Do I really have to replace all four tires on an all wheel drive 2007 Ford Fusion when one is destroyed?
A lot of it depends on how much tread is on the other 3 tires . Without knowing the measurements it is hard to answer the question . Is that what the tire shop said?
Is this th car you would take on road trips? If so I wouldget the same size make and model tire and have it shaved to match the others, but only if the others had at least 60% or the tread depth left.
If this is a second or around town car, I would look for a tire that matched the circumference of the other 3. Biffer brand or model of tires vary even in the same nominal size or even find a good used tire.
If replacing all four tires were required that statement would be in the owners manual but it is not. For the most part it is a myth, most vehicles do not require all four tires to be replaced. Only some vehicles like Subarus do not allow much variance in tire diameter because of the center differential design…
What I really want to know is what’s the worst that could happen if I just replace the one tire with same size new one?
The worst is drive line damage . But you still have not gave the tread measurements of the remaining tires or the age ( tires also need to be replaced by number of years in service ) or what the tire shop said. I myself would at least put 2 new tires on the rear but with so many buy 3 get four deals out there why not do that.
If the other three are near the end of their tread depth life, why not replace all 4 and be done with it. If they are near new with almost new tire tread depth, then just get one.