Bruno Independent Living Aids
ASL-700 OPERATOR 02-03-2022
15
NHTSA TIRE INFORMATION (continued)
Uniform Tire Quality Grading System (UTQGS)
To help consumers compare a passenger car tire’s treadwear rate, traction performance, and temperature
resistance, the federal government requires tire manufacturers to grade tires in these three areas. This
grading system, known as the Uniform Tire Quality Grading System, provides guidelines for making rela-
tive comparisons when purchasing new tires. You also can use this information to inquire about the quality
of tires placed on new vehicles.
Although this rating system is very helpful when buying new tires, it is not a safety rating or guarantee
of how well a tire will perform or how long it will last. Other factors such as personal driving style, type
of car, quality of the roads, and tire maintenance habits have a significant influence on your tire’s perfor
-
mance and longevity.
Treadwear grades are an indication of a tire’s relative wear rate. The higher the treadwear number is, the
longer it should take for the tread to wear down. For example, a tire grade of 400 should wear twice as
long as a tire grade of 200.
Traction grades are an indication of a tire’s ability to stop on wet pavement. A higher graded tire should
allow you to stop your car on wet roads in a shorter distance than a tire with a lower grade. Traction is
graded from highest to lowest as “AA”, “A”, “B”, and “C”.
Temperature grades are an indication of a tire’s resistance to heat. Sustained high temperature (for exam-
ple, driving long distances in hot weather), can cause a tire to deteriorate, leading to blowouts and tread
separation. From highest to lowest, a tire’s resistance to heat is graded as “A”, “B”, or “C”.
Tire Fundamentals
Federal law requires tire manufacturers to place standardized information on the sidewall of all tires. This
information identifies and describes the fundamental characteristics of the tire and also provides a tire
identification number for safety standard certification and in case of a recall.
Information on Passenger Vehicle Tires
P
The “P” indicates the tire is for passenger vehicles.
Next number
This three-digit number gives the width in millimeters of the tire from sidewall edge to sidewall edge. In
general, the larger the number, the wider the tire.
Next number
This two-digit number, known as the aspect ratio, gives the tire’s ratio of height to width. Numbers of 70
or lower indicate a short sidewall for improved steering response and better overall handling on dry pave-
ment.
R
The “R” stands for radial. Radial ply construction of tires has been the
industry standard for the past 20 years.
Next number
This two-digit number is the wheel or rim diameter in inches. If you
change your wheel size, you will have to purchase new tires to match
the new wheel diameter.
Next number
This two- or three-digit number is the tire’s load index. It is a mea-
surement of how much weight each tire can support. You may find
this information in your owner’s manual. If not, contact a local tire
dealer. Note: You may not find this information on all tires because it
is not required by law.
M+S
The “M+S” or “M/S” indicates that the tire has some mud and snow capability. Most radial tires have these
markings; hence, they have some mud and snow capability.
Speed Rating
The speed rating denotes the speed at which a tire is designed to be driven for extended periods of time.
The ratings range from 99 miles per hour (mph) to 186 mph. These ratings are listed below. Note: You
may not find this information on all tires because it is not required by law.
Letter Rating Speed Rating
DOT HS 809 361
Oct
ober 2001
Q 99 mph
T 118 mph
V 149 mph
R 106 mph
U 124 mph
W 168* mph
S 112 mph
H 130 mph
Y 186* mph
