I Crawled Underneath The New Scout To Look At The Engineering. Here’s What I Found

As beautiful as the new Scout Traveler and Terra are, one thing that we haven’t seen nearly enough of is hardware. We’ve seen the sheetmetal and the fancy interior, we’ve heard all the specs, we’ve listened to all the heritage mumbo-jumbo marketing, but let’s all be honest: We want to see engineering. We want to see suspension. We want to see the frame. After all, we cannot truly know a car unless we know its bones, which is why I’m here to show you what I saw when I crawled under the new Scout Traveler and Terra. Let’s dive in.

OK, first things firsts: this is a body-on-frame machine, while there was unfortunately very little frame to actually see at the reveal event (there were just aero shields; more on that soon), there are a few photos from Scout’s own media KIT.

The Frame And The Range Extender

Here’s the Traveler’s frame:

And here’s the Terra’s:

Both of these appear to be steel frames; you can see that the crossmembers span above the battery, plus you can see what looks like a traditional double wishbone independent front suspension and you can see how the large hole in the rear part of the frame accommodates the rather large rear-differential-mounted electric motor (can’t wait to show you that in just a moment). You’ll also see what looks to be a cage over the range extender, a small gas engine (likely to come from the VW family) that charges the battery after the battery has depleted, which should happen after about 100 to 150 miles of EV-only range, per Scout.

Speaking of, have a look — the gasoline range extender sits at the very rear of the frame under the rear cargo area, with what appears to be…a fuel tank (?) just ahead of the battery.

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Check out that red bit shown on the right of the image below. Very interesting!

I reached out to Kevin Harty, who works at Munro and Associates to get his initial thoughts. Here are a few of them, including a note that there may need to be more crash protection for that rear range extender on the production model:

Unlike the Rivian it seems like the pack basis the rear more. I do think they might end up with more protection for the Rex with those short overhangs. Not a lot of free crush space or air gap between the E Beam.

Unlike the Rivian it seems like the pack biases the rear more.

Looking where the fuel filler neck is, I would guess that front gap in the battery area is for fuel.

Also no B pillar cab mount. Also Toyota-esque.

It’s interesting that a lot of the frames cross car structure runs over the battery versus under. Likely for service and side impact.

Also seems like a bulkhead of sorts at the front of the frame/battery area.

No delibrate [IIHS Small Overlap Rigid Barrier Crash Test] countermeasures. So maybe its all defensive in that bulkhead area.

Very interesting. There is a bulkhead just ahead of the battery. Maybe that’s for protection of that tank. I also showed Kevin the rear axle, which he refers to as the “EBeam axle.” Check it out — the motor is actually mounted directly to the rigid axle, just above. You can also see an oil cooler:

Here’s another angle (I think this is the Terra):

And here you can see the axle on the gearbox side (passenger side):

And here it is from the front. You can see there’s actually a removable pan at the front of the axle:

“The EBeam looks similar to a lot of others I have seen for customers. Weight and [road] impact to the inverter could be a concern,” he told me, mentioning that the EBeam is currently being looked at predominantly by commercial vehicle manufacturers.

To discuss this new electric solid axle — which should offer the tremendous articulation that an independent suspension setup usually cannot – I’ve sent a bunch of photos to our in-house suspension engineer, Huibert Mees. Here’s what he has to say.

A Look At The Industry’s First Electric Solid Axle (In The U.S.)

Hi, this is Huibert taking over. Just this week, as David Tracy has already reported, the Volkswagen-funded Scout brand introduced its first two models – the ‘Terra” pickup and the ‘Traveler” SUV. David is over the moon about them as are many other people, but I have some questions. Scout claims these vehicles use solid axles, which means that, as far as I am aware, they are the first EVs to do so. Normally, EVs, including all EV pickups that I’m aware of, use an independent suspension, regardless of whether the original platform used solid axles. I talked about this in my post and video about the F-150/Raptor/lighting trio.

In that case, both the base F-150 and the Raptor use solid rear axles, but the Lightning changes to a fully independent rear suspension. The reason is that with a big battery underneath the vehicle, there is no room for a driveshaft. This means the motor has to be at the rear of the vehicle, so it only makes sense to mount the motor right where the axle is and run independent halfshafts out to the wheels. Of course, the motor now takes up the space that the axle housing would need in order to move up and down with the suspension. An independent suspension design is the only practical way to resolve this problem. Or so I thought.

Up to now, solid axles and EV motors simply didn’t merge in my mind. So, what did Scout do? Well, fear not, fellow Autopians, thanks to David’s intrepid phone camera, we have some photos that offer us clues to answer this burning question. Let’s start with the front suspension:

Looks like a fairly standard double wishbone design with a Rack and Pinion steering setup. This is standard fare for pickups, even EV trucks. There’s nothing out of the ordinary, and without knowing a lot more detail about this specific design, nothing I can find fault with. A good choice! [Ed Note: I’m not a huge fan of CV-axles over u-joint axles, but independent suspension designs pretty much always use CVs, so I’ll deal with it. The downside of a CV axle is that the CV joint boots can tear while off-road, and if that happens, the joint fails. Repairing the joint on the trail is a difficult affair. On a Jeep Wrangler with a solid front axle, you have universal joints, which don’t have rubber boots to tear (just small rubber seals), and if they fail, you can replace them with a $15 part using nothing more than a socket and a rock. This, along with reduced articulation, is a small compromise from someone used to a solid front axle, but it’s entirely expected. -DT]. 

