[killroy]

Unless you are buying racing slicks, the rubber in a street tire should last at least a few years on the road. Of course tire life is shortened by tread wear and flat spots from sitting for extended periods.

As long as you follow a few minimum precautions like BenL suggests, their shelf life should be very long, at least five years.

If you intend to race at high speeds, I would reccomend using a tire up to 2 yeaars after manufacture (not purchase). Safe tires are very important at 150 mph+.

For a road car that rarely exceedes 100 mph, a five year old performance tire should be fine.