Uniform Tire Quality Grading System (Utqgs) - Mazda MX-6 Manual

J94S.book Page 12 Saturday, June 23, 2001 1:04 PM
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Uniform Tire Quality Grading System (UTQGS)

Uniform Tire Quality Grading System (UTQGS)
This inform ation relates to the tire grading system developed by the U .S. N ational
H ighw ay Traffic Safety A dm inistration for grading tires by tread wear, traction, and
tem perature perform ance.
▼ Tread Wear
T he tread w ear grade is a com parative rating based on the w ear rate o f the tire w hen tested
under controlled conditions on a specified governm ent test course.
For exam ple, a tire graded 150 w ould w ear o n e-and-a-half tim es as w ell on the governm ent
course as a tire graded 100.
T he relative p erform ance o f tires depends upon the actual conditions o f their use, however,
and m ay depart significantly from the norm because o f variations in driving habits, service
practices and differences in road characteristics and clim ate.
▼ Traction-AA, A, B, C
T he traction grades, from highest to lowest, are AA, A, B, and C. T hese grades represent
the tire 's ability to stop on w et pavem ent as m easured under controlled conditions on
specified governm ent test surfaces o f asphalt and concrete. A tire m arked C m ay have poor
traction perform ance.
The traction g rade assign ed to this tire is based on braking (straight ahead) traction
tests a n d does n o t include acceleration cornering (turning), hydroplaning, or p ea k
traction characteristics.
▼ Temperature-A, B, C
T he tem perature grades are A (the highest), B, and C, represent the tire's resistance to the
generation o f heat and its ability to dissipate heat w hen tested under controlled conditions
on a specified indoor laboratory test wheel.
Sustained high tem perature can cause the m aterial o f the tire to degenerate and reduce tire
life, and excessive tem peratures can lead to sudden tire failure.
G rade C corresponds to a level o f perform ance w hich all passenger vehicle tires m ust m eet
under the Federal M otor Vehicle Safety Standard No. 109. G rades B and A represent
higher levels o f perform ance on the laboratory test w heel than the m inim um required by
law.
9-12
Form No. 8Q50-EA-01G
& WARNING