Now let’s look at the rear:

We can clearly see that this is NOT an independent suspension but is indeed a solid axle, as Scout claims. We can also see a couple of the links that hold the axle in place. Here are two slightly different angles of the same axle, with the lower one showing one of the upper control arm links:

Two lower links, a Panhard rod, and an anti-roll bar. There’s also a pair of upper links to go along with the lower links. Together, they form the necessary support and location of the axle, very similar to the Ford Bronco, Jeep Wrangler, F-150 Raptor, as well as the Toyota Tacoma and many others.

But if we look a little more closely, we see something else:

We see what certainly appears to be an electric motor located above the axle and a gearbox inline with the wheels. All of this is located in the axle housing which together with the axle shafts, brakes, wheels, and tires, makes one giant assembly. That’s a LOT of stuff that has to move up and down every time the wheels encounter a bump. It’s called unsprung mass and one of every suspension engineer’s goals in life is to reduce unsprung mass as much as possible.

Let’s Talk Unsprung Mass

Unsprung mass refers to the mass of the parts of the car that are NOT supported by the springs. This includes the wheels and tires, the brakes, the knuckles and bearings and a portion of the suspension control arms. It is “unsprung” because the springs are not supporting this mass.

When a vehicle encounters a bump in the road, the springs isolate the body and occupants from the impact via the springs. But the portion of the car, i.e. the suspension, that has to move up and over the bump, is not isolated by the springs and so all that stuff has to move out of the way. If you are going slowly, it only has to move out of the way slowly, but if you are moving at speed, the wheels/tires/brakes/knuckles/etc. have to move very quickly.

The heavier all that stuff is, the less it wants to move quickly. Conversely, once it gets moving, it wants to keep moving, and then all that mass really becomes a problem. When the suspension moves up over a bump, the things that stop it and push it back to its original place are the springs and dampers. If the unsprung mass is low, the springs and dampers don’t have to work very hard to stop the suspension movement and push it back down. With high unsprung mass, the springs and dampers have to work much harder and may not be able to stop all this movement in time. The tires could, in extreme cases, momentarily lose contact with the ground.

If you’ve ever driven an old solid axle car around a bumpy turn, you will probably have experienced the sideways dance these cars would do as the tires lose contact with the ground and lose grip. Not very pleasant. Of course, we could use really stiff springs and dampers to help control the axle motion but that would hurt ride, and we don’t want that.

This whole phenomenon is the main reason solid axles are no longer used in passenger cars and independent rear suspensions have taken over. It is just not possible to get the level of ride, comfort, and handling with the unsprung mass of a solid axle these days.

So, what can we make of this design used by Scout? To be honest, I have my doubts. EV motors are not particularly small, and that gearbox most likely contains a set of strong steel gears and a differential. None of this is light especially compared with just a differential as you would find in any other solid axle design. It will probably be fine when rock crawling, but I can see problems with ride and shake in the vehicle as all that mass is asked to move over a bumpy road at anything more than 20-30 MPH. I hope I’m wrong, but my experience tells me this could be a big issue for Scout.

There is one more thing I will mention here although it is not suspension related and is really outside my area of expertise. That electric motor needs power and the cables that provide that power are big. They also carry a LOT of current. With the motor moving up and down, these cables have to move up and down as well, and I would worry about their durability. I can only assume Scout has this figured out and provided adequate strain relief on both ends of each wire. You do NOT want one of these cables fatiguing and causing a short circuit. This is all very new information and very incomplete, I know. We will of course bring you more details as we learn them.

Off-Road Hardware And Some More Underbody Images

OK, back to David again.

Peeking at the Traveler’s off-road attributes (since it’s clearly the more capable of the two vehicles), the front overhang is absurdly small. I’d guess an approach angle of over 40 degrees, thanks in part to those big 35-inch all-terrain tires:

The arse is a bit larger, but the departure angle looks to be at least 33 degrees, which is good:

My biggest concern from a geometry standpoint is the Traveler’s belly. Those rockers look fairly low, though it’s not too bad. I’m also moderately concerned about that rear tire carrier only being just outside of the vehicle’s departure angle. You don’t want to bash that on a slope as you come off it:

But overall geometry looks great. The tow points up front were basically just for looks; the production model should have a similar appearance, but not feel so plastic-y (this was a concept vehicle). The tow point locations up front look great — right up front, one on each side. I could do without the climbing rope hole (that’s not really appropriate for towing), but it’s fine:

Tow points out back are also right on the bumper, one on each side; I’m a fan:

As for skid plating, a lot of what I saw under the vehicle looked like plastic aero covers. I could be wrong, of course, and it’s possible this isn’t production intent:

But up front there is what looks like an aluminum bash plate:

And there’s also one at the rear:

So that’s just a quick look at the new Scouts’ tech. There’s a good look at that EBeam axle, there’s a close look at the underbody shielding, there’s a discussion of the range extender and frame, and there’s some great insight from in-house suspension guru Huibert Mees. I can’t wait to learn more about these machines — especially the battery chemistry/geometry/cooling — as they get closer to production so we can get really nerdy.