Should You Always Replace Car Tires in Pairs?

The answer depends on a few important variables

Mechanic putting a new tire on a car Photo: iStock

Flat tires tend to happen one at a time. The ideal scenario is to replace all four tires, but that can be costly. So to address a tread puncture or sidewall tear, can you buy just a single tire or split the difference and replace a pair?

The first thing to consider is whether or not your car is all-wheel or two-wheel drive. All-wheel drive cars have specific tolerances for how much your tires can differ in tread depth. Consult and follow your owner’s manual to avoid damage to the drivetrain. For two-wheel drive vehicles (either front or rear wheel) determine how much wear you have on your tires.

“If your tires are less than 30 percent worn you can get away with replacing just one tire and placing it on the rear axle,” says Ryan Pszczolkowski, Consumer Reports tire program leader. “If the tires are all approaching 40 to 50 percent worn, I would recommend you buy two of the same tires you already have and put the two new tires on the rear axle.”

Placing the new tires on the rear axle helps maintain safer and more predictable handling. As you approach 70 percent worn or more, you should just replace all four tires.

To maintain optimum and balanced handling, remember not to change the type of tire. For example, mixing a summer tire and an all-season tire, as this will cause an imbalance in the grip and disrupt the vehicle’s dynamic performance—something the automaker spent tens of millions of dollars to tune. Also, you don’t want to change the brand for the same reasons, as they are likely to perform differently, creating an unbalance and adversely affect your car’s handling.

There are some cases where it makes sense to replace one tire, says Pszczolkowski. If your tires still have 70 percent tire life, then buying one replacement tire makes sense because your other tires are still relatively new.

With tires, the decisions should always come down to safety, even if that means spending a bit more money to do the right thing.