Among car enthusiasts, this question is definitely one of the most widely discussed. At the same time, there is a popular misconception that least-worn tires must be fitted on the driving axle, and, since the overwhelming majority of cars nowadays are front wheel drive, it stands to reason that the new tires must be fitted on the front wheels.
Indeed, oftentimes you can only afford to buy a couple of new tires. Of course, such situations must be avoided, and four new tires are always better than two new ones. However, the choice of where to put two new tires is faced by 100% of motorists during the seasonal swapping of tires.
So, why do you have to put least-worn tires specifically on the rear wheels?
This is needed to avoid emergency situations while driving because an unexpected abrupt maneuver can send your car into an uncontrollable skid of a rear axle. Should this happen, the state of the tires may make all the difference, especially if we are talking about wet or ice braking. The skid of the front axle, on the other hand, can be remedied by the right steering.
Also, if the front wheels are fitted with new tires, the driver may feel overly confident of themselves, which may lead to increased speed on a hazardous surface, and, as a consequence, a skid of the real wheels during an moderate emergency maneuver. Getting out of such a skid is something that only a driver with experience of extreme driving can do, and not everyone has such an experience.
A visual comparison of cars with new tires on different axles
Who gives such advice?
Advice to fit the least-worn tires on the rear wheels of your car is given by every major company in the tire industry. Such recommendations can be seen in manuals by Continental, Bridgestone, Michelin, and Goodyear.
These are joined by a number of major car makers.
Where are the arguments against these recommendations?
If you disagree with this point of view, think about this: it doesn’t matter what that buddy of yours did, «who’s been driving forever», and it doesn’t matter what makes sense and what doesn’t. I just challenge you to find one recommendation from a car or a tire maker to put newer tires on the front wheels.
Also keep in mind that if the difference between the remaining tread depths of the tires is more than 4 mm, such a combination of tires is downright dangerous, and you should probably think about buying a full-fledged set of four tires.