I just had the rear tires replaced on my 2008 Escape. It is a 4WD version. The rear tires were all cracked around the circumference of the treads. The salesman tried to sell me all four tires, but since the tires in the front are not cracked (and a year or two newer), I declined. He said because it is all-wheel drive it is better to buy all four, but couldn't give me any further explanation.



Nevertheless, now that I am home with my new rear tires I am wondering if I should have splurged and got all four. We only put about 8000kms per year on this vehicle and no highway driving. New tires are a different brand, have same basic tread pattern and are the same size as what's on in front.

Does anyone think I'll be okay for the upcoming winter or should have bought the whole set?

Thanks,
Andrew

 

The reason they recommend replacing all 4 tires is ; If all 4 tires are the same circumference it puts less wear on the differential assy for all 4 wheels..

 

I know this is a somewhat old thread but I'll post anyways for future people. It can take out a transfer case if the front and back tire are different tread amounts. It only matters if you can't turn off awd like all escapes usually are, if you had a truck with a switch to turn it off then you would be fine. I worked at a tire shop and someone came in with an awd vehicle and we recommended that he replaced them all and he said no just 2 and so we did it. We saw him at a later time and he said you were right, I should have got all four becuase I just spent thousands of dollars having my transfer case rebuilt. That's obviously the worst case scenario but for an extra little bit I wouldn't risk it.

 

Not so sure about this story, perhaps it was just coincidence rather than causation? I would find it very hard to believe that an 1/8 inch of tread would make that much of a factor between partially used tires on one end and new tires on the other end if they are the same brand and make of tire.

I am more inclined to think it may be related to the pattern and grip of the tires seeing in wet/snow conditions that would play a bit more havoc with the AWD system, so i personally would be as concerned with coefficient of traction due to tread compound of the tire. I would not use different type of tires such as winter & all season mix, or different brands and tread as i see that as effecting the AWD system.

In any case best not to mix and match, the further out of whack they are to each other the more of a concern imho. You are right however even tire shops take their best case guess however haven't seen it stated for a fact just that manufacturers state that it is important to match all four tires.

 

Just in case one is not familiar with differential ratios , (the number of turns a driveshaft must turn to get one rotation of a wheel ) adds up when covering many miles.
That accumulation becomes evident when we look at the differential between the front and rear when tire circumference is measured. You could have the same size and brand tire, but if one is a different circumference due to wear They do not cover the same distance if the number of rotations is the same. The mechanism to allow for that is the differential and in the case of all wheel drive, that is why they put a differential assy in there.

 

Strictly speaking, replacing all 4 tires at once is your best bet. Budget constraints mean that it's not always possible though, so you can get away with just replacing 2 tyres at a time provided there isn't a huge difference in wear between them (as discussed above). If there is a huge difference between the new and the old tires, you should probably be replacing all 4 anyway.