump itself, it’s mounted with very flexible rubber to minimize noise or vibrations transferred to the cabin. Herty explains that the Munro team was disappointed with the air reservoir itself though, noting it’s a standalone part that hasn’t been integrated with anything else to save costs.

“Personally, I’m not a huge fan of air ride, just from the complexity standpoint,” says Herty. “But air ride is a relatively cost-effective way to get, essentially, a lot of comfort in a vehicle.” While electromagnetic dampers can offer great performance and comfort as well, they come at a higher price. Herty puts this down to their requirement for clean room assembly, amongst other things. He notes that the Ram 1500 has used air ride to similar effect for several years now. It also makes it easy to change the vehicle’s ride height on a whim. “I think the air ride offers a nice balance between the cost of the system and performance for what you’re doing on trucks,” says Herty. “That’s typically why you see it in these segments, and not necessarily in more weight or performance-oriented segments like cars.”

Harty contrasts the Cybertruck’s relatively simple air suspension system with the more complex route seen on Rivian’s vehicles. “Not only is the [Rivian] system twice as complex because it’s an air-over-hydraulic system, but all the materials throughout are more costly,” he says. However, he notes that Rivian’s design has some advantages. It has no need for swaybars, for one. Plus, it’s more tunable for different drive modes and ride heights, and each corner of the suspension is totally isolated.

Overall, it’s clear that cost has been a big driver of engineering decisions on the Cybertruck platform. “I think maybe some of those choices that we’re seeing here for both materials and even suspension system are to help offset the cost that we’re seeing elsewhere in the vehicle,” says Herty. He also notes that getting the truck to market in a reasonable time likely played a major role, too.

So often, what we learn about cars and trucks is limited to what we can see on the outside. We read reviews and maybe take a glance under the hood or under the body to get a better idea of how a vehicle performs and how it was built. But it’s hard to beat the real detailed look that you can get when you pull vehicle apart down to the individual component level.

Image credits: Munro Live via YouTube screenshot