FYI: Tire speed, treadwear, and traction ratings

Speed Ratings

Q = 100 mph max
R = 106
S = 112 
T = 118
U = 124
H = 130
V = 149
Z = 149+

Speed Rating Myths 

1. The higher the speed rating the softer the tread compound.
2. A lower speed rated will always wear better than that of a higher speed rated tire.
3. The higher the speed rating the better the performance.
4. The lower speed rating will always give the best ride quality. 

Speed rating is based only on the maximum speed a tire (not a vehicle) is capable of sustaining in optimum road conditions.

Tire Traction Rating

• Tire Ratings - Traction grades Traction grades are an indication of a tire's ability to stop on wet pavement. A higher graded tire should allow a car to stop on wet roads in a shorter distance than a tire with a lower grade. Traction is graded from highest to lowest as "AA", "A", "B", and "C".

Treadwear Rating

• The higher the rating, the more miles they are rated for use over. A "440" tire will be good for many more miles than a "260."