User Manual

9
SPEED RATING SYSTEM
The speed rating of a
tire indicates the speed
category (or range of
speeds) at which the tire
can carry a load under
specified service conditions.
The speed rating system
used today was developed
in Europe in response to
the need to categorize
tires into standardized
speeds. A letter from A to Z
symbolizes a tire’s certified
speed rating, ranging from
5 km/hr (3 mph) to above
300 km/hr (186 mph). This
rating system (see chart on
this page) describes the top
speed for which a tire is
certified.
When this speed rating
system was originally
developed, the Unlimited
V category of over 210 km/
hr (130 mph) was the top
speed rating a tire could
achieve. As manufacturers
made more tires that fit
into this category, it was necessary to better regulate performance at
standardized speeds to help ensure safety. The Limited V category of
240 km/hr (149 mph) was then created, and the Z or (Y) speed rating was
added as the top speed rating that a tire could achieve. W and Y limited
speed symbols have been added as higher speed categories.
Always consult the tire manufacturer for the maximum speed of Unlimited
Z or (Y) tires. Speed rating is identified as a part of the tire’s sizing or service
description. Exceeding the lawful speed limit is neither recommended nor
endorsed.
In the latest attempt to standardize tire designations, all ratings except
Unlimited Z incorporate the speed symbol and load index as the tire’s
service description.
For Example:
205/60R15 91V
205 = Section Width in Millimeters
60 = Aspect Ratio
R = Radial Construction
15 = Rim Diameter in Inches
91V = Service Description (Load Index and Speed Rating)
Speed
Symbol
Speed
(km/hr)
Speed
(mph)
L
120 75
M
130 81
N
140 87
P
150 94
Q
160 100
R
170 106
S
180 112
T
190 118
U
200 124
H
210 130
V
240 149
W
ZR
270 168
Y
300 186
(Y)
Above 300
Above 186
(consult tire
manufacturer)
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