Unfortunately, it now appears that rear-drive Cybertrucks equipped with the base 18-inch steel wheels have potentially defective brake rotors that could lead to the wheel becoming detached. The recall itself also offers a revealing glimpse into just how poorly the Cybertruck RWD sold.

It’s difficult to know just how many Cybertrucks Tesla sells at any given time seeing as the company lumps them in with Model S and Model X deliveries. In Tesla’s quarterly reports, those vehicles are all grouped together as “Other Models,” while the Model 3 and Model Y are reported separately. This recall pulls back the curtain slightly, revealing that the recall covers just 173 Cybertruck RWDs with the 18-inch wheels (the truck was also available with optional 20-inch wheels, which aren’t part of the recall). With that now out in the open, it should come as no surprise that the model was canceled.

The Wheels Can Fall Off

This recall itself involves a potentially serious safety issue, namely that the truck’s wheels could fall off. However, the problem isn’t with the steel wheels themselves; it’s with the brake rotors. The holes for the wheel studs in the rotor can begin to crack due to “road perturbations” and stress on the hub assembly during cornering. If the owner doesn’t notice the cracking, which can easily be hidden behind the wheels, it could eventually lead to total failure, causing the wheel studs to separate from the hub and the wheel to come off.

The issue also isn’t limited to trucks built at Gigafactory Texas. Tesla service centers stocked the same rotors, meaning the defect can also appear after repairs. In many cases, those replacement rotors were installed because of similar cracking, sometimes after customers reported unusual brake pulsation. Until this recall was issued, Tesla says it was aware of only three warranty claims that “may be related” to this failure condition. Thankfully, the company also says it is unaware of any crashes, injuries, or fatalities related to the brake rotor and wheel stud failures.

New Hubs, Rotors, and Lug Nuts Are the Remedy

Tesla has developed redesigned rotors and wheel hubs that increase the contact area between the components and the wheel. The updated design is intended to reduce the stress loads that caused the original rotors to fail. Tesla has also introduced a new lug nut with a higher-friction coating to improve torque retention under heavy loads. Recall notices were sent to owners beginning April 24, but the replacement parts do not yet appear to be in stock. Remedy notifications are not expected to go out until June 20.

As with any recall, the repair will be done free of charge. Tesla notes that any similar repairs completed before the recall should already have been covered under warranty, which is why those owners will not be reimbursed.