On modern tires, a service description code is appended to the tire code. (For example "87H" in the code P195/60R15 87H)
The two digit number indicates the load capacity of the tire. The number of load pounds for the tire is found in this chart:|
INDEX
|
LBS.
|
INDEX
|
LBS.
|
INDEX
|
LBS.
|
INDEX
|
LBS.
|
|
71
|
761
|
81
|
1019
|
91
|
1356
|
101
|
1819
|
|
72
|
783
|
82
|
1047
|
92
|
1389
|
102
|
1874
|
|
73
|
806
|
83
|
1074
|
93
|
1433
|
103
|
1929
|
|
74
|
827
|
84
|
1102
|
94
|
1477
|
104
|
1984
|
|
75
|
853
|
85
|
1135
|
95
|
1521
|
105
|
2039
|
|
76
|
882
|
86
|
1168
|
96
|
1565
|
106
|
2094
|
|
77
|
908
|
87
|
1201
|
97
|
1609
|
107
|
2149
|
|
78
|
937
|
88
|
1235
|
98
|
1653
|
108
|
2205
|
|
79
|
963
|
89
|
1279
|
99
|
1709
|
109
|
2271
|
|
80
|
992
|
90
|
1323
|
100
|
1764
|
110
|
2337
|
The letter in "87H" indicates the speed rating of the tire.
Speed ratings evolved in Europe where some highways do not have speed limits. The "Z" rating that is often shown within the tire code (see ZR above) was believed to be an adequate highest rating when implemented some years ago. When "Z" speed rated tires were developed, testing did not exceed 149 m.p.h. (or at least results of any tests were not integrated into the coding of the tires.) The abilities of "Z" tires may be higher but are unknown. Since the introduction of that code, tires have been rated at higher limits resulting in "V" code indicating a MAXIMUM tested rate of 149m.p.h, plus "W" and "Y" codes indicating testing to a maximum of 168 and 186 m.p.h respectively. Consult the owners manual and follow vehicle manufacturers specifications whenever replacing tires. When a vehicle may exceed usual posted speed limits consult the tire manufacturer for racing and high speed specifications. If a vehicle is modified for racing or high speed consult a qualified engineer and tire manufacturer to ensure tire specifications are suitable for the application. In summary, don't bet your life on interpretation of a coded number on a tire. Talk to tire experts and use tires that meet or exceeds the demands of use. Speed ratings in miles per hour are found in this chart:
|
SYMBOL
|
M.P.H.
|
SYMBOL
|
M.P.H.
|
|
M
|
81
|
U
|
124
|
|
N
|
87
|
H
|
130
|
|
P
|
93
|
V
|
149
|
|
Q
|
99
|
W
|
168
|
|
R
|
106
|
Y
|
186
|
|
S
|
112
|
Z
|
149
|
|
T
|
118
|
|
|