Have you ever bought tires?
Here, you can compare all the specifications (temperature A-D, traction A-D, and treadwear 80-620* as a % of tread? wear, characteristics) of every manufacturer's tires!
Yes, you will need more informaton, but this is a start!
This list is compiled by the Department of Transportation, and you can find the rating of the tires you have on your car, now!
* 100% = some arbitrary amount (30,000?) of mileage for tread wear?
(Can some one explain this to ME!)
You can find all the information on the sidewall of your tire - if, IF, you have not worn it all off, polishing the curb!!! This habit significantly weakens the sidewall of your tire!