Understanding lettering on a tire

An optional letter (or letters) indicating the intended use or vehicle class for the tire: P: Passenger Car LT: Light Truck ST: Special Trailer T: Temporary (restricted usage for “space-saver” spare wheels)

3-digit number: The “nominal section width” of the tire in millimeters; the widest point from both outer edges (side wall to side wall). The tire surface that touches the road usually has smaller width. /Slash character for character separation. 2- or 3-digit number: The “aspect ratio” of the sidewall height as a percentage of the nominal section width of the tire. An optional letter indicating the speed rating of the tire. Alternatively, the letter may appear at the end, following the load index. If the letter here is Z, indicating a maximum speed in excess of 240 km/h (149 mph), then a more specific letter W or Y may appear after the load index