MJ Jeep Tech

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Posts : 38
Join date : 2018-04-07

Gearing and ratios

on Tue Apr 10, 2018 8:47 am
This is general information for Jeep drivers who want to regear there jeep for offroad, rock crawl, pulling or best highway mileage.

This is for general ref on all non over drive gear like 3rd for AW4, 4th gear on BA10/5, and 4th gear on AX15

This is ref for those in over drive for BA10/5 and AX15 in 5th gear

This is for the Auto AW4

As you can see by changing the tires on the Jeep it can impart your gearing big time.

So like My self I run 4.10's on my jeep with 31's with the manual 5 speed. If I wanted to say pull a very heavy load on the highway I could change my tires to the factory 205/75r15s 27.3". I would be in a power range in both 4th and 5th.

Now in theory I could put 35's on my jeep and get fuel mileage closer to factory when my truck came out. However when you add larger tires even with any gearing you need more power to turn those wheels, which can hit your mpg on any hills easily.

In fact with 31's on my jeep I get right around the same mpg as I did with factory tires 225/75r15 on the 3.08. I lost .75 mpg however it gained more power because of the high rpms.

So if your looking for something you can gear up and rock climb, but switch back to better driving around you can check the above numbers out. Of course most people when offroading and rock climbing want larger tires, not always those larger tires are needed. with 31's you can take on a lot more than you would think in a jeep.

Now for those who have the auto Aw4 the larger the tires you put and your offroading a larger transmission cooler is recommended. It is a strong mid level automatic, however you can easily over heat it, if you don't watch the temps.
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