The letter code in the tire size and rating column is also on the sidewall of the tire and the tire label; tires are the same size, but compound and construction will vary to suit the weight, horsepower and handling characteristics of the model for which each tire was designed S-rated for speeds up to 112 mph, H-rated for speeds up to 130 mph, V-rated for speeds up to 149 mph, W-rated for speeds up to 168 mph