Why put new tires on the front of a car rather than the rear? I can certainly answer that. What I can’t answer is why Costco and Michelin would recommend the opposite!
In this short article I’m going to explain the benefits of putting new tires on the front of the car, and relay and rebut the Costco/Michelin argument for installing tires on the rear.
There are two main reasons for putting new tires on the front of the car:
Front tires wear faster for four reasons. One reason is that most of the vehicle’s weight is in the front of the car and that causes the tires to wear faster. Another is that most of the vehicle’s braking force is handled by the front brakes and wheels. The harder you brake, the more braking is done in the front. Next, nearly all of the turning loads are borne by the front tires. And finally, the propulsion loads are transmitted through the rubber in the front, assuming the car is a front wheel drive, and about 90% the cars we work on are front wheel drive.
The goal is that all 4 tires on the car wear out at the same time. Ideally a car would have four tires of the same brand, model, and size. If all four tires wear out at the same time, it’s easier to accomplish this, since tire manufacturers discontinue and add new models every few years. A tire model purchased a couple years ago may not be available anymore. If we put new tires on the front, they’ll eventually “catch up” to the tread wear on the rear tires.
As far as I know, Costco and Michelin don’t disagree with anything I’ve said up to this point. Here’s where we start to disagree though. In my opinion traction in the front is more important for safety than traction in the rear. Michelin believes the opposite.
The assumption here is that tires with better tread will be less likely to slip. This may or may not be true. It depends on it’s age, original traction characteristics, and whether or not the road is wet. For the sake of this argument let’s just say that deeper tread means better traction, which is certainly true if there’s standing water on the road.
If the front of the car loses traction in a turn, the nose of the car points to the outside of the turn. This is “under-steer”. If the rear of the car loses traction in a turn, the nose of the car points to the inside of the turn. This is “over-steer”. Turning too much is easy to correct. Turning too little is hard to correct.
Check out the video below. It’s cars racing in circles on a muddy track. Mud is slippery. Note that there’s not a single front wheel drive car in the bunch. Why not? When a car accelerates the load may cause the tires to lose traction. If the drive wheels were on the front, every time the driver accelerated and lost traction, the car would under-steer and head toward the wall. The driver’s are all easily pointing their cars using their gas pedals. Over-steer? Less throttle. Under-steer? More throttle.
Dirt Track Racing (Part 1) | Iowa State Fair 2013
If Michelin were right, and grip in the rear were more important, front wheel drive cars would dominate most types of racing, but the opposite is true — almost every type of race car is rear wheel drive.
Here’s one of Michelin’s videos with dramatic footage of spinning out. I’d argue that the spin was due to feigned poor driving technique. Michelin seems to think that if the good tires are on the rear the driver will feel the steering wheel become loose when the tires break traction and respond appropriately, avoiding the spin. Somehow Michelin thinks the same driver will be unable to feel the rear of the car sliding. I don’t know. It doesn’t make a whole lot of sense to me. I’d think that either the driver is going to feel both or neither, and either have driving skills or not.
Install Two New Tires on the Rear Axle
Michelin’s argument focuses entirely on turning. What about braking? What about accelerating? Let’s start with braking. I don’t have a production crew for a video, so you’ll need to put your imagination hat on.
A toddler is on the sidewalk clutching a squirming puppy almost as large as her. The puppy wiggles free and runs into the street.
Cut to a car driving down the street toward the adorable puppy. The driver slams on the brakes and tires screech.
Cut to to the little girl’s face, contorted with an indescribable look of shock, horror and despair.
Did the puppy survive? Is the girl scarred for life? It all depends one whether you are an “informed consumer” as Michelin puts it. When panic braking almost all of the braking is done in the front; that’s where you want the sticky tires. Don’t be a puppy killer, insist Costco install your new tires on the front!
We’ve covered cornering. Michelin says rear. I say front.
We’ve covered braking. Michelin omitted any mention of this because it destroys their argument.
Now let’s cover acceleration. If the car’s power exceeds the tire’s traction, the wheel spins. Whether it’s better to have the tires on the front or rear depends on whether the car is front wheel drive or rear wheel drive. This is the least important factor unless you’re drag racing or trying to kill puppies. That said, most of the cars we repair here are front wheel drive, so putting the tires on the front is the best option.
As you may have guessed, we sell and install tires. We’ll put our money where our mouths are and install them on the front if you don’t have any objection. Want them on the rear? Hey, no problem. It’s actually not all that important. Either a tire is safe and legal to use or it isn’t. Whether it’s on the front or rear doesn’t matter that much, and it’s certainly not life or death.
We also rotate tires, which you should do every 5,000 – 7,500 miles to wear all four tires evenly, and align vehicles, to prevent your new tires from wearing out prematurely.
By: Matt Wetherington
In an ideal world, motorists who need new tires would always buy a complete set of four at the same time. However, for various reasons, many consumers purchase two new tires instead of four. If you are here for a short answer on where the two new tires should be installed, always place the new tires on the rear when buying two tires instead of four. For the long answer, read on.
If you are replacing a pair of tires, it’s important to understand where the two new tires should be mounted. Unfortunately, there seems to be a lot of confusion about this issue. Most tire experts recommend mounting the two replacement tires on the back in virtually all circumstances. However, according to a study conducted at North Carolina State University, approximately 75 percent of all drivers think that if they have a front-wheel drive vehicle, their two new tires should be mounted on the front end.
In some ways this belief is logical. After all, in a front-wheel drive vehicle, the front tires are responsible for steering, transmitting acceleration, and most of the braking forces. Because of the stresses placed on them, the front tires of a front-wheel drive vehicle normally wear faster than the tires on the rear. This is why car manufacturers recommend periodically rotating a vehicle’s tires – to keep the tread wear on all four tires more or less equal throughout their lifespan.
When a vehicle’s rear wheels lose their grip on the road, the driver’s ability to maintain vehicular control is severely compromised because of oversteer (an occurrence that’s also called “fishtailing”).
Oversteer (and the loss of control it can lead to) “occurs in many rollovers and single vehicle loss-of-control accidents.” It is far more difficult to control than understeer, which occurs when a car’s front wheels lose grip. The risks associated with oversteer are severe enough that the tires with the better tread (i.e., a pair of new tires) should always be mounted on the vehicle’s rear wheels. There are “virtually no exceptions to this rule.” Sadly, most consumers have not been made aware of this important tire safety principle.
When tire failure occurs – even of the hydroplaning or oversteer variety – the result can be severe injury or death. To reduce the likelihood of this happening, experts recommend replacing tires as and when needed, but at a minimum, every six years is a good rule of thumb. Often, replacement is done in pairs, but the new tires are frequently mounted on the front. This is an unsafe, dangerous practice.
Tire manufacturers have a responsibility (ethical and legal) to educate consumers and communicate tire-related safety information and precautionary warnings. Given the importance of mounting new tires on a vehicle’s rear wheels, the potential risks involved with putting them on the front instead, and the dearth of exceptions to this rule, tire manufacturers and retailers must clearly inform consumers that no matter what, a new pair of tires should always be mounted on the rear.