Is This The Second Coming of the Body-On-Frame SUV Craze?

There is always a Wrangler “fighter” on the horizon and the latest is the revival of the GMC Jimmy. It’s getting wild, but now it’s time to come back to Earth.

The idea of a Wrangler fighter isn’t anything new. Since its introduction during the TJ era and increased popularity since, an equal mid-sized body-on-frame SUV has been on the radar of Ford and GM. Neither brand has really had anything close to it since the original CJ, Bronco, and K-series Blazer. You could say that Ford had something close with both the Bronco II and the Explorer, but we’d argue that they weren’t equal. They were more closely related to the Cherokee and that would be the same for the Chevrolet S10 Blazer/GMC S15 Jimmy.

 Why the Excitement for the Jimmy?

IMAGE: 2020 GMC Acadia AT4 by GMC

As of this writing, Car and Driver have speculated that a new GMC Jimmy would be launching as a 2022 model with the underpinnings of an updated version of the Chevy Colorado/GMC Canyon – the upcoming VSS-T platform that replaces both the GMT 31XX mid-size and T1XX full-size Truck/SUV platforms. Again, this isn’t new speculation but it hasn’t been confirmed. If true, it would be hot on the heels of the upcoming Ford Bronco revitalization and “Baby Bronco/Scout.” It would also buck the trend of the crossover SUV which is already happening at Ford with the 2020 Explorer and the 2020 Lincoln Aviator. It would be the first time GM would have a real Wrangler fighter.

Jimmy of a History Lesson

The Jimmy also has a history with GM for enthusiasts. The original Jimmy was based off the K5 full-size much like its Blazer cousin, but it got the name in a comparable way that Jeep’s was created – GM could be phonetically sounded as “Jimmy.” It was also a truck with a full removable top to start but it changed to a half-cab in 1976.

In 1982, the Jimmy name returned when the S10/S15 pickup was introduced in 1982 on the GMT330 platform. The pickups were designed to replace the Chevrolet LUV. While no longer a full-size SUV and lacking the removable hard top that made the nameplate famous, the Jimmy – and the Blazer – proved to be popular vehicles. It began life as a two-door SUV but gained an extra set of doors by its 1991MY (Model Year).

Death of Body-On-Frame

This first generation would stick around until 1994 when its more rounded second generation would debut as a 1995MY vehicle and would be sold until 2005. It was still on the GMT330 platform, but the body had completely changed. There was a hint at its direction and name change in 1998 with the Envoy.

It was essentially an Oldsmobile Bravada with a GMC badge and grille. This made it a more upscale vehicle and was the direction that GMC would continue to go with all their vehicles, especially after the demise of Oldsmobile in 2004.

The GMC Envoy and GMT360/370/305 platform would debut in 2002 and end in 2008. This would also be the last mid-sized, body-on-frame SUV GM produced. In 2006, the GMC Acadia on the Lambda (GMT960) platform took over the mid-size segment with its crossover, unibody design. This means that, if true, this would be a return of the Jimmy in its “proper form” in the eyes of enthusiasts. Especially after the “disappointing return” – in the eyes of those same enthusiasts – of the Blazer with the C1XX mid-size crossover platform, the same as the current GMC Acadia.

Body-on-Frame vs Unibody Pickup

So, what’s the big deal? Why is it important for SUV and GMC enthusiasts that it has a body-on-frame rather than be a unibody crossover. While there are advantages in using a unibody chassis – namely the weight saving, manufacturing, and rigidity advantages – there are advantages to the body-on-frame design that the unibody can’t match. At least not without drastic engineering and designs for a pickup truck design where the body and bed are a single piece. Of those advantages, the body-on-frame’s load bearing and towing capacity limits are much higher and is specifically why it’s still used on pickups and trucks.

This is because the body-on-frame rails can be strengthened in high-stress areas far easier when compared to unibodies. This is done through a combination of high-strength steel in the chassis as well as more cross members behind the cab. While this can be done on a unibody with additional bracing, doing so creates different torsion points along the chassis and can cause body failure in a unibody pickup truck design.

With the traditional design of the body and bed being separate pieces and isolated from the chassis with a body-on-frame design, each area can flex and move which reduces stress on each. It also means that the advantage of the unibody being a more rigid and structurally integrated with the entire body is a flaw in towing and off-roading. If it doesn’t flex, the body will overstress and fail without the addition of something to redirect or reduce the stresses in torsion.

Sail Pillars

That’s why the Chevrolet Avalanche (despite being a body-on-frame truck) and original Honda Ridgeline had “sail pillars” between the cab and the bed. This helped both vehicles take the torsion by spreading it through the main cab area. This reduced torsional stress between the open bed and the body to prevent cracking and/or failing of the body and chassis.

While the Avalanche was body-on-frame, it was also a single-piece body and bed design. Without the sail pillars, it too would have had body failure due to torsional stresses during towing because the bed area and body couldn’t move separately.

