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According to the Owner’s Manual Saab 9-3 M2001 (front-wheel driven cars):

WARNING When fitting just one new pair of tires, these should be fitted to the rear wheels, as these are more critical to the directional stability of the car (e.g. on braking or in a skid). The existing rear tires should therefore be moved to the front. Always move left rear to left front and right rear to right front, so that the direction of rotation remains the same.

This is somewhat counterintuitive to me. Is it indeed recommended (by other sources) to have the least-worn tires at the rear wheels?

Řídící
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2 Answers2

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From what I have seen and read over the last few years the "general rule" has become best tires on the rear. In my opinion it is likely the result of litigation by people who were involved in skidding accidents. The theory as far as I understand it, is that with worn tires in the rear, the back end can loose traction and allow the rear of the car to attempt to pass the front while in a high speed turn or emergency braking situation. Any resulting inability of the driver to steer into the skid would become an inherent design defect when the case comes to court. I assume it has been determined by lawyers that it is safer to get stuck in snow because the best tires are on the back, than risk an incident of the back end coming around because you were going to fast in the first place.

mikes
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It really depends on the car... and I mean on which wheels is the traction.

Usually front wheel traction cars should have the better tires on the front wheels. But that doesn't mean that having good on front and highly used on the back makes it safe. The problem is that with usage, the technical caracteristics of the tire change and if a tire is tested to stop in 60 meters (for example) from 40-0 mph, a worn down tire will do it in 70 meters. This will cause an imbalance between the front or the rear. Fortunately many modern cars have ABS and the ABS sensor improves stability and safety even though there is a difference in the tires. From experience I do not recommend changing tires 2 by 2 because this will wear down the new tires faster than usual.

If your example is the Saab 9-3 (I had a convertible one :) ) then I recommend to have the least worn tires on the front because it's a front wheel traction car. If your car is a BMW, then having good tires on the back is more crucial. (Especially in winter time) Also it is very important to have winter tires in the winter, as the physical characteristics of the tire are different ("summer" rubber is made to be sticky, but at low temperatures it becomes hard, so if you have worned out summer tires on the front wheels and driving on the highway in a cold winter day, it is highly possible that you will turn the steering wheel and nothing will happen).

Sebastian Rosca
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