I upgraded my Unlimited X tires to 265 75 16's (almost 32") and it lost some low end, especially on hills. I have a 6 speed manual transmission also.

My question is, if I re-gear, should I go with 4.10's or jump on up to 4.88's? I want some better low end power, but don't want to kill my gas mileage any more than I have to.

 

4.88's will be a little much for those tires, if you were running 35-37's that would be a different story......but I wouldnt pay 1000-1200 dollars to re-gear to 4.10's especially since 4.10's come as an option on some and standard on others. I would either do some motor mods, or jump up in tire size and then re-gear.

 

Do 4.10s if you're pretty sure you're not going to increase the tire size for awhile.

 

4.88 Automatic
4.10 6 speed

IMO

 

Not with tires that small! Auto or stick, you shouldnt need more than 410's for those tires.

 

Say what you want... My opinion just differs. I have the 4.10 with stock 18's and the tires that are more like 31.5's than 32's, and I personally would like just a few more rpm's out of my very low revving gears. 1500rpm at 60 is quite low. Especially round town with the auto. I'm sure I'd be happier with the 4.10 if I had more gear choices. But I did make my decission according to how I like to wheel. I like the way the I don't have to take my foot off the gas to switch gears in a criticle moment.

 

You need to decide if you are ever going to a larger tire.

If not I like 4.27 - a big bump in power but still good mileage.
If yes, how large? Lots of people have opinions here. Based on other vehicles I have owned (dont have my JK yet) 33s = 4.56, 35s = 4.88. These tend to be a good compromise between power/fuel efficiency.

In any case I would definitely recommend AGAINST 4.88 with 32" tires. That is just WAY too steep.
JMHO

 

ditto... my auto w/ 4.10's seems pretty sluggish now w/ 32" tires compared to the orig 29". I also lost overdrive on anything but very flat terrain . But the 4.10 should be enough for the stick I would think.

 

get bigger tires and go 4.88 now rather than taking a hit in the long run after you are sick of the 32s

 

Says you...

I'd say you'd want 4.56s, but since that not an option just go 4.88s. A little low is better than not enough, plus the tire bug will hit and you'll want larger tires.