Sail Pillarless Ridgeline and SUV Advantages

The current Ridgeline features strengthening areas where the bed and body sections meet at the chassis and separate the “bed” quarter panel skin for this exact reason. These points and extra welding have removed the need of the sail pillar on the 2017 and up model, while also making it look more like a traditional pickup than the previous Ridgeline.

However, SUVs don’t have that disadvantage in a unibody design. Since they have a D-pillar by its two-box design, the load and torsional stress is spread over the entire body structure, just as it is with unibody trucks with sail pillars. There is no weak point due to a large space missing due to an open bed. With both the SUV and improved 2017 Ridgeline, the weight saving advantage of the unibody over the body-on-frame is erased when it comes to engineering for torsional stress while towing.

Would the 2020 Jimmy Really Be a Body-on-Frame?

While Car and Driver predicts it won’t end up being a unibody because it would compete against the Buick Encore and Encore GX, we must disagree on that being the reason. It wouldn’t make sense as the Encore GX and Encore are built for different segments than Jimmy buyers.

If anything, we won’t be surprised to see it as a cousin on the C1XX platform of the Chevrolet Blazer, GMC Acadia, and Cadillac XT5. Though, that may mean getting rid of the GMC Acadia nameplate as it’s built on that platform or a change in platform for it. It may also debut on the Vehicle Set Strategy (VSS) with the VSS-S (VSS SUV) platform to drop by 2025. The VSS is the four platform strategy that GM is looking to use to help reduce development time and time to market; improve efficiency in engineering, manufacturing and purchasing; increase margins for GM; and improve relations with key suppliers by having similar platforms to build parts for.

AT4 – Good Looking and Functional Package, But Not A ZR2

What we do agree with C&D is the need for a Canyon that equals the Colorado ZR2. However, GMC wants the AT4 to be the top nameplate for their 4WD lineups as they have showed with the Sierra AT4. Going back to the Acadia, there will be an AT4 version of it in 2020 and replaces the All-Terrain Package version. The Canyon should also get this level but we’d like to see it be the equivalent to the ZR2.

Currently, the AT4 versions from GMC aren’t ZR2 equivalent. For the Sierra, it does get a lifted suspension but only gets a set of Rancho shocks along with some black chrome and body color trim pieces as well as special edition wheels on Goodyear Wrangler All-Terrain tires.

The Acadia AT4 is an “inspired” trim with a 3.6-liter V6, twin-clutch AWD, and 17-inch All-Terrain tires along with the trim treatment like the Sierra AT4. No DSSV suspension or other hardcore treatment but that’s not what the AT4 was meant to be, either. It’s an upscale but fairly capable all-terrain vehicle.

A Colorado-based SUV Isn’t A New Idea

Even though we don’t think there will be a Jimmy based on the Colorado, there is precedent of a SUV on the GMT 31XX platform – the platform the Colorado/Canyon are currently built on. Over in Southeast Asia and the Middle East, there is the Chevrolet Trailblazer while it’s known as a Holden Trailblazer in Australia (originally known as the Colorado 7). This is potentially why a body-on-frame 2022 GMC Jimmy SUV looks plausible to C&D – the idea already exists. Its body lines and design are also very GMC-like, too.

It also has a Z71 package with a 2.8-liter Duramax engine, six-speed transmission, underbody armor, and shift-on-the-fly 4WD. It doesn’t have the Multimatic DSSV shocks, though. A major difference is that it uses a five-link rear suspension which is unlike the Colorado that uses leaf springs on its solid axle.

The VSS-T

The only mid-sized SUV planned for the upcoming VSS-T platform, however, is the international market Trailblazer. That being said, it’s not the only SUV to use it. The VSS-T platform is going to replace both the GMT 31XX of the Colorado/Canyon and International Trailblazer and GMT T1XX that underpins the Silverado/Sierra and Tahoe/Suburban/Yukon.

As we also mentioned earlier, there is still the VSS-S platform to drop soon. For now, the GMC Acadia and Acadia XL are the only ones listed to use that platform. There is also the GMC Granite and Terrain, but these might be a part of the VSS-F (VSS Front-Wheel-Drive). Even so, both the VSS-S and VSS-F platforms are crossover SUVs, not body-on-frame vehicles.

A Jimmy Is Coming

IMAGE: Automotive News - NOT A CAMO'ED JIMMY, just here for emphasis.

So, again, the evidence is strong the Jimmy will return with even GMC saying so. They just haven't provided specific details on the return yet. There is a mid-sized, body-on-frame SUV planned on the VSS-T for the international market but could easily be brought here. However, the current and future Blazers are both crossovers with the future version going to the VSS-S platform. This could indicate that the Jimmy will also go this course, but maybe not.

IMAGE: Car and Driver, 2022 GMC Jimmy Render

The Jimmy is coming; we do know that. We just don’t know for sure if it will be the VSS-T platform as Car and Driver says it could be or if it will be the VSS-S that crossover SUVs like the next Chevrolet Blazer will use. We will give Car and Driver credit, though. Their artist came up with a great looking idea of a hopped up 2022 GMC Jimmy if it does go the VSS-T route.