My car is 3 years old. The spare tire (full size)has never beenused. I need new tires. Can I use my spare as one of the new tires, and only buy three, or is this a bad idea?
If after inspection the tire is ok, and it is on the same rim as the rest of the car and you buy the same tires as the spare is I’d say go for it, then use your best old tire as the spare. As an added safety I would put it on the back as it would be the most prone to failure, and blowing out a rear tire is safer than blowing out a front tire.
In order to do it right, you would need to pair it with an identical tyre on the same axel (front or back) and the two tyres on the other axel should be very similar.
I assume your plan is to buy three tyres and use one of those now on the car as a spare?
If you liked your OEM tires(factory ones) then it is a possibility. Many times the factory tires leave something to be desired in terms of price, performance or longevity. Do not purchase 3 new tires of a different model. Make sure all 4 match.
What they said - this trick was in a Popular Mechanics back in about 1965…good idea then, good idea now. Just use the best of the 4 old tires for the spare.
What kind of vehicle is it?
I wouldn’t do what you are considering. In any case, you will be buying four tires, no matter which four you replace. There is no real savings by doing it your way.
Is the tire stored under the vehicle where it is exposed to the elements or is it stored in the trunk? If it is stored in the trunk, it will be safe to use as a spare for another eight years or so. If it is exposed to the elements, it will be safe to use as a spare for another three or four years.
Using your spare will be OK, no problem. Just mount it on the rear to avoid any slight steering differences between it and the similar tires you buy. There are no “issues” here except ones people make up or read about in Road & Track then parrot here…You don’t have to match the spare tire EXACTLY. Just match the size and type of tire.