Hey - I have the stock 32" Goodyears on my Unlimited...if I were to bump them up to say a 33" (think that's about as high I could go w/out lifting) - would that effect gas consumption by much? Any ideas?

 

Some people are having rubbing issues with unlifted JK's runnings 33"s. And...its just an inch man, ain't worth it IMO. Leave it on 32"s, and if you aint happy with the tread pattern wear em out and get another set or sell em. Your MPG won't change drastically, but with 3:21's your already probably not getting the greatest of mileage. And something you may want to consider since your already running bigger tires(32's aren't tiny), find you a set of 4:11's or 4:10's (whatever i can't remember whats stock) on here when people are swapping their gears out for 4:88's and 5:13's (the people running 35"s and up).

My 2cents. Hope it helps.

 

On summer I have 33" tires, and on Winter I have 32"

The difference on gas consumming is very very small

 

Actually it's only a 1/2" lift, and 1" body spacers should take care of any problems if there are any. WOL has a write up on the spacers.

3:21 is far too low to go with larger tires, you lose a huge amount of torque at the wheel, you will almost always need to be in 4lo for off road anything. A Rubi transfer case could be a huge help here.

 

I'd bet you a weeks pay 3.21 gears will give ya better milage on the highway than 4.10 if everything else is equal. (long as u ain't in the mountains)

 

I went from the 32" goodyears to a set of 285/75R16's on my 2-door with 4.10's and lost about 1/2-1 mpg.

 

All depends on how aggressive the tread pattern is...your MPG will decrease by about 2mpg...

KSK

 

I think JP did something on this a long time ago and determined that there really was no difference in MPG between 32" and 33". If your unlifted id say stick with the 32's. The 33's you will get some rubbing on the wells and poor tread pattern will definitely ruin your mileage

 

WHICH tires you get will make this a non-issue, or cost you mpg...as some tires will have lower rolling resistance, and some will have higher rolling resistance.

A 33" tire is ~ 3% larger than a stock 32" tire...so, the difference is negligible as far as the diameter dimensions go.

Obviously, the 3.21 gets BETTER mpg than a 4.10 diff st, etc...as lower rpms ar what give you better mpg on the JK, down in the 1,800 k RPM range for cruising.

Lets say you are at 2,000 rpm on the 32's...and you swapped on 33's...your RPM would DROP to ~ 1,940 RPM (A whopping 60 RPM difference... )

This is hardly worth worrying about for mere 33's...

Of course, you might drive ~ 3% faster than normal...as if the speedometer SAYS you are going 65 mph...you will ACTUALLY be going about 67 mph....

...and your gas gauge will say you