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Tire Sizing

Before you can determine the replacement tire that best fits your lifestyle, you must first find the tire that properly fits your vehicle. Identifying the proper replacement tire size is more than merely measuring the radius. It considers factors such as aspect ratio, load index, speed rating, metric type and more. 

By using our TireTracker, you can easily find what fits you.* Simply enter your vehicle information and follow our lead. We’ll show you the Hercules tires that are right for your vehicle.*

If you prefer to do a little math to find your tire size, you can use the following calculations:

Example: Size 275/55R20

  1. 275 (mm) / 25.4 = 10.8 inches
  2. 10.8 x .55 = 5.94
  3. (5.94 x 2) + 20 = 31.88 inches

Section Width x 25.4 = SWi (converts mm to inches)

SWi x Aspect Ratio = Section Height (SH)

(SH x 2) + Rim Diameter Outside Diameter

Load Index Table

198417085.5

LI kg LBS LI kg LBS LI kg LBS LI kg LBS
0 45  99.2 70 335  738.5 140 2500 5511.5 210  19000 41887.1
1 46.2  101.9 71 345  760.6 141 2575 5676.8 211 19500 42989.4
2 47.5  104.7 72 355  782.6 142 2650  5842.2 212 20000  44091.7
3 48.7  107.4 73 365  804.7 143 2725  6007.5 213 20600  45414.5
4 50  110.2 74 375  826.7 144 2800  6172.8 214 21200  46737.2
5 51.5  113.5 75 387  853.2 145 2900  6393.3 215 21800  48060.0
6 53  116.8 76 400  881.8 146 3000  6613.8 216 22400  49382.7
7 54.5  120.1 77 412  908.3 147 3075  6779.1 217 23000  50705.5
8 56  123.5 78 425  936.9 148 3150  6944.4 218 23600  52028.2
9 58  127.9 79 437  963.4 149 3250  7164.9 219 24300  53571.4
10 60  132.3 80 450  992.1 150 3350  7385.4 220 25000  55114.6
11 51.5  113.5 81 462  1018.5 151 3450  7605.8 221 25750  56768.1
12 63  138.9 82 475  1047.2 152 3550  7826.3 222 26500  58421.5
13 65  143.3 83 487  1073.6 153 3650  8046.7 223 27250  60075.0
14 67  147.7 84 500  1102.3 154 3750  8267.2 224 28000  61728.4
15 69  152.1 85 515  1135.4 155 3875  8542.8 225 29000  63933.0
16 71  156.5 86 530  1168.4 156 4000  8818.3 226 30000  66137.6
17 73  160.9 87 545  1201.5 157 4125  9093.9 227 30750  67791.0
18 75  165.3 88 560  1234.6 158 4250  9369.5 228 31500  69444.4
19 77.5  170.9 89 580  1278.7 159 4375  9645.1 229 32500  71649.0
20 80  176.4 90 600  1322.8 160 4500  9920.6 230 33500  73853.6
21 82.5  181.9 91 615  1355.8 161 4625  10196.2 231 34500  76058.2
22 85  187.4 92 630  1388.9 162 4750  10471.8 232 35500 78262.8
23 87.5  192.9 93 650  1433.0 163 4875  10747.4 233 36500 80467.4
24 90  198.4 94 670  1477.1 164 5000  11022.9 234  37500 82672.0
25 92.5  203.9 95 690  1521.2 165 5150  11353.6 235 38750  85427.7
26 95 209.4 96 710  1565.3 166 5300  11684.3 236 40000  88183.4
27 97.5 214.9 97 730  1609.3 167 5450  12015.0 237 41250  90939.2
28 100 220.5 98 750  1653.4 168 5600  12345.7 238 42500  93694.9
29 103 227.1 99 775  1708.6 169 5800  12786.6 239 43750  96450.6
30 106 233.7 100 800  1763.7 170 6000  13227.5 240 45000  99206.3
31 109 240.3 101 825  1818.8 171 6150  13558.2 241 46250  101962.1
32 112 246.9 102 850  1873.9 172 6300  13888.9 242 47500  104717.8
33 115 253.5 103 875  1929.0 173 6500  14329.8 243 48750  107473.5
34 118 260.1 104 900  1984.1 174 6700  14770.7 244 50000  110229.3
35 121 266.8 105 925  2039.2 175 6900  15211.6 245 51500  113536.2
36 125 275.6 106 950  2094.4 176 7100  15652.6 246 53000  116843.0
37 128 282.2 107 975  2149.5 177 7300  16093.5 247 54500  120149.9
