INFINITI Tire Advantage
How to Read Your Tires
Your tires come with a unique code to help you determine what size they are (i.e. P215/65R15). The 'P' is a Service Description, and refers to the US metric for measuring tires.
Your tires come with a unique code to help you determine what size they are (i.e. P215/65R15). The 'P' is a Service Description, and refers to the US metric for measuring tires.
- P means "passenger car"
- LT stands for "light truck"
- ST is for "special trailer"
- T stands for "temporary" (like a spare tire)
The first number ("215" in our example, P215/65R15 95H) is used for Tire Width. This will vary depending on your model, and the larger the number, the wider the tire.
The second number ("65" in P215/65R15 95H) is the Tire Aspect Ratio. This represents the section height compared to the width as a percentage (65% in this example). A short sidewall can be used for better handling. Bigger numbers are tougher, made for work.
The second letter ("R" in P215/65R15) refers to internal construction. "R" means radial construction, which is used in most cars for better handling. "B" is for bias-ply tires, but this is really only used on heavy-duty trucks.
The third number ("15" in P215/65R15) is the rim diameter, in inches. If you upgrade wheel size, you'll need to pay attention to this number. Otherwise, simply use the same rim diameter as your old tires.
This will be followed by a space, and then another number, referring to the Load Index ("95" in P215/65R15 95H). This is a measurement of how much weight the tire is meant to support. This number is a specific code, which you can locate on a Load-Carrying Capacity Per Tire Chart (remember to multiply by four, for each tire).
Finally, the Letter after this ("H" in P215/65R15 95H) is the speed rating. This is the maximum speed the tire can handle for extended periods.
These include:
- S = 112
- T = 188
- U = 124
- H = 130
- V = 149
- Z = Over 149 (the previous maximum)
- W = 168
- Y = 186
- (Y) = Over 186 (current maximum)
