Tires: Z rated tires vs R rated tries, load index, speed rating

Question
Hello Expert,

I'm in the market for new tires for my Mazda 2006 6s; current tires on vehicle is 215/40Z18. When shopping for new tires I've come across rating of Z and R. From my understanding is that "Z" is a performance tire with speeds mentioned as 149 mph and "R" is a run flat if I'm interperting correctly.

For everyday all weather driving usage; does the ratings of the tires make a hugh difference?


Thank you,

Answer
Dino,

I think you are confusing terms.  The "R" means "Radial" - and the speed rating is usually expressed along with the load index in a thing called the "Service Description" which normally follows the tire size in a number/letter pattern, with the number being the load index and the letter being the speed rating - like this:  100W.

Typically the higher the speed rating, the better the handling, but the stiffer the ride.  However, there are enough exceptions out there to say this isn't nearly a correlation.

But the higher the speed rating the safer the tire.  Frankly, I think the minimum speed rating ought to be H.