BMW 328d xDrive Sports Wagon 2014 - Manual (Page 194)

45: aspect ratio in %
R: radial tire code
18: rim diameter in inches
96: load rating, not for ZR tires
Y: speed rating, before the R on ZR tires
Speed letter
Q = up to 100 mph, 160 km/h
R = up to 106 mph, 170 km/h
S = up to 112 mph, 180 km/h
T = up to 118 mph, 190 km/h
H = up to 131 mph, 210 km/h
V = up to 150 mph, 240 km/h
W = up to 167 mph, 270 km/h
Y = up to 186 mph, 300 km/h
Tire Identification Number
DOT code: DOT xxxx xxx 0814
xxxx: manufacturer code for the tire brand
xxx: tire size and tire design
0814: tire age
Tires with DOT codes meet the guidelines of
the U.S. Department of Transportation.
Tire age
DOT … 0814: the tire was manufactured in the
8th week of 2014.
Recommendation
Regardless of wear, replace tires at least every
6 years.
Uniform Tire Quality Grading
Quality grades can be found where applicable
on the tire sidewall between tread shoulder
and maximum section width.
For example: Treadwear 200; Traction AA;
Temperature A
DOT Quality Grades
Treadwear
Traction AA A B C
Temperature A B C
All passenger car tires must conform to Fed‐
eral Safety Requirements in addition to these
grades.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified gov‐
ernment test course. For example, a tire
graded 150 would wear one and one-half, 1 g,
times as well on the government course as a
tire graded 100. The relative performance of
tires depends upon the actual conditions of
their use, however, and may depart signifi‐
cantly from the norm due to variations in driv‐
ing habits, service practices and differences in
road characteristics and climate.
Traction
The traction grades, from highest to lowest,
are AA, A, B, and C.
Those grades represent the tire's ability to
stop on wet pavement as measured under
controlled conditions on specified government
test surfaces of asphalt and concrete. A tire
marked C may have poor traction performance.
The traction grade assigned to this tire is
based on straight-ahead braking traction tests,
and does not include acceleration, cornering,
hydroplaning, or peak traction characteristics.
Temperature
The temperature grades are A, the highest, B,
and C, representing the tire's resistance to the
generation of heat and its ability to dissipate
heat when tested under controlled conditions
on a specified indoor laboratory test wheel.
Sustained high temperature can cause the ma‐
terial of the tire to degenerate and reduce tire
life, and excessive temperature can lead to
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Mobility Wheels and tires
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