Gear Ratios - Jeepz.com

Gear Ratios

Terry Mason
Published by TerryMason
11-13-2005

Gear Ratios

Gear Ratio Calculator

This simple Gear Ratio calculator assumes that you're running around 65 MPH

All you need to do is look at your tire size on the left, then find out how many RPMs your engine is at when you are doing 65 MPH, and that will give you your Gear Ratio. the blue blocks are good gas mileage, green it a good medium and red is for more power.

#1 (permalink)

By TerryMason on 01-26-2008, 09:26 AM

Jeep Gear Ratio Calculator

	Gear Ratio This chart will tell you the rpm needed to reach 65 mph
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
	27	2677	2766	2872	3017	3163	3325	3454	3689	3947	4150	4279	4352	4619
	28	2582	2668	2769	2909	3050	3206	3331	3557	3806	4001	4126	4196	4454
	29	2493	2576	2674	2809	2945	3095	3216	3434	3675	3863	3984	4052	4300
	30	2410	2490	2584	2715	2846	2992	3109	3320	3553	3735	3851	3917	4157
	31	2332	2409	2501	2628	2755	2896	3008	3213	3838	3614	3727	3790	4023
	32	2259	2334	2423	2546	2696	2805	2914	3112	3331	3501	3610	3672	3897
	33	2191	2263	2349	2469	2588	2720	2826	3018	3230	3395	3501	3561	3779
	34	2126	2197	2280	2396	2512	2640	2743	2929	3135	3295	3398	3456	3668
	35	2065	2134	2215	2328	2440	2565	2664	2845	3045	3201	3301	3357	3563
	36	2008	2075	2154	2263	2372	2493	2590	2766	2961	3112	3209	3264	3464
	37	1954	2019	2095	2203	2308	2426	2520	2692	2881	3028	3123	3176	3370
	38	1902	1966	2040	2144	2247	2362	2454	2621	2805	2948	3040	3092	3282
	39	1854	1915	1988	2089	2190	2302	2391	2554	2733	2873	2962	3013	3198
	40	1807	1867	1938	2037	2135	2244	2331	2490	2664	2801	2888	2937	3118
	41	1763	1822	1891	1987	2083	2189	2275	2429	2599	2733	2818	2866	3042
	42	1721	1778	1846	1940	2033	2137	2220	2371	2538	2668	2751	2798	2969
	43	1681	1737	1803	1894	1986	2087	2169	2316	2479	2606	2687	2733	2900
	44	1643	1698	1762	1851	1941	2040	2119	2263	2422	2546	2626	2670	2834

Blue = 2600 RPM

Better Mileage

Green = 2800 RPM
Around factory

Red = 3100
RPM
Good Power

Last edited by TerryMason; 03-05-2008 at 06:29 AM..

#2 (permalink)

By kawstxf15 on 07-19-2009, 10:19 PM

Re: Jeep Gear Ratio Calculator

Terry,

Should I assume I am driving in 5th gear to reach 65mph, please confirm the gear.

Last edited by TerryMason; 07-20-2009 at 06:27 AM..

#3 (permalink)

By captjanes on 08-30-2009, 10:10 PM

Re: Gear Ratios

i have a four cyl jeep and i put a 4 inch lift and 35 inch tires my jeep cant go fast enough to put her in 5th gear i drive aeround in 3rd and 4th gear and she can only do 100 km/h.. i want my jeep to go faster and have more power for in the mud and in sand.. can u plz tell me what to do with my jeep

#4 (permalink)

By Bounty__Hunter on 08-30-2009, 10:59 PM

Re: Gear Ratios

Quote:

Originally Posted by captjanes

Regear the axles to 4.88, that is as low as you can go with the stock axles, even though lower is better.

#5 (permalink)

By Bounty__Hunter on 08-30-2009, 11:03 PM

Re: Jeep Gear Ratio Calculator

Quote:

Originally Posted by kawstxf15

Terry,

Should I assume I am driving in 5th gear to reach 65mph, please confirm the gear.

I think it would be 4th, or 1:1 transmission ratio.

Regardless of transmission gear, find your stock gear ratio on top and move down until your at your stock tire size. Record that RPM. Then move to your current or desired tire size and move across the chart to the right until you find an RPM similar to the previous number. Move up and find the suggested gear ratio for the new tire size.

#6 (permalink)

By captjanes on 08-30-2009, 11:21 PM

Re: Gear Ratios

so what ur saying is that to get more speed and power out of my jeep i has to change the gears in the front and rear differentials axels? someone told me that i had to change a gear in the transmission is this true or do i just have to regear the axels? and can u tell me how about going to regear the axles.. where can i order gears to? thanks in advanced

#7 (permalink)

By Team Twisted Off Road on 01-22-2010, 06:40 AM

Re: Gear Ratios

Hello to terry mason.. I have been looking into 4:88 gears and have found that your chart is wrong 31" tires and 4:88 gears you have 3838 and it should be 3438 thanks team twisted off road.

#8 (permalink)

By Bounty__Hunter on 01-22-2010, 03:11 PM

Re: Gear Ratios

Quote:

Originally Posted by Team Twisted Off Road

Hello to terry mason.. I have been looking into 4:88 gears and have found that your chart is wrong 31" tires and 4:88 gears you have 3838 and it should be 3438 thanks team twisted off road.

It's all relative to what gear the transmission is in, and isn't really necessary information to use the chart.

To simply use the chart, find the given RPM for stock tire size and stock gear ratio. Then go the line of the tire you want to run, and move over until you find a similar RPM, or slightly higher, that is your recommended gear ratio.

#9 (permalink)

By Team Twisted Off Road on 01-23-2010, 05:29 PM

Re: Gear Ratios

Quote:

Originally Posted by bounty__hunter

it's all relative to what gear the transmission is in, and isn't really necessary information to use the chart.

To simply use the chart, find the given rpm for stock tire size and stock gear ratio. Then go the line of the tire you want to run, and move over until you find a similar rpm, or slightly higher, that is your recommended gear ratio.