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Jeep Wrangler JK Gear Ratios

JK Gear Ratio's

Part #:

This started by me trying to find a good gear ratio chart for my JK. After searching and talking to the people I came upon the understanding that nothing seemed to match. I found different opinions on where the power was, how it was calculated, and even preceived. The charts I found ranged from very good to bad. Some had inaccurate final gear ratios for the transmissions, some used different speeds, some had numbers that didn't match what they said they were calculating, some used 1 as their final gear ratio.. So I sat down built a chart based on the acutal gear ratio's for the final gear on the JK's, pulled the good charts and put down a somewhat ballpark idea of where you power bad would be. I calculated the speeds for the highway and trying to use overdrive or you highest gear on the Manuals. We don't normally drive down the highway in a gear lower because we love to pay for gas. My charts are not the gospel on gear ratio's, but will give you a decent idea. From experience and friends it seems that 4.56 is a good manual final axle ratio, and 5.38 (07-11) or 5.13 (12-up) for the Automatics on 35's, 37's and up require a ratio bump in the same direction. I haven't seen much over 5.38's without using custom axles under the Jeep.

Color Chart
  Performance Gear Set
  Acceptable Gear Set
  Minimum Gear Set

 

Jeep Wrangler JK Gear Ratio Chart, 3.8 Liter Engine, Automatic Transmission (07-11)
1st 2.84
2nd 1.57
3rd 1
4th 0.69
Reverse 2.21
Speed MPH 70                  
Transmission Ratio 0.69                  
 
  Axle Ratio

Tire Size

3.21 3.73 4.1 4.56 4.88 5.13 5.38 5.86 6.17 6.5 7.17
29 1797 2088 2295 2553 2732 2872 3012 3281 3454 3639 4014
30 1737 2019 2219 2468 2641 2776 2912 3171 3339 3518 3880
31 1681 1953 2147 2388 2556 2687 2818 3069 3231 3404 3755
32 1629 1892 2080 2314 2476 2603 2730 2973 3130 3298 3638
33 1579 1835 2017 2243 2401 2524 2647 2883 3036 3198 3527
34 1533 1781 1958 2177 2330 2450 2569 2798 2946 3104 3424
35 1489 1730 1902 2115 2264 2380 2496 2718 2862 3015 3326
36 1448 1682 1849 2056 2201 2314 2426 2643 2783 2931 3234
37 1409 1637 1799 2001 2141 2251 2361 2571 2707 2852 3146
38 1371 1594 1752 1948 2085 2192 2299 2504 2636 2777 3063
39 1336 1553 1707 1898 2031 2136 2240 2439 2569 2706 2985
40 1303 1514 1664 1851 1981 2082 2184 2378 2504 2638 2910
41 1271 1477 1624 1806 1932 2031 2130 2320 2443 2574 2839
42 1241 1442 1585 1763 1886 1983 2080 2265 2385 2513 2772
43 1212 1408 1548 1722 1843 1937 2031 2213 2330 2454 2707
44 1184 1376 1513 1683 1801 1893 1985 2162 2277 2398 2646

 

Jeep Wrangler JK Gear Ratio Chart, 3.8 Liter Engine, Manual Transmission (07-11)
1st 4.46
2nd 2.61
3rd 1.72
4th 1.25
5th 1
6th 0.797
Reverse 4.06
Speed MPH 70                  
Transmission Ratio 0.797                  
 
  Axle Ratio

Tire Size

3.21 3.73 4.1 4.56 4.88 5.13 5.38 5.86 6.17 6.5 7.17
29 2076 2412 2651 2949 3156 3317 3479 3789 3990 4203 4637
30 2007 2332 2563 2850 3050 3207 3363 3663 3857 4063 4482
31 1942 2256 2480 2759 2952 3103 3255 3545 3732 3932 4337
32 1881 2186 2403 2672 2860 3006 3153 3434 3616 3809 4202
33 1824 2120 2330 2591 2773 2915 3057 3330 3506 3694 4075
34 1771 2057 2261 2515 2692 2829 2967 3232 3403 3585 3955
35 1720 1999 2197 2443 2615 2749 2883 3140 3306 3483 3842
36 1672 1943 2136 2375 2542 2672 2803 3053 3214 3386 3735
37 1627 1891 2078 2311 2473 2600 2727 2970 3127 3294 3634
38 1584 1841 2023 2250 2408 2532 2655 2892 3045 3208 3538
39 1544 1794 1971 2193 2347 2467 2587 2818 2967 3125 3448
40 1505 1749 1922 2138 2288 2405 2522 2747 2893 3047 3361
41 1468 1706 1875 2086 2232 2346 2461 2680 2822 2973 3279
42 1433 1665 1831 2036 2179 2291 2402 2616 2755 2902 3201
43 1400 1627 1788 1989 2128 2237 2346 2556 2691 2835 3127
44 1368 1590 1747 1943 2080 2186 2293 2498 2630 2770 3056

