| Code | Difference | = 50mph | 1000miles = | Diameter | Wall,in | Wall,mm |
|---|---|---|---|---|---|---|
| 285/55-18 | 0.00 % | 50.00 | 1,000.00 | 30.34 | 6.17 | 156.75 |
| 185/85-18 | +0.13 % | 50.06 | 998.70 | 30.38 | 6.19 | 157.25 |
| 195/80-18 | -0.19 % | 49.90 | 1,001.95 | 30.28 | 6.14 | 156.00 |
| 315/50-18 | +0.19 % | 50.10 | 998.05 | 30.40 | 6.20 | 157.50 |
| 225/70-18 | +0.19 % | 50.10 | 998.05 | 30.40 | 6.20 | 157.50 |
| 265/60-18 | +0.58 % | 50.29 | 994.16 | 30.52 | 6.26 | 159.00 |
| 245/65-18 | +0.65 % | 50.32 | 993.51 | 30.54 | 6.27 | 159.25 |
| 205/75-18 | -0.78 % | 49.61 | 1,007.79 | 30.11 | 6.05 | 153.75 |
| 255/60-18 | -0.97 % | 49.51 | 1,009.73 | 30.05 | 6.02 | 153.00 |
| 235/65-18 | -1.04 % | 49.48 | 1,010.38 | 30.03 | 6.01 | 152.75 |
| 305/50-18 | -1.10 % | 49.45 | 1,011.03 | 30.01 | 6.00 | 152.50 |
| 215/75-18 | +1.17 % | 50.58 | 988.32 | 30.70 | 6.35 | 161.25 |
| 275/55-18 | -1.43 % | 49.29 | 1,014.27 | 29.91 | 5.95 | 151.25 |
| 295/55-18 | +1.43 % | 50.71 | 985.73 | 30.78 | 6.39 | 162.25 |
| 325/50-18 | +1.49 % | 50.75 | 985.08 | 30.80 | 6.40 | 162.50 |
| 335/45-18 | -1.56 % | 49.22 | 1,015.57 | 29.87 | 5.94 | 150.75 |
| 215/70-18 | -1.62 % | 49.19 | 1,016.22 | 29.85 | 5.93 | 150.50 |
| 205/80-18 | +1.88 % | 50.94 | 981.19 | 30.91 | 6.46 | 164.00 |
| Ratio: | 25 | 30 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | 75 | 80 | 85 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Wheel Size 12
|
|||||||||||||
|
Wheel Size 13
|
|||||||||||||
|
Wheel Size 14
|
|||||||||||||
|
Wheel Size 15
|
|||||||||||||
|
Wheel Size 16
|
|||||||||||||
|
Wheel Size 16.5
|
|||||||||||||
|
Wheel Size 17
|
|||||||||||||
|
Wheel Size 18
|
|||||||||||||
| 145 |
145/25-18
d=20.85
w=1.43
-31.27%
|
145/30-18
d=21.43
w=1.71
-29.39%
|
145/35-18
d=22.00
w=2.00
-27.51%
|
145/40-18
d=22.57
w=2.28
-25.63%
|
145/45-18
d=23.14
w=2.57
-23.74%
|
145/50-18
d=23.71
w=2.85
-21.86%
|
145/55-18
d=24.28
w=3.14
-19.98%
|
145/60-18
d=24.85
w=3.43
-18.10%
|
145/65-18
d=25.42
w=3.71
-16.22%
|
145/70-18
d=25.99
w=4.00
-14.34%
|
145/75-18
d=26.56
w=4.28
-12.46%
|
145/80-18
d=27.13
w=4.57
-10.57%
|
145/85-18
d=27.70
w=4.85
-8.69%
|
| 155 |
155/25-18
d=21.05
w=1.53
-30.62%
|
155/30-18
d=21.66
w=1.83
-28.61%
|
155/35-18
d=22.27
w=2.14
-26.60%
|
155/40-18
d=22.88
w=2.44
-24.59%
