All tires (including spare tires) that were manufactured more than ten years ago should be replaced with new tires, even if they appear to be usable from their external appearance and if the tread depth may have not reached the minimum wear out depth.

There are a number of considerations when buying tyres but lets start with some of the key points.

Everything You Wanted to Know About Motorcycle Tires. From radial tp bias, tire dating, tire pressure and tire selection, it is all right here.
Curious about those round rubber things attached to your wheels? We have some answers for you

This How To Balance Motorcycle Tires article will help make sure the wobble wont happen to you.