 

Jeep Wrangler JK Gear Ratio Chart, 3.6 Liter Engine, Automatic Transmission (12-up)
1st 3.59
2nd 2.19
3rd 1.41
4th 1
5th 0.83
Reverse 3.16
Speed MPH 70                  
Transmission Ratio 0.83                  
 
  Axle Ratio

Tire Size

3.21 3.73 4.1 4.56 4.88 5.13 5.38 5.86 6.17 6.5 7.17
29 2162 2512 2761 3071 3286 3455 3623 3946 4155 4377 4828
30 2090 2428 2669 2968 3177 3340 3502 3815 4017 4231 4668
31 2022 2350 2583 2873 3074 3232 3389 3692 3887 4095 4517
32 1959 2276 2502 2783 2978 3131 3283 3576 3766 3967 4376
33 1900 2207 2426 2699 2888 3036 3184 3468 3651 3847 4243
34 1844 2142 2355 2619 2803 2947 3090 3366 3544 3734 4118
35 1791 2081 2288 2544 2723 2862 3002 3270 3443 3627 4001
36 1741 2023 2224 2474 2647 2783 2919 3179 3347 3526 3890
37 1694 1969 2164 2407 2576 2708 2840 3093 3257 3431 3784
38 1650 1917 2107 2344 2508 2636 2765 3012 3171 3341 3685
39 1607 1868 2053 2283 2444 2569 2694 2934 3090 3255 3590
40 1567 1821 2002 2226 2383 2505 2627 2861 3012 3174 3501
41 1529 1777 1953 2172 2324 2444 2563 2791 2939 3096 3415
42 1493 1734 1906 2120 2269 2385 2502 2725 2869 3022 3334
43 1458 1694 1862 2071 2216 2330 2443 2661 2802 2952 3256
44 1425 1656 1820 2024 2166 2277 2388 2601 2739 2885 3182

 

Jeep Wrangler JK Gear Ratio Chart, 3.6 Liter Engine, Manual Transmission (12-up)
1st 4.46
2nd 2.61
3rd 1.72
4th 1.25
5th 1
6th 0.797
Reverse 4.06
Speed MPH 70                  
Transmission Ratio 0.797                  
 
  Axle Ratio

Tire Size

3.21 3.73 4.1 4.56 4.88 5.13 5.38 5.86 6.17 6.5 7.17
29 2076 2412 2651 2949 3156 3317 3479 3789 3990 4203 4637
30 2007 2332 2563 2850 3050 3207 3363 3663 3857 4063 4482
31 1942 2256 2480 2759 2952 3103 3255 3545 3732 3932 4337
32 1881 2186 2403 2672 2860 3006 3153 3434 3616 3809 4202
33 1824 2120 2330 2591 2773 2915 3057 3330 3506 3694 4075
34 1771 2057 2261 2515 2692 2829 2967 3232 3403 3585 3955
35 1720 1999 2197 2443 2615 2749 2883 3140 3306 3483 3842
36 1672 1943 2136 2375 2542 2672 2803 3053 3214 3386 3735
37 1627 1891 2078 2311 2473 2600 2727 2970 3127 3294 3634
38 1584 1841 2023 2250 2408 2532 2655 2892 3045 3208 3538
39 1544 1794 1971 2193 2347 2467 2587 2818 2967 3125 3448
40 1505 1749 1922 2138 2288 2405 2522 2747 2893 3047 3361
41 1468 1706 1875 2086 2232 2346 2461 2680 2822 2973 3279
42 1433 1665 1831 2036 2179 2291 2402 2616 2755 2902 3201
43 1400 1627 1788 1989 2128 2237 2346 2556 2691 2835 3127
44 1368 1590 1747 1943 2080 2186 2293 2498 2630 2770 3056

Ratio Charts
Ratio Calculator

 

 

  N-m Ft. Lbs. In. Lbs.
       
       

This page last updated: 17-Oct-2012

Content and Design © 2002-present WanderingTrail,  Ronald Seegert
Common Sense and Safety should always be observed when working on your vehicle or doing modifications. Jackstands, wheel blocks, disconnecting the battery are a few of the basic safety precautions that should be used and may not be mentioned in the write ups on this site. You are responsible for your own installation, these write ups are a helpful guideline and should not be taken as an official installation instruction. My write up may be different from the kits currently out there, so alwasy double check the manufacturers installation instructions when installing anything. I try to keep the site up to date with changes that have occured as I discover them, but may not have the latest unless someone lets me know. If you feel that an install is above your capabilities after reading my write ups, I recommend getting together with a club and getting some help. Only a few times have I needed to employe some actual help from a shop to get something done. Usually welding or A/C work. While I have spent many years working on mechanical systems, I am not an expert, nor do I pretend to be one. I hope these write ups have been useful to you.
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