|
155/45-18
d=23.49
w=2.75
-22.58%
|
155/50-18
d=24.10
w=3.05
-20.57%
|
155/55-18
d=24.71
w=3.36
-18.55%
|
155/60-18
d=25.32
w=3.66
-16.54%
|
155/65-18
d=25.93
w=3.97
-14.53%
|
155/70-18
d=26.54
w=4.27
-12.52%
|
155/75-18
d=27.15
w=4.58
-10.51%
|
155/80-18
d=27.76
w=4.88
-8.50%
|
155/85-18
d=28.37
w=5.19
-6.49%
|
| 165 |
165/25-18
d=21.25
w=1.62
-29.97%
|
165/30-18
d=21.90
w=1.95
-27.83%
|
165/35-18
d=22.55
w=2.27
-25.69%
|
165/40-18
d=23.20
w=2.60
-23.55%
|
165/45-18
d=23.85
w=2.92
-21.41%
|
165/50-18
d=24.50
w=3.25
-19.27%
|
165/55-18
d=25.15
w=3.57
-17.13%
|
165/60-18
d=25.80
w=3.90
-14.99%
|
165/65-18
d=26.44
w=4.22
-12.85%
|
165/70-18
d=27.09
w=4.55
-10.70%
|
165/75-18
d=27.74
w=4.87
-8.56%
|
165/80-18
d=28.39
w=5.20
-6.42%
|
165/85-18
d=29.04
w=5.52
-4.28%
|
| 175 |
175/25-18
d=21.44
w=1.72
-29.32%
|
175/30-18
d=22.13
w=2.07
-27.05%
|
175/35-18
d=22.82
w=2.41
-24.78%
|
175/40-18
d=23.51
w=2.76
-22.51%
|
175/45-18
d=24.20
w=3.10
-20.24%
|
175/50-18
d=24.89
w=3.44
-17.97%
|
175/55-18
d=25.58
w=3.79
-15.70%
|
175/60-18
d=26.27
w=4.13
-13.43%
|
175/65-18
d=26.96
w=4.48
-11.16%
|
175/70-18
d=27.65
w=4.82
-8.89%
|
175/75-18
d=28.33
w=5.17
-6.62%
|
175/80-18
d=29.02
w=5.51
-4.35%
|
175/85-18
d=29.71
w=5.86
-2.08%
|
| 185 |
185/25-18
d=21.64
w=1.82
-28.68%
|
185/30-18
d=22.37
w=2.19
-26.27%
|
185/35-18
d=23.10
w=2.55
-23.87%
|
185/40-18
d=23.83
w=2.91
-21.47%
|
185/45-18
d=24.56
w=3.28
-19.07%
|
185/50-18
d=25.28
w=3.64
-16.67%
|
185/55-18
d=26.01
w=4.01
-14.27%
|
185/60-18
d=26.74
w=4.37
-11.87%
|
185/65-18
d=27.47
w=4.73
-9.47%
|
185/70-18
d=28.20
w=5.10
-7.07%
|
185/75-18
d=28.93
w=5.46
-4.67%
|
185/80-18
d=29.65
w=5.83
-2.27%
|
185/85-18
d=30.38
w=6.19
+0.13%
|
| 195 |
195/25-18
d=21.84
w=1.92
-28.03%
|
195/30-18
d=22.61
w=2.30
-25.50%
|
195/35-18
d=23.37
w=2.69
-22.97%
|
195/40-18
d=24.14
w=3.07
-20.44%
|
195/45-18
d=24.91
w=3.45
-17.91%
|
195/50-18
d=25.68
w=3.84
-15.38%
|
195/55-18
d=26.44
w=4.22
-12.85%
|
195/60-18
d=27.21
w=4.61
-10.32%
|
195/65-18
d=27.98
w=4.99
-7.79%
|
195/70-18
d=28.75
w=5.37
-5.25%
|
195/75-18
d=29.52
w=5.76
-2.72%
|
195/80-18
d=30.28
w=6.14
-0.19%
|
195/85-18
d=31.05
w=6.53
+2.34%
|
| 205 |
205/25-18
d=22.04
w=2.02
-27.38%
|
205/30-18
d=22.84
w=2.42
-24.72%
|
205/35-18
d=23.65
w=2.82
-22.06%
|
205/40-18
d=24.46
w=3.23
-19.40%
|
