Tire Size and Gear Ratio Chart
Find your tire size in the left most column and the gear ratios are across the top.
The chart shows your estimated RPMs at 65 MPH assuming you are in 4th gear with a 1:1 ratio.
| Less Power / Better Gas Mileage | Balanced Power / Gas Mileage | More Power / Worse Gas Mileage |
| 3.07 | 3.21 | 3.31 | 3.42 | 3.55 | 3.73 | 3.91 | 4.11 | 4.27 | 4.56 | 4.88 | 5.13 | 5.29 | 5.38 | 5.71 | |
| 26" | 2580 | 2697 | 2782 | 2874 | 2983 | 3134 | 3286 | 3454 | 3588 | 3832 | 4101 | 4311 | 4445 | 4521 | 4798 |
| 27" | 2484 | 2598 | 2679 | 2768 | 2873 | 3018 | 3164 | 3326 | 3455 | 3690 | 3949 | 4151 | 4281 | 4354 | 4621 |
| 28" | 2396 | 2505 | 2583 | 2669 | 2770 | 2911 | 3051 | 3207 | 3332 | 3558 | 3808 | 4003 | 4128 | 4198 | 4456 |
| 29" | 2313 | 2418 | 2494 | 2577 | 2675 | 2810 | 2946 | 3097 | 3217 | 3436 | 3677 | 3865 | 3986 | 4053 | 4302 |
| 30" | 2236 | 2338 | 2411 | 2491 | 2585 | 2717 | 2848 | 2993 | 3110 | 3321 | 3554 | 3736 | 3853 | 3918 | 4159 |
| 31" | 2164 | 2262 | 2333 | 2410 | 2502 | 2629 | 2756 | 2897 | 3009 | 3214 | 3439 | 3616 | 3728 | 3792 | 4024 |
| 32" | 2096 | 2192 | 2260 | 2335 | 2424 | 2547 | 2670 | 2806 | 2915 | 3113 | 3332 | 3503 | 3612 | 3673 | 3899 |
| 33" | 2033 | 2125 | 2192 | 2264 | 2350 | 2470 | 2589 | 2721 | 2827 | 3019 | 3231 | 3396 | 3502 | 3562 | 3781 |
| 34" | 1973 | 2063 | 2127 | 2198 | 2281 | 2397 | 2513 | 2641 | 2744 | 2930 | 3136 | 3297 | 3399 | 3457 | 3669 |
| 35" | 1916 | 2004 | 2066 | 2135 | 2216 | 2328 | 2441 | 2566 | 2666 | 2847 | 3046 | 3202 | 3302 | 3358 | 3564 |
| 36" | 1863 | 1948 | 2009 | 2076 | 2155 | 2264 | 2373 | 2494 | 2592 | 2768 | 2962 | 3113 | 3211 | 3265 | 3465 |
| 37" | 1813 | 1896 | 1955 | 2020 | 2096 | 2203 | 2309 | 2427 | 2521 | 2693 | 2882 | 3029 | 3124 | 3177 | 3372 |
| 38" | 1765 | 1846 | 1903 | 1966 | 2041 | 2145 | 2248 | 2363 | 2455 | 2622 | 2806 | 2950 | 3042 | 3093 | 3283 |
| 39" | 1720 | 1798 | 1854 | 1916 | 1989 | 2090 | 2190 | 2303 | 2392 | 2555 | 2734 | 2874 | 2964 | 3014 | 3199 |
| 40" | 1677 | 1753 | 1808 | 1868 | 1939 | 2037 | 2136 | 2245 | 2332 | 2491 | 2666 | 2802 | 2890 | 2939 | 3119 |
| 41" | 1636 | 1711 | 1764 | 1823 | 1892 | 1988 | 2084 | 2190 | 2275 | 2430 | 2601 | 2734 | 2819 | 2867 | 3043 |
| 42" | 1597 | 1670 | 1722 | 1779 | 1847 | 1940 | 2034 | 2138 | 2221 | 2372 | 2539 | 2669 | 2752 | 2799 | 2970 |
| 43" | 1560 | 1631 | 1682 | 1738 | 1804 | 1895 | 1987 | 2088 | 2170 | 2317 | 2480 | 2607 | 2688 | 2734 | 2901 |
| 44" | 1524 | 1594 | 1644 | 1698 | 1763 | 1852 | 1942 | 2041 | 2120 | 2264 | 2423 | 2547 | 2627 | 2672 | 2835 |
Where did these numbers come from?