when I consider buying 3 new Michelins to go with my full size Michelin spare that's less than 2 years old. Spare has been on ground once. Truck is rapidly approaching 60k, have one tire with a repair into the sidewall that they don't plan to work on again. It's started losing air again. I'm Thinking keep one of the three good ones for a spare, buy 3 matches to current spare? Or should I just spend the extra $150 or so?

 

good plan. No sense in wasting a perfectly good tire. Having an aged one as the spare should be fine.

 

If the spare looks good I would say go for it. Why not.

But if there is dry rot or it does not look good don't

 

If its all the same size, keep the spare the same