205/45-18
d=25.26
w=3.63
-16.74%
|
205/50-18
d=26.07
w=4.04
-14.08%
|
205/55-18
d=26.88
w=4.44
-11.42%
|
205/60-18
d=27.69
w=4.84
-8.76%
|
205/65-18
d=28.49
w=5.25
-6.10%
|
205/70-18
d=29.30
w=5.65
-3.44%
|
205/75-18
d=30.11
w=6.05
-0.78%
|
205/80-18
d=30.91
w=6.46
+1.88%
|
205/85-18
d=31.72
w=6.86
+4.54%
|
| 215 |
215/25-18
d=22.23
w=2.12
-26.73%
|
215/30-18
d=23.08
w=2.54
-23.94%
|
215/35-18
d=23.93
w=2.96
-21.15%
|
215/40-18
d=24.77
w=3.39
-18.36%
|
215/45-18
d=25.62
w=3.81
-15.57%
|
215/50-18
d=26.46
w=4.23
-12.78%
|
215/55-18
d=27.31
w=4.66
-9.99%
|
215/60-18
d=28.16
w=5.08
-7.20%
|
215/65-18
d=29.00
w=5.50
-4.41%
|
215/70-18
d=29.85
w=5.93
-1.62%
|
215/75-18
d=30.70
w=6.35
+1.17%
|
215/80-18
d=31.54
w=6.77
+3.96%
|
215/85-18
d=32.39
w=7.19
+6.75%
|
| 225 |
225/25-18
d=22.43
w=2.21
-26.08%
|
225/30-18
d=23.31
w=2.66
-23.16%
|
225/35-18
d=24.20
w=3.10
-20.24%
|
225/40-18
d=25.09
w=3.54
-17.32%
|
225/45-18
d=25.97
w=3.99
-14.40%
|
225/50-18
d=26.86
w=4.43
-11.48%
|
225/55-18
d=27.74
w=4.87
-8.56%
|
225/60-18
d=28.63
w=5.31
-5.64%
|
225/65-18
d=29.52
w=5.76
-2.72%
|
225/70-18
d=30.40
w=6.20
+0.19%
|
225/75-18
d=31.29
w=6.64
+3.11%
|
225/80-18
d=32.17
w=7.09
+6.03%
|
225/85-18
d=33.06
w=7.53
+8.95%
|
| 235 |
235/25-18
d=22.63
w=2.31
-25.43%
|
235/30-18
d=23.55
w=2.78
-22.38%
|
235/35-18
d=24.48
w=3.24
-19.33%
|
235/40-18
d=25.40
w=3.70
-16.28%
|
235/45-18
d=26.33
w=4.16
-13.23%
|
235/50-18
d=27.25
w=4.63
-10.19%
|
235/55-18
d=28.18
w=5.09
-7.14%
|
235/60-18
d=29.10
w=5.55
-4.09%
|
235/65-18
d=30.03
w=6.01
-1.04%
|
235/70-18
d=30.95
w=6.48
+2.01%
|
235/75-18
d=31.88
w=6.94
+5.06%
|
235/80-18
d=32.80
w=7.40
+8.11%
|
235/85-18
d=33.73
w=7.86
+11.16%
|
| 245 |
245/25-18
d=22.82
w=2.41
-24.78%
|
245/30-18
d=23.79
w=2.89
-21.60%
|
245/35-18
d=24.75
w=3.38
-18.42%
|
245/40-18
d=25.72
w=3.86
-15.25%
|
245/45-18
d=26.68
w=4.34
-12.07%
|
245/50-18
d=27.65
w=4.82
-8.89%
|
245/55-18
d=28.61
w=5.31
-5.71%
|
245/60-18
d=29.57
w=5.79
-2.53%
|
245/65-18
d=30.54
w=6.27
+0.65%
|
245/70-18
d=31.50
w=6.75
+3.83%
|
245/75-18
d=32.47
w=7.23
+7.01%
|
245/80-18
d=33.43
w=7.72
+10.19%
|
245/85-18
d=34.40
w=8.20
+13.36%
|
| 255 |
255/25-18
d=23.02
w=2.51
-24.13%
|
255/30-18
d=24.02
w=3.01
-20.83%
|
255/35-18
d=25.03
w=3.51
-17.52%
|
255/40-18
d=26.03
w=4.02
-14.21%
|
255/45-18
d=27.04
