In May, the German newspaper Handelsblatt began reporting on the “Tesla Files”: thousands of internal documents provided to it by a whistleblower. Among those documents was an engineering report that might give some insight into why the vehicle has taken so long to come to market. The report, dated January 25, 2022, which WIRED has examined, shows that the preproduction “alpha” version of the Cybertruck was still struggling with some basic problems with its suspension, body sealing, noise levels, handling. and braking.
The contents of the report do not deal a fatal blow to the Cybertruck. As one veteran automotive engineer, who spoke on condition of anonymity to prevent backlash from Tesla fans, says, the company has enormous financial resources which will allow it to address the issues detailed in the report. However, he said, “my first reaction is I am astounded. These are classic mechanical automotive engineering challenges that you have in pretty much any vehicle. I'm blown away that they would be struggling so much with the basics.”
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The internal dynamics and NVH—noise, vibration and harshness—report leaked to Handelsblatt contains test results measuring the performance of the alpha version of the Cybertruck against projections made using computer-aided design (CAD) simulations, and against internal benchmarks. In summary, it presents a picture of a prototype vehicle that’s leaky, noisy, and has poor handling and braking.
“It’s an alpha-stage vehicle, so it's not surprising that it’s some way off its targets,” says Andy Palmer, the former COO of Nissan and CEO of Aston Martin Lagonda, who has more than 40 years of experience in the automotive industry. Palmer says he’s surprised at the frankness of the report. “You’d be giving the engineers that wrote this stuff a good bollocking. You don’t normally write this down.”
The report says that the alpha version of the Cybertruck had to be hand-sealed, but that “there are a number of areas that we do not have a clear path to sealing” in a production version of the vehicle. This is an issue not just for keeping the weather out, but for noise in the cabin. Data in the report shows that the alpha version was significantly noisier than engineers had projected based on their designs, and that testers had identified 21 potential noise leaks in the body of the vehicle.
Tesla cars have a history of leaking, and the report hints that the Cybertruck’s unusual design may have complicated engineers’ attempts to properly seal it. “Body manufacturing and paint shop processes have struggled to seal bodies for optimal NVH performance in the past, and the Cybertruck design presents new challenges,” the report says.
Handling was also a concern for the alpha Cybertruck. The report noted a number of issues, including “excessive mid-speed abruptness and chop,” “high head-toss accelerations,” and “structural shake.” It said that the truck experienced “excessive lateral jerk during low-speed maneuvering” and that it needed to address problems with steering refinement and body roll. The EV’s strafe mode, a feature that allows the wheels to turn to allow the car to “crab walk” sideways had “only basic functionality.”
Braking performance was one of the worst areas of the report. Tesla’s engineers were aiming for a score of 7, or “fair,” on the Society of Automotive Engineers rating scale, but the alpha version achieved only a 4, or “poor” rating. According to the report, in January 2022, the Cybertruck’s brake pedal pressure pad was still under design, and so the alpha experienced “excessive pedal travel and inconsistent stop,” and “excessive pitch during friction braking,” braking during turning issues, as well as power braking instability.
“The brake performance seems serious. I’m surprised they’re not further forward,” Palmer says, after being apprised of the content of the report. Normally, the chassis, including the braking system, is the first thing that engineers work on, ahead of the body and other systems. “So to be only on prototype parts at this stage is quite late.”
The report also details the results of kinematics and compliance (K&C) testing, which is used to evaluate the ride and handling performance of an automobile. During a typical K&C test, the vehicle body is fixed while controlled forces or displacements are applied to the wheels. The results of such tests yield vehicle suspension parameters, such as camber and toe, a measurement that determines how much the wheels are turned in or out from a straight-ahead position. The report showed that the alpha Cybertruck’s performance showed a “significant gap to targets.”
The report lists problems against potential solutions, some of which are illuminating. The front of the vehicle had some issues where there was “no solution without modifying suspension design.” Against the problem of “too high camber gain,” resulting in, among other things, tire wear and alignment change with ride height, the entry on the solutions column bluntly states “possibly none.”
There are indications within the report of the problems that Tesla has had in building a truck that can compete with other electric vehicles in its category.
Torsional stiffness is the ability of a car’s body to withstand twisting. When turning, if the torsional stiffness is too small, the body will fail. Too large, and it will be difficult to turn and tend to understeer. The alpha truck’s performance was significantly off target, which might be concerning for Tesla, according to Palmer. “What's surprising about that is it's really hard to fix. It's fundamental. In your development, you can simulate it fairly accurately. So I’m surprised it's so far off,” he says. “It's a biggie, too, because fixing it adds weight and compromises the design of the vehicle.”
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On an earnings call on January 26, 2022, one day after the date on the leaked report, Musk announced that the Cybertruck would be delayed until “probably next year,” arguing that launching a new vehicle would disrupt the company’s production schedules. “If we were to introduce new vehicles, our total output will decrease,” Musk said on the call. Tesla has since pushed back mass production of the Cybertruck once again, to 2024, despite Musk declaring in a YouTube interview in July 2022, just five months after the NVH report, that the design was “finally locked,” adding, with an audible sigh, “We got too carried away.”
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