This Is Why Tesla’s Stainless Steel Cybertrucks May Be Rusting

Who knew stainless steel might not be such a good idea for the exterior of an electric SUV? The entire automotive industry, that’s who.
Tesla Cybertrucks parked outside
Photograph: SUZANNE CORDEIRO/Getty Images

During the Cybertruck's unveiling in 2019, Tesla CEO Elon Musk claimed that the electric vehicle's "ultra-hard stainless steel" body might be "literally bulletproof." However, the Tesla truck's exterior panels appear to be defenseless against water pistols. They apparently rust, as some owners claim.

Posting on the Cybertruck Owners Club forum, a user named Raxar risked the wrath of the Tesla faithful—already exercised by the Cybertruck's numerous alleged design flaws—by stating that when they collected the $61,000 truck, "the advisor specifically mentioned the Cybertrucks develop orange rust marks in the rain."

In a separate thread, the user vertigo3pc reported that "corrosion was forming on the metal" of his Cybertruck after it spent 11 days in the rain in Los Angeles.

Raxar, who also lives in California, posted what appeared to be close-up, rust-flecked images of his truck after driving it for two days in rain.

The Cybertruck does not ship with clear coat, that outermost layer of transparent paint that comes as standard on almost every new motor vehicle on the planet. Instead, each Cybertruck owner has the option to purchase a $5,000 urethane-based film to "wrap your Cybertruck in our premium satin clear paint films. Only available through Tesla."

Photograph: Andrej Sokolow/Getty Images

Who knew untreated stainless steel might not be such a good idea for the exterior of a motor vehicle, especially considering that cars typically get left sitting outside in all weather for 95 percent of their lives? The whole automotive industry, that's who.

Aside from the 1980s DMC DeLorean and a shiny 1960s Porsche, car companies have long steered clear of stainless steel panels. The material is heavy, relatively expensive, and hard to work with. It's also stiff, which makes it potentially more lethal to anybody unlucky enough to be struck by a vehicle built with the stuff.

Stainless steel also stains. "Stainless" does not mean "never stains," just that it stains less than other steels.

Tesla says it uses proprietary stainless steel (possibly from Outokumpu of Finland, Europe's largest producer, which runs a plant in Calvert, Alabama). However, even proprietary stainless steels can stain, especially if any cheaper steel fittings beneath the Cybertruck's panels react with the stainless product.

There are five basic families of "stainless steel": austenitic, ferritic, martensitic, duplex, and precipitation hardened. Some containing chromium among other constituents, such as nickel and molybdenum, are more corrosion-resistant than others, forming an impervious and protective molecular-scale surface barrier of chromium oxide.

Stainless steel discoloration usually takes the form of small, dark brown pits on the steel's surface. Exposure to sea salt and high temperatures can be one cause of such pitting. Some parts of California, a hot state with a 1,264-mile coastline, might, therefore, be worse than others for causing the orange flecks reported by Raxar and others.

Once the chromium oxide barrier is breached, corrosion takes hold. And caveat emptor, because Tesla's owner's manual advises promptly removing corrosive substances, emphasizing not to wait until the Cybertruck is scheduled for a "complete wash," whatever that is.

The documentation says: “To prevent damage to the exterior, immediately remove corrosive substances (such as grease, oil, bird droppings, tree resin, dead insects, tar spots, road salt, industrial fallout, etc.). Do not wait until Cybertruck is due for a complete wash. If necessary use denatured alcohol to remove tar spots and stubborn grease stains, then immediately wash the area with water and a mild, non-detergent soap to remove the alcohol.”

Pigeon poo is a well-known corrosive agent—guano is no friend to the fastidious car owner—but tree sap and bugs? Maybe that $5,000 Cybertruck wrap should ship as standard.

Other care instructions—highlighted in this YouTube video at 23 minutes in—reveal how delicately Cybertruck owners need to treat their stainless steel electric SUVs. The washing stipulations alone include, somewhat amazingly, “Do not wash in direct sunlight,” “Some cleaners and car shampoos contain chemicals that can cause damage or discoloration,” and even “Do not use hot water.”

Tesla was asked to comment on this story but did not respond.