w=4.52
-10.90%
|
255/50-18
d=28.04
w=5.02
-7.59%
|
255/55-18
d=29.04
w=5.52
-4.28%
|
255/60-18
d=30.05
w=6.02
-0.97%
|
255/65-18
d=31.05
w=6.53
+2.34%
|
255/70-18
d=32.06
w=7.03
+5.64%
|
255/75-18
d=33.06
w=7.53
+8.95%
|
255/80-18
d=34.06
w=8.03
+12.26%
|
255/85-18
d=35.07
w=8.53
+15.57%
|
| 265 |
265/25-18
d=23.22
w=2.61
-23.49%
|
265/30-18
d=24.26
w=3.13
-20.05%
|
265/35-18
d=25.30
w=3.65
-16.61%
|
265/40-18
d=26.35
w=4.17
-13.17%
|
265/45-18
d=27.39
w=4.69
-9.73%
|
265/50-18
d=28.43
w=5.22
-6.29%
|
265/55-18
d=29.48
w=5.74
-2.85%
|
265/60-18
d=30.52
w=6.26
+0.58%
|
265/65-18
d=31.56
w=6.78
+4.02%
|
265/70-18
d=32.61
w=7.30
+7.46%
|
265/75-18
d=33.65
w=7.82
+10.90%
|
265/80-18
d=34.69
w=8.35
+14.34%
|
265/85-18
d=35.74
w=8.87
+17.78%
|
| 275 |
275/25-18
d=23.41
w=2.71
-22.84%
|
275/30-18
d=24.50
w=3.25
-19.27%
|
275/35-18
d=25.58
w=3.79
-15.70%
|
275/40-18
d=26.66
w=4.33
-12.13%
|
275/45-18
d=27.74
w=4.87
-8.56%
|
275/50-18
d=28.83
w=5.41
-5.00%
|
275/55-18
d=29.91
w=5.95
-1.43%
|
275/60-18
d=30.99
w=6.50
+2.14%
|
275/65-18
d=32.07
w=7.04
+5.71%
|
275/70-18
d=33.16
w=7.58
+9.28%
|
275/75-18
d=34.24
w=8.12
+12.85%
|
275/80-18
d=35.32
w=8.66
+16.41%
|
275/85-18
d=36.41
w=9.20
+19.98%
|
| 285 |
285/25-18
d=23.61
w=2.81
-22.19%
|
285/30-18
d=24.73
w=3.37
-18.49%
|
285/35-18
d=25.85
w=3.93
-14.79%
|
285/40-18
d=26.98
w=4.49
-11.09%
|
285/45-18
d=28.10
w=5.05
-7.40%
|
285/50-18
d=29.22
w=5.61
-3.70%
|
285/55-18
d=30.34
w=6.17
0.00%
|
285/60-18
d=31.46
w=6.73
+3.70%
|
285/65-18
d=32.59
w=7.29
+7.40%
|
285/70-18
d=33.71
w=7.85
+11.09%
|
285/75-18
d=34.83
w=8.42
+14.79%
|
285/80-18
d=35.95
w=8.98
+18.49%
|
285/85-18
d=37.07
w=9.54
+22.19%
|
| 295 |
295/25-18
d=23.81
w=2.90
-21.54%
|
295/30-18
d=24.97
w=3.48
-17.71%
|
295/35-18
d=26.13
w=4.06
-13.88%
|
295/40-18
d=27.29
w=4.65
-10.06%
|
295/45-18
d=28.45
w=5.23
-6.23%
|
295/50-18
d=29.61
w=5.81
-2.40%
|
295/55-18
d=30.78
w=6.39
+1.43%
|
295/60-18
d=31.94
w=6.97
+5.25%
|
295/65-18
d=33.10
w=7.55
+9.08%
|
295/70-18
d=34.26
w=8.13
+12.91%
|
295/75-18
d=35.42
w=8.71
+16.74%
|
295/80-18
d=36.58
w=9.29
+20.57%
|
295/85-18
d=37.74
w=9.87
+24.39%
|
| 305 |
305/25-18
d=24.00
w=3.00
-20.89%
|
305/30-18
d=25.20
w=3.60
-16.93%
|
305/35-18
d=26.41
w=4.20
-12.98%
|
305/40-18
d=27.61
w=4.80
-9.02%
|
305/45-18
d=28.81
w=5.40
-5.06%