38 132 291.0 108 1000  2204.6 178 7500  16534.4 248 56000  123456.8
39 136  299.8 109 1030  2270.7 179 7750  17085.5 249 58000  127866.0
40 140 308.6 110 1060  2336.9 180 8000  17636.7 250 60000  132275.1
41 145 319.7 111 1090  2403.0 181 8250 18187.8 251 61500  135582.0
42 150 330.7 112 1120  2469.1 182 8500  18739.0 252 63000  138888.9
43 155 341.7 113 1150  2535.3 183 8750  19290.1 253 65000  143298.1
44 160 352.7 114 1180  2601.4 184 9000  19841.3 254 67000  147707.2
45 165 363.8 115 1215  2678.6 185 9250  20392.4 255 69000  152116.4
160 170 374.8 116 1250  2755.7 186 9500  20943.6 256 71000  156525.6
47 175  385.8 117 1285  2832.9 187 9750  21494.7 257 73000  160934.7
48 180 396.8 118 1320  2910.1 188 10000  22045.9 258 75000  165343.9
49 185 407.8 119 1360  2998.2 189 10300  22707.2 259 77500  170855.4
50 190 418.9 120 1400  3086.4 190 10600  23368.6 260 80000  176366.8
51 195 429.9 121 1450  3196.6 191 10900  24030.0 261 82500  181878.3
52 200 440.9 122 1500  3306.9 192 11200  24691.4 262 85000  187389.8
53 206 454.1 123 1550  3417.1 193 11500  25352.7 263 87500  192901.2
54 212 467.4 124 1600  3527.3 194 11800  26014.1 264 90000  198412.7
55 218 480.6 125 1650  3637.6 195 12150  26785.7 265 92500  203924.2
56 224 493.8 126 1700  3747.8 196 12500  27557.3 266 95000  209435.6
57 230 507.1 127 1750  3858.0 197 12850  28328.9 267 97500  215947.1
58 236 520.3 128 1800  3968.3 198 13200  29100.5 268 10000  220458.6
59 243 535.7 129 1850  4078.5 199 13600  29982.4 269 103000  227072.3
60 250 551.1 130 1900  4188.7 200 14000  30864.2 270 106000  233686.1
61 257 566.6 131 1950  4298.9 201 14500  31966.5 271 109000  240299.8
62 265  584.2 132 2000  4409.2 202 15000  33068.8 272 112000  246913.6
63 272 599.6 133 2060  4541.4 203 15500  34171.1 273 115000 253527.3
64 280 617.3 134 2120  4673.7 204 16000  35273.4 274 118000  260141.1
65 290 639.3 135 2180 4806.0 205 16500  36375.7 275 121000  266754.9
66 300 661.4 136 2240  4938.3 206 17000  37478.0 276 125000  275573.2
67 307 676.8 137 2300  5070.5 207 17500  38580.2 277 128500  283289.2
68 315 694.4 138 2360  5202.8 208 18000  39682.5 278 132000  291005.3
69 325 716.5 139 2430  5357.1 209 18500  40784.8 279 136000  299823.6

 

Speed Ratings Symbols

SPEED SYMBOL MAXIMUM SPEED (km/h) MAXIMUM SPEED (mph)
A1  3
A2  10  6
A3  15  9
A4  20  12
A5  25  16
A6  30  19
A7  35  22
A8  40  25
50  31
C 60  37
65  40
70  43
80  50
90  56
100 62
110  68
120  75
130  81
N 140  87
150  94
160  100
170  106
180  112
190  118
200  124
210  130
240  149
270  169
Y 300  186
ZR  OVER 240  OVER 149

 

 *Fitment Guide Terms of Use: This tire sizing tool, the website and all contents thereof and all services are provided on an "as is" basis without any warranty or condition, express, implied or statutory. We specifically disclaim any implied warranties of title, merchantability, fitness for a particular purpose and non-infringement. We do not warrant or guarantee that the contents of the website or the information provided by the tire sizing tools will be accurate, up-to-date or otherwise reliable.

In no event shall we be liable for lost profits or any special, incidental, indirect, consequential or reliance damages arising out of or in connection with this sizing tool or our services, under any legal theory, even if we have been advised of the possibility of such damages and notwithstanding the failure of essential purposes of any limited remedy.