Elon Musk revealed the Cybertruck last night, saying it doesn’t look like anything else on the market. That’s true, but the Cybertruck shares several key features with an unlikely pickup: the first-generation Honda Ridgeline.
Both the Cybertruck and Honda Ridgeline are built differently than standard pads. They employ a monocoque design, very similar to that used in most passenger vehicles. Instead of a body sitting in a frame, the Cybertruck and Ridgeline are built around what is essentially a metal cage. A monocoque truck makes sense for Tesla, who doesn’t want a large, bulky frame under the body. Tesla wants batteries under the vehicle and uses his body to protect them.
Due to the unibody pickup design, the vehicle has to employ a key design element to enable high capacity towing: a sail pillar.
Very often, a vehicle’s towing capacity is limited by body design rather than engine power. The trailer puts a lot of stress on the vehicle frame. Do you want to throw more? Make a sturdy frame under the truck. But with the Tesla Cybertruck unibody, to increase towing capacity, he had to use a sail pillar as large as possible, which explains the unconventional design.
A vehicle naturally wants to twist. Consider wringing a washcloth. In a body-on-frame design, the engine rests on a large frame, which absorbs many of the stresses. In a unibody design, vertical mounts help and are used at all times, starting with an A-pillar next to the windshield and ending with a D-pillar in the SUV’s rear window.
With a body-on-frame design, like that used in most trucks, the strength of a trailer rests on the frame. Most of the energy is absorbed in the structure located under the body of the truck. The truck cab is decoupled from the bed, allowing the cab and bed to move relative to each other and better compensate for frame stress.
In a unibody design, such as in the Cybertruck, Ridgeline, or most SUVs, the body is subjected to the same forces, but you have to use the body to avoid twisting. The buttress-like sail pillar helps absorb energy and prevents the truck from twisting.
Unibody SUVs have D-pillars, the vertical supports at the rear of the vehicle, where the trucks do not. This D-pillar is necessary to prevent the body from twisting and bending when under load. But without the D-pillar on a unibody pickup, a sail pillar connects the C-pillar to the rear of the truck, achieving a similar result.
The first-generation Honda Ridgeline had a modest sail pillar, but Honda was able to get rid of the feature for the second generation by reinforcing critical points throughout the body.
Honda described the redesign like this:
The 2017 Ridgeline rear frame structure is vital to overall body structural rigidity, collision safety performance, and the Ridgeline’s towing and towing ability. Utilizing fully boxed frame members for the body sides and tailgate frame, the truss-style rear internal construction contributes to Ridgeline’s new, more conventional three-box design profile, allowing for frame removal Buttress-style body at the front of the top bed in the previous model, while contributing to a 28 percent gain in torsional stiffness compared to the previous model. Additionally, the U-shaped rear frame member serves as a highly rigid mounting structure for the tailgate, allowing for very precise adjustment of the tailgate.
The Chevrolet Avalanche also used a sail pillar to make up for the lack of a D-pillar. To do the avalanche, Chevy took a full-size Suburban SUV and cut the rear quarter.
It is unclear if Tesla released the final version of Cybertruck. We still have important questions. And if it’s not the final design, there’s a chance Tesla might be able to use some of Honda’s tricks to reduce the buttresses and produce a more conventional pickup design.