|
305/50-18
d=30.01
w=6.00
-1.10%
|
305/55-18
d=31.21
w=6.60
+2.85%
|
305/60-18
d=32.41
w=7.20
+6.81%
|
305/65-18
d=33.61
w=7.81
+10.77%
|
305/70-18
d=34.81
w=8.41
+14.73%
|
305/75-18
d=36.01
w=9.01
+18.68%
|
305/80-18
d=37.21
w=9.61
+22.64%
|
305/85-18
d=38.41
w=10.21
+26.60%
|
| 315 |
315/25-18
d=24.20
w=3.10
-20.24%
|
315/30-18
d=25.44
w=3.72
-16.15%
|
315/35-18
d=26.68
w=4.34
-12.07%
|
315/40-18
d=27.92
w=4.96
-7.98%
|
315/45-18
d=29.16
w=5.58
-3.89%
|
315/50-18
d=30.40
w=6.20
+0.19%
|
315/55-18
d=31.64
w=6.82
+4.28%
|
315/60-18
d=32.88
w=7.44
+8.37%
|
315/65-18
d=34.12
w=8.06
+12.46%
|
315/70-18
d=35.36
w=8.68
+16.54%
|
315/75-18
d=36.60
w=9.30
+20.63%
|
315/80-18
d=37.84
w=9.92
+24.72%
|
315/85-18
d=39.08
w=10.54
+28.80%
|
| 325 |
325/25-18
d=24.40
w=3.20
-19.59%
|
325/30-18
d=25.68
w=3.84
-15.38%
|
325/35-18
d=26.96
w=4.48
-11.16%
|
325/40-18
d=28.24
w=5.12
-6.94%
|
325/45-18
d=29.52
w=5.76
-2.72%
|
325/50-18
d=30.80
w=6.40
+1.49%
|
325/55-18
d=32.07
w=7.04
+5.71%
|
325/60-18
d=33.35
w=7.68
+9.93%
|
325/65-18
d=34.63
w=8.32
+14.14%
|
325/70-18
d=35.91
w=8.96
+18.36%
|
325/75-18
d=37.19
w=9.60
+22.58%
|
325/80-18
d=38.47
w=10.24
+26.79%
|
325/85-18
d=39.75
w=10.88
+31.01%
|
| 335 |
335/25-18
d=24.59
w=3.30
-18.94%
|
335/30-18
d=25.91
w=3.96
-14.60%
|
335/35-18
d=27.23
w=4.62
-10.25%
|
335/40-18
d=28.55
w=5.28
-5.90%
|
335/45-18
d=29.87
w=5.94
-1.56%
|
335/50-18
d=31.19
w=6.59
+2.79%
|
335/55-18
d=32.51
w=7.25
+7.14%
|
335/60-18
d=33.83
w=7.91
+11.48%
|
335/65-18
d=35.15
w=8.57
+15.83%
|
335/70-18
d=36.46
w=9.23
+20.18%
|
335/75-18
d=37.78
w=9.89
+24.52%
|
335/80-18
d=39.10
w=10.55
+28.87%
|
335/85-18
d=40.42
w=11.21
+33.22%
|
|
Wheel Size 19
|
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|
Wheel Size 20
|
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|
Wheel Size 21
|
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The information on this page is intended to be helpful, but there is absolutely no guarantee of its accuracy, safety, or applicability for any particular use. The data is calculated mathematically, not taken from any official or recommended guide.
Please excercise a common sense, follow manufacturer and dealer recommendations, and check with other sources.
Tires are a safety equipment, don't take their selection lightly!