UNIFORM TYRE QUALITY GRADING
The Uniform Tyre Quality Grading System, or UTQG, is a system developed by the U.S. government designed to provide consumers with information on tyre treadwear, traction, and operating temperature resistance.
TREADWEAR RATING
The treadwear grade is a comparative numerical rating based on the wear rate of the tyre when tested under controlled conditions on a specified government test course. For example, a tyre graded 200 would wear two times as well on the course as a tyre graded 100. The relative performance of a tyre depends upon the actual conditions of its use which may depart significantly from the test conditions due to variations in driving habits, service practices, and differences in road characteristics and climates.
TRACTION RATING
The UTQG Traction Rating indicates the tyre's ability to stop a vehicle moving straight forward on wet pavement. The ratings are AA, A, B, and C, with AA being the best.
TEMPERATURE RATING
The UTQG Temperature Rating indicates the tyre's ability to effectively dissipate heat. The ratings range from A to C, with A being the best.
*(UTQG treadwear goes in 20 point increments)
AIR PRESSURE
With the right amount of air pressure, your tyres will perform better, wear longer and save fuel. The "right amount" of air pressure for the original equipment or same size tyres is specified by the vehicle manufacturer and may be different for front and rear tyres. Check with your Nitto dealer if the replacement tyres on your vehicle are no longer the same size as the O.E. tyres.
U.S. DOT STANDARD SAFETY CODE
The letters "DOT" certify compliance with all safety standards established by the U.S. Department of Transportation (DOT). This is followed by a combination of up to 12 numbers and letters.
The first two numbers or letters are the plant code where the tyre was manufactured, and the last three to four numbers represent the week and year the tyre was built.
Tyres built in the 1990's will have three numbers and may have a triangle to note the decade. Examples are below.
Note: Recently it became mandatory to apply a partial DOT serial number on the sidewall opposite the complete DOT serial number. The partial DOT serial does not show the week and year that the tyre was manufactured, but may still assist consumers in identifying tyres should a recall be necessary. The purpose in applying the partial DOT serial number was to facilitate tyre identification when the full DOT serial number may have been mounted towards the inboard side of the vehicle, and consequently not visible unless the vehicle was put on a lift for inspection.
AIR PRESSURE
With the right amount of air pressure, your tyres will perform better, wear longer and save fuel. The "right amount" of air pressure for the original equipment or same size tyres is specified by the vehicle manufacturer and may be different for front and rear tyres. Check with your Nitto dealer if the replacement tyres on your vehicle are no longer the same size as the O.E. tyres.
TYRE SIZE, LOAD INDEX, AND SPEED SYMBOL
The sidewall of a tyre includes a variety of important information. The numbers and letters identify dimensions and performance standards that allow you to compare tyres more accurately and efficiently. This diagram will help you to understand those numbers and letters. For assistance in selecting a replacement tyre, always consult your Nitto Tyre dealer.
Section Width
The width of a tyre is referred to as its section width. This is the width of an inflated tyre in millimetres at its widest point from sidewall to sidewall.
Section Height
The section height of the tyre is measured in millimetres also. The section height is approximately the distance from the rim to the tread surface of the tyre when it is not carrying any weight.
Aspect Ratio
The aspect ratio is the dimensional relationship of the section height to the section width. The lower the aspect ratio, the shorter the sidewall and the wider the shoulder-to-shoulder width.
Radial
The "R" stands for "radial," indicating the tyre has radial construction.
This One is Easy!
The "20" indicates the diameter of the wheel in inches. You can learn more about changing the diameter of the wheels of your car in the Plus Sizing section.
Load Index
The load index number and speed symbol correspond to the maximum load-carrying capacity of the tyre and its maximum speed capability.
The load index is an assigned number that corresponds with the load-carrying capacity of the tyre. For example, "96" indicates a load-carrying capacity of 710kg at maximum inflation pressure. The load index for most passenger car tyres ranges from 75-100. Click here to view the complete load inflation index.
Speed Symbol
Speed ratings are determined by indoor laboratory testing methods, which measure high-speed tyre durability under controlled test conditions. These test procedures do not take into account underinflation, tyre damage, vehicle characteristics or road conditions which can lead to sudden tyre failure or loss of vehicle control at much lower speeds than indicated by the tyre's speed rating.
Light Truck Tyres
The "LT" designation stands for "Light Truck." These tyres are intended for more severe use often seen on trucks and follow load and inflation standards established by the Tyre and Rim Association (TRA). Load Index values and load capacities for these tyres can be found in TRA manuals.
ABOUT AIR PRESSURE
With the right amount of air pressure, your tyres will perform better, wear longer and save fuel. The "right amount" of air pressure for the original equipment or same size tyres is specified by the vehicle manufacturer and may be different for front and rear tyres. Check with your Nitto dealer if the replacement tyres on your vehicle are no longer the same size as the O.E. tyres.
MUD AND SNOW DESIGNATION
The "M+S" indicates the tyre is an “all season tyre”. “M+S” is an abbreviation of “Mud & Snow”.. The Mud and Snow designation may also appear as "M&S" or "M/S." This designation is popular in U.S. markets where road conditions vary greatly between seasons and snow covered roads are common.
