#TIRE RACK TIRE COMPARISON CODE#

#TIRE RACK TIRE COMPARISON CODE#

For example, the code '1321' in the figure above means that the tire was produced on the 13 th week of the year 2021. The date of production of a tire is particularly important, and is specified with 2 digits for the week of the year, and 2 digits for the year. Note that tires have many additional marks or codes, such as the DOT code.ĭOT code: the DOT code is a required code in the United States that specifies the company, factory, batch, mold, and date of production of the tire. For example, a tire with a load index of 95 and speed rating of H can carry 1,520 lb (690 kg) at a tire pressure of 42 psi and a speed of 130 mph (210 km/h). The speed rating of a tire is the maximum speed at which a tire can carry a load that corresponds to its load index. Speed rating: The last part of the code is a 1- or 2-digit/letter that indicates the speed rating of the tire. For example, a load index of 95 means that a tire can carry 1,520 lb (690 kg) at a tire pressure of 42 psi. The load index indicates the maximum weight that a tire can carry at a given inflation level. Load index: The next part of the code is a 2- or 3-digit number referred to as the load index of the tire. There are many different tire sizes, and the same wheel (rim) can be used with different tire sizes, as long as the middle of the tire is the correct size for the rim. Cross-ply tires are tires whose internal construction is made of nylon cord placed diagonally across each other, usually at an angle of 55°.ĭiameter of the wheel: The next part of the code is a 1- or 2-digit number that indicates the diameter of the wheel, in units of inches, that the tire is designed to fit.This offers additional support and makes the tire stiffer. This additional layer is comprised of stabilizer belts, typically made of steel or other corded material applied at different angles relative to the topmost layer of ply. This type of tire is similar in construction to diagonal tires except that a bias-belted tire has an additional layer above the topmost layer of ply. In this type of tire construction, the cords run along the circumference of the tire at a 30-40° angle from bead (the part of the tire that contacts the rim of the wheel) to bead, and the layers crisscross over each other. In a radial internal construction, the cords run along the circumference of the tire, perpendicular to the direction of travel (or axis of rotation). Almost all passenger cars use tires with radial internal construction. It is an optional letter in the tire code, and if it is omitted, it is assumed that the tire is a cross-ply tire. The internal construction is largely responsible for the strength and durability of a tire. The inside of a tire is made up of plies of cord, referred to as the tire's carcass. Internal construction: The next part of the code is a single letter (B, D, R) that indicates the internal construction of the tire. For example, for a tire with code 200/65, the section height is 200 × 65% = 130 mm. A tire with the code xxx/65 indicates that the section height of the tire is 65% of its width. The section height is the height of the tire measured from the rim to the outer edge of the tire the section width is the width from sidewall to sidewall. It is a 2- or 3-digit number that indicates the ratio of the tire's section height to its width. In the figure above, the 215 means that the nominal section width of the tire is 215 mm.Īspect ratio: The next part of the code follows the forward slash ( / ). The nominal section width is the widest point of the tire or the width from sidewall to sidewall. Nominal section width: The second part of the code is a 3-digit number that describes the nominal section width of the tire in millimeters (mm). Tires with the T specification are usually spare tires that are not intended for everyday use. These types of tires are used for trailers such as boat trailers, utility trailers, and travel trailers. Tires with the LT specification are designed to carry heavy loads and are capable of towing trailers. Tires with the P specification are intended for use with cars, SUVs, crossovers, minivans, and smaller pickup trucks. Intended use: The first part of the code is made up of 1 or 2 letters (P, LT, ST, T) that describe the type of vehicle that the tire is intended to be used with. Each part of the code describes some characteristic of the tire refer to the figure below. Being able to read the tire code can be important, particularly when considering getting new wheels or tires, as being able to read the tire code is necessary for calculating things like tire size. Tire 1: / RĬar tires are described by an alphanumeric code, as shown in the figure below. Use this calculator to compare the sizes of two tires both numerically and visually.

Tire rack tire comparison