The Toyota bZ4X is going back on sale now that Toyota has figured out how to keep its wheels from falling off. Toyota will resume production of the fully-electric crossover on Thursday, now adding washers to its wheel hub bolts. Toyota will then resume sales on October 26 in Japan, with bZ4X sales in the U.S. following shortly afterward, as Automotive News reports.
Two months after the debut of the Toyota bZ4X, the Japanese auto giant issued a recall of its EV crossover because of a production defect could lead to the car’s wheels falling off. The recall traced to the high torque of the bZ4X’s electric motor and its effect on the EV’s wheel hub bolts.
These bolts are supposed to fasten the wheel securely to the car, but the bZ4X’s torque was literally more than its wheels could handle; under certain driving conditions, such as turning sharply or braking hard, the bolts could come loose, and the wheel could come off completely.
To make matters worse, the weight of the EV’s battery pack added strain to the wheel hub bolts, making it harder for these to stay tightly fastened under abrupt acceleration and deceleration.
Toyota is fixing the defect by adding a washer to the hub bolts and improving the friction of the wheel surface, per AN. Toyota will also confirm that wheel surfaces adhere to stricter quality processing, and verify that replacement hub bolts are properly tightened during assembly, according to Reuters.
Toyota is basically just strengthening the mechanical connection between the EV’s wheel hub and its wheels, and will reportedly apply the same process to all of its EVs in the future. That includes any EVs that Toyota produces with other carmakers, such as the Subaru Solterra.
The global recall issued in June affected about 2,700 models of the Toyota bZ4X and 1,600 models of the Subaru Solterra. In the U.S., there were 258 models potentially involved, although there were only two reports filed that confirmed the defect. Toyota told bZ4X owners to stop driving their cars, and offered to buy back their EVs. It’s unclear how many owners heeded the carmaker’s notice.
Toyota’s Chief Technology Officer Masahiko Maeda explained more about the company’s misstep, adding that Toyota will be decisive in solving the issue:
It is embarrassing to say that we had done various assessments but we couldn’t detect this problem because we didn’t conduct the assessments based on a premise that the quality of wheels would be so off in the assessment process, [...] We will respond firmly to regain trust in the [safety] of Toyota vehicles.
Applying washers to the hub bolts seems like a simple fix, but Toyota did not specify what the bZ4X recall will cost. With so few cars involved, it may not be much but it’s nonetheless a setback for the company. One that could cost Toyota in other ways — namely, in that of buyer confidence. The company has been criticized for lagging behind its competitors during the EV transition, and a recall for a safety issue is far from ideal for the company’s modern EV debut.