How big of a tire can I go with an 88 4.0 auto with stock 3.55 gearing?

 

your stock tire. hence the "stock" gearing of 3.55 for a "stock" tire.

anything bigger and you will have decreased power, trans will work harder and start to get warmer. save for the tire size you want and the CORRECT gearing for said tires

 

I've been running 31's, that's about the max I want to go. Its fine as a DD, it will upshift out of OD on the highway if I'm going up a slight grade.

 

not entirely true. my stock tire size was 26in with 3.55 gears. im running 32's now with the same 3.55 gears and i have no decreased power and trans stays just fine. to the OP you will be fine with up to 32's i would say but after that i would suggest regearing.

 

no way in hell. your mpg's have gone down and your tranny is hotter.

 

actually i get great mpg's if you look at a gearing chart my gears are helping my mpg. i get currently about 16mpg with 5in and 32's and about 22 on the highway. only way my mpg would go down would be with like 4.56 gears and 32's since that is set up for a lot of torque and power

 

Go as BIG as you want.

 

That's a ridiculous statement. So if he wants to go to a 30 inch tire, he should waste his money and go to, what? 3.73s? He'll be regearing in another 3 years to go to 33's.

OP, nothing bigger then 32's. It my dog a little, but nothing crazy. I'm currently running 31's on 3.55s, and the only different I see is in the braking.

 

i have 3.55s with 30's drives fine

 

You are mentioning MPG's going down... well, that is quite obvious, friend. put bigger tires on, your MPGs always go down. Why? well, say you had a stock tires size of 30...
30Xpi=94.2, this is the circumference of that tire.
Now say you went to a 38...
38Xpi=119.32

now, for each rotation of the tire, the 30 is traveling 94.2 inches while the 38 is traveling 119.32 inches. You with me still?

Ok, now, as you get a bigger tire, you are covering more ground per rotation, but, from the center to one point on the circumference of the tire is a farther distance, and requires more work to turn it. The difference here? 4 inches (bear in mind, the radius is half the diameter, and the 2 diameters are 30 and 38.) Now, if you have a yo-yo with 15 inches of string, and a yo-yo with 19 inches of string, and you spin it, the shorter stringed yo-yo requires less effort to keep going in a circle. So yes, there is more effort needed in spinning a bigger tire, and I am almost certain all jeep people understand there is a tradeoff, a little gas mileage to be able to travel in more places. And as for the tranny getting hot? I think you need to study a little more on how they work. A little extra tire isn't going to make any notable difference, i mean, maybe a fraction of a degree, but certainly not any doomsday prophesy you seem to be spewing.

So, with all due respect (and this means Exactly what it is supposed to, that I am about to say something rude, and trying to pretend to sound polite) If you don't actually KNOW what you are talking about, please refrain from commenting, as someone new will be worried about the words coming from someone who doesn't know what they are talking about, and this could lead to a dissappointed Jeep owner. You wouldn't want that, would ya? Read a little more, learn your jeep a little more, and other than that, don't post unless you actually have something worth hile to say, and have a nice day.



****As to the OP, you can pretty much put whatever tires would fit under your rig (assuming your rig is stock) that won't cause rubbing. There isn't enough room under there to put anything to terribly big under it, so you will be fine. And for the record, both me and my buddy had wranglers, and I went up to 38's and he to 37's, and NEVER had a problem. Stock gears. My buddy ended up changing his because he wanted more low end power for off roading, but that was an OPTION, not a NEEDED change. I hope this helps you out, OP, and listen to the people with real experience. Good Luck.

 

i just looked at xjbeedlocks post history and hes a sarcastic pric about 99% of the time

never listen to people whose entire life goal is to make inexperienced people feel like crap for asking questions

 

before you post something about someone decides yourself you might want to learn how to spell first.

 

wheres the dooms day I'm spewing. I said your MPG's will go down, just like you said and you have mathematical equations to prove what i said. I said your tranny will get hotter for working more, just like you said through your mathematical equations.

again wheres the dooms day I'm spewing?

 

He was just saying you made it would like your tranny would undergo a thermonuclear reaction if you go bigger tires on stock gears.

 

I run 32's on 3.55's and three of my buddies have run 33's on 3.55's. One has run them for 4 years and we havent had any issues. Did know one guy that had 35's on stock gears for 3 months but his mpg and get up were terrible.