If you have two tires with treadlife remaining, and two that are toast and need replacing, the better tires should be installed on the back of the car – across the rear axle. The older tires with life remaining should stay at the front of the car, or be rotated up to the front when the new tires are mounted.
Tires provide the most traction in hazardous road conditions (wet, slushy, snowy) when they are new, and have full tread depth. By placing the newer, better tires on the rear of the car, we're maximizing the control and traction available at the rear wheels and keeping the rear of the car as stable and planted as possible.
For most typical, everyday drivers, a loss of control at the rear axle isn't something that’s easily managed. A loss of traction at the rear of the vehicle often results in a spin, and/or an unwelcome off-road adventure – while if the front tires “wash out” due to a temporary loss of traction, driver intervention isn't generally as urgent, or quite as difficult.
You might be thinking, deciding which end of the car I want to have maximum control of isn't particularly appealing. We hear you.
If you do regular tire rotations and the vehicle is properly aligned, then tire wear should be pretty even for all four tires. However, in many cases people don’t keep up with these tire services, which means they may need to replace two tires at a time. Since most of us don’t want to “waste” tire life and unnecessarily spend money on two additional tires, the choice of where to put the new tires comes up.
If the remaining tread on the two usable tires is minimal, we recommend that you replace all four tires. With this fresh start, commit to regular tire pressure checks, tire rotations, and vehicle alignments and you’ll be able to make the most of your new set of tires.