Speed Rating and Load Index

When upgrading always choose a tire with equal or higher speed rating and load index.  For example, if a tire is rated 89H, pick a load index of 89 or higher, and a speed rating of H or higher.

Load Index

Load Index Kilograms Load Index Kilograms
71 345 91 615
72 355 92 630
73 365 93 650
74 375 94 670
75 387 95 690
76 400 96 710
77 412 97 730
78 425 98 750
79 437 99 775
80 450 100 800
81 462 101 825
82 475 102 850
83 487 103 875
84 500 104 900
85 515 105 925
86 530 106 950
87 545 107 975
88 560 108 1000
89 580 109 1030
90 600 110 1060

Speed Rating

Speed ratings indicate the maximum speed at which a tire can be run, and they apply only to tires that have not been damaged, overloaded, altered, or  underinflated).  A tire that has been repaired after a puncture is no longer guaranteed to retain the tire manufacturer's original speed rating.

Speed Rating Kilometers Per Hour Miles Per Hour
N 140 87
P 150 93
Q 160 99
R 170 106
S 180 112
T 190 118
U 200 124
H 210 130
V 240 149
Z 240+ 149
W 270 168
Y 300 186

Previously, a V-speed rated tire with the “V” branded “within” the tire size (as in P205/65VR15) indicated that the tire was capable of 210+ km/h.  Today’s new V-speed rated tires are always identified in the tires service description (as in P205/60R15 90V) and this indicates maximum speed of 240 km/h.

SUV and light truck tires have "function ratings" after the brand name.  A/T is All-Terrain,  M/T is max traction mud tire, H/T is Highway all-season tire and S/S is Street Sport tire.

Off-road tires such as this Bridgestone Dueler M/T have deeper grooves compared to ordinary road tires. They give better mud traction in exchange for heat resistance (i.e. lower heat resistance means lower tire life).

Tires, suspension and brakes are integrated systems, so make sure that you take extra precaution and care in maintaining these parts. Not only will they give you less trouble if you do so, but increase your road safety as well.

Temporary spare tires, like the one on the Toyota Echo, aren't a joke. These aren't made to last long so make sure you drive immediately to have your primary tire repaired.

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