DIY Tire Changes Are Risky: Nationwide Spike in Cars Falling Off Jacks — Causes and Prevention Tips Explained

Causes of the increase in tire road accidents

Vehicle wheel detachment accidents have been occurring one after another—

On April 27, in Nagano City, Nagano Prefecture, a tire came off a car traveling on a prefectural road and crashed into a nearby taiyaki (Japanese sweet) shop. Four people—a 4-year-old boy, a 6-year-old boy, a 15-year-old high school girl, and a 49-year-old woman—who were lined up at the shop were injured. On May 28, a similar accident happened in Nounai Town, Fukagawa City, Hokkaido, where a tire came off a wagon while driving.

“According to the latest data announced by the Ministry of Land, Infrastructure, Transport and Tourism, there were 142 cases of wheel detachment accidents involving large vehicles in fiscal year 2023. This is more than three times the number from 10 years ago,” said a reporter from a national newspaper’s social affairs department.

Why are such wheel detachment accidents happening so frequently? Hideki Kageyama, manager of the “Tire Center Toyotomi Namerikawa Shop,” pointed out, “One possible reason is that due to recent economic downturns, more people have been doing maintenance themselves rather than entrusting it to professionals.”

“Most cases of wheel detachment happen because the wheel nuts that fasten the tire to the vehicle come off. The cause is usually loosening due to insufficient tightening of the nuts. There are also cases where nuts that do not match the shape of the wheel nut holes are used, leading to detachment.

Tightening the nuts too much out of fear that they might come off is also bad. If tightened excessively, the bolts under stress can stretch or break while driving, which ultimately causes the tire to come off. Professionals understand this balance, but recently, as more people change tires themselves, inspections may be insufficient and proper installation might not be done. This has led to a trend of increased wheel detachment accidents.”

According to Mr. Kageyama, “Tire deterioration itself is also a factor causing wheel detachments.”

“As tires degrade, the wires inside break. Tires can become deformed or torn, which can lead to detachment.

Aside from wheel detachment, there are many accidents caused by insufficient air pressure. When the air pressure is too low, the tire’s contact surface flexes, weakening the contact areas at both the edges and center. This causes the tire to twist or distort, generating heat and leading to cracks. These factors can also lead to tire bursts. Each tire has a recommended air pressure value, so please adhere to it.”

Is there anything else that should be done to prevent accidents?

“Japan’s tire manufacturers boast world-class technology, but due to poor vehicle maintenance and a lack of risk awareness among drivers, the number of wheel detachment accidents continues to rise. I recommend having your tires replaced by a professional once every four to five years. For those who change their tires themselves, be sure to use wheel nuts that match the wheel’s specifications and tighten them with the appropriate torque.”

A detached tire is nothing but a deadly weapon. To avoid serious accidents, every driver must acquire proper knowledge about tire safety.