I have a'91 jeep wrangler 4.0 , my gear ratio is 3.07, I am putting

36 inches super swuampers ...? What gear ratio should  I change to??

I will not be doing any 4- wheeling. my jeep is mainly my comute car.

Thank you for your advice...

First off...the thought of putting anything over a 31" tire on a rig that will never be off the pavement boggles my mind.  

That being said, if you want to spend the money, I wouldn't go anything less than 4.88 gear ratio.  Also, if you are still running your stock diff & axles, you have to think of the strain trying to turn 36"'s.

Thank you so much for taking the time to answer my question.

Basically the only reason i bought 36's was just going for the looks.

I did asked around and even the people who put in the lift told me that

it would be fine for the road, the speed will increase , the speedometer will be off and  the gas millage even will be. If I was not going to 4-wheel I would be "fine". I already bought the tires, they will  be here in

week. I have 30 days to try the tires. If i am not happy I ca exchage them for a lesser zise. I think I will have to spend the money for gears.

thank you again i would appreciate any extra input.... 

http://jeephorizons.com/tech/rpmchart.html

the above link is everything you need to determine this.  4.10's are a good choice for a cumute car.  I can also say 4.56 might keep your top speed too low.

Good luck

Thank you so much for your reply.  

I'd agree that road use won't out right kill the axles, but you will certainly feel the pinch as most of your driveline components will wear out much faster, and the gas mileage will go in the crapper.

I will never understand lifting a 4x4, and throwing on big tires, just so it can pound pavement, BUT if I were going for that look Swampers would be not on that list.. they are a fairly soft tire, with a very agressive tread.  they will wear horribly, and horribly fast, not to mention howl like mad.  maybe a BFG all terrain 36" would be more road friendly and still get the look. (and thousands more miles)

sorry- no idea on what gear to use.

I agree with the  33-36 BFG's AT. I got three years off lite weekend wheelin and a whole lot more daily driving. While my friend threw on 33 swampers and got just over a year with the same driving conditions. And about that hum of the tires. I'll just say at top speed it sounded like a single prop plane coming down the road.  

If you really have to have the 36-inch tires you'll want 4.88 gears. But wait to do the gear change untill you are sure you are keeping the 36s. Running 4.88 gears and 33s would be unfun at higher speeds. With your 4.0L I would run 4.10s with 31s, 4.56s with 33s, and 4.88 for 35-36s. A 4.88 gear set is as low as you can go with those axles.

John