soccer882017-09-19 05:22:24

GEAR RATIO & TIRE SIZE CHART

Considering making modifications to your Jeep? Whether it is changing an axle or going with different tires this chart is helpful in finding the right Tire Size to Gear Ratio that you need to achieve the optimal performance for your particular application.

Also, when making altering your factory gear ratio or wheel size your speedometer and odometer may read incorrect. Make the necessary changes to your speedo by replacing your Jeep Speedometer Gear .

A basic method to calculate is to mutiply .12 by your tire diameter. (.12 X 38" = 4.56)

The below table can be used to get a rough idea on gear ratios. The colors represent ideal RPM's at highway speeds (65). These calculations are assuming a manual transmission with a 1:1 ratio. If you drive an automatic your RPMs will be slightly higher, and the opposite is true if you have overdrive (your RPMs will be slightly lower).

Highway cruising and best fuel economy stay towards the yellow (2600 rpm)
Around town daily driving is color coded green (2800 rpm)
Better towing power or just more 4-low power use the ratios near the red (3100 rpm).

 

FIND YOUR GEAR RATIO

TIRE SIZE

 

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

6.17

7.17

27"

2677 2766 2872 3017 3163 3325 3454 3689 3947 4150 4279 4352 4619 4991 5800

28"

2582 2668 2769 2909 3050 3206 3331 3557 3806 4001 4126 4196 4454 4813 5593

29"

2493 2576 2674 2809 2945 3095 3216 3434 3675 3863 3984 4052 4300 4647 5400

30"

2410 2490 2584 2715 2846 2992 3109 3320 3553 3735 3851 3917 4157 4492 5220

31"

2332 2409 2501 2628 2755 2896 3008 3213 3838 3614 3727 3790 4023 4347 5051

32"

2259 2334 2423 2546 2696 2805 2914 3112 3331 3501 3610 3672 3897 4211 4894

33"

2191 2263 2349 2469 2588 2720 2826 3018 3230 3395 3501 3561 3779 4093 4745

34"

2126 2197 2280 2396 2512 2640 2743 2929 3135 3295 3398 3456 3668 3963 4606

35"

2065 2134 2215 2328 2440 2565 2664 2845 3045 3201 3301 3357 3563 3850 4474

36"

2008 2075 2154 2263 2372 2493 2590 2766 2961 3112 3209 3264 3464 3743 4350

37"

1954 2019 2095 2203 2308 2426 2520 2692 2881 3028 3123 3176 3370 3642 4243

38"

1902 1966 2040 2144 2247 2362 2454 2621 2805 2948 3040 3092 3282 3546 4121

39"

1854 1915 1988 2089 2190 2302 2391 2554 2733 2873 2962
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