ATLANTA - A reader from California asked where on a vehicle you should place tires if you are only purchasing two new ones.

Based on years of teaching vehicle dynamics in driving classes, I say put them on the front.

A vehicle accelerates, brakes and steers. Two of those functions take place primarily on the front wheels, so that is where I would want the maximum traction. On a front-wheel-drive vehicle, all three functions take place on the front wheels.

But tire engineers at both Goodyear and Michelin, much to my surprise, said new tires should go on the rear.

They explained that not having enough tread on the rear of a vehicle, especially in wet or inclement weather, could cause the driver to lose control of the vehicle.

Because most high-performance cars don't have the same size tires on the front and the rear, they acknowledged they were talking about basic passenger vehicles and SUVs.

I questioned how could you worry about oversteer (the rear end coming around) on a front-drive vehicle when they have understeer engineered into them. But one engineer said the real problem was how a driver would react to any unexpected situation.

The first reaction is to step on the brakes. That is the last thing you really want to do.

More than providing the optimum position of the tires, they were advocating what they saw as the safest decision for the bulk of drivers. Of course, both engineers said the best solution is to purchase four tires at a time.

While I appreciate their position, I'd still put the new tires on the front. I'm much more worried about being able to steer and stop than I am about the rear end breaking loose. For that to happen in the bulk of today's passenger vehicles, you would have to be driving way over your head anyway.

Besides, I have learned that you can control the back of the car by decreasing your acceleration, not by stepping on the brake.

So now you know both sides of the story.

Linda Sharp is a training consultant to auto manufacturers.