I want to run 33's possibly 35's. I have a 2k10 2dr w/ auto running 3.73 gears. I was going to upgrade to 4.56 gears. I recall something about not being able to run highway speeds if I do the swap. I just read a post about 5.13's running at 75mph with OD off. How can you run OD off on the highway? The poster said he was at 2600 rpms. Can someone help me understand all this please!

 

Hey man. If you do a search on gearing chart, or tire size gearing, you'll come up with all sorts of info. This subject has been hashed over lots of times.

A member named Jpop did a great chart and several explanations on the subject which will give you ammo for a wise decision.

 

If you are going up to 35" tires and you will lol
You have a 2dr auto..... Get 4.88 tops I wouldn't be thinking about 5.13's if you are.
I'd say 4.56 or 4.88
Good luck

 

^^^^^ what he said
And buy a superchip or other programmer to turn OD off and change ur shifting points and speedo. Helps alot.

 

Tire
Gear Ratio
Conversion;

Tire Vs Ratio
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

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 3438 3614 3727 3790 4023 4347 5051
32 2259 2334 2423 2546 2669 2805 2914 3112 3331 3501 3610 3672 3897 4211 4894
33 2191 2263 2349 2469 2588 2720 2826 3018 3230 3395 3501 3561 3779 4083 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 2202 2308 2426 2520 2692 2881 3028 3123 3176 3370 3642 4232
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 3013 3198 3455 4015
40 1807 1867 1938 2037 2135 2244 2331 2490 2664 2801 2888 2937 3118 3369 3915
44 1643 1698 1762 1851 1941 2040 2119 2263 2422 2545 2626 2670 2834 3063 3559

A Ratio of 3.73 with a 32 inch Tire has great fuel economy, but poor torque.
A Ratio of 4.11 with a 33 inch Tire is good as a daily Driver.
A Ratio of 5.29 with a 35 inch Tire has Great Torque, but poor fuel economy.

This is just a quick chart I threw together showing what Your RPM's will be at a certain Tire Size vs Gear Ratio, but as previously posted,
You can find a wealth of information on the net.

A simple formula for the correct gear ratio is this:

..........................New Tire Size x Old Gear Ratio
New Gear Ratio = ―――――――――――――――――
..................................Old Tire Size

Hope this helps some.

 

These two ratios are good for everyday driving with a 35 inch tire, but if
You plan to go off-road a better size would be to have 5.13 or 5.29.

 

Do you run freeway speeds and and tow much? Do you use your jeep for camping with lots of gear? Do you trail ride, Rock crawl, run San dunes or muddying?
Those are some questions to ask yourself besides what tire size.
My 2010 Jk Rubicon with a stock Ratio of 4.10 and 32's was not to bad for country cruising two lanes or basic trail riding.
When I threw on a set of 35 MTRS kevlars which are one of the lightest Mud terrain tire I no doubt had to drive with OD off at freeway speeds.
I think 5.13 would be a great gear ratio to goto with the Automatic and 35's

 

With 5.13's you would leave the overdrive off. Most than run with OD off do so with 4.10's or lesser gears running bigger tires. I would heat according to the tire you plan to run, which sounds like it will be 35's. 4.88 or 5.13 will be the way to go if that's the case

 

If you read the op he said he drove with OD off before the gear swap. I love my 5:13 Yukon gears and it is my DD it sees a mix of two lane, interstate, and city driving. As well as a weekend warrior. It sees 75 mph on a daily basis I avg 17 mpg.

 

Still a little confused. I only crawl up and down the local beach (no dunes). No off roading but highway speeds daily to and from work. I do tow but only for another year until my g/f buys a liberty for a DD and towing. I would like to be able to run highway speeds and have 35's for crawling the beach but still driving to work. Would 4.56's be ok for this? Why would I run with the O/D off? Wouldn't that make the rpm's higher? I do currently have a superchips tuner.