“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, because 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, because they are likely to perform differently, creating an imbalance and adversely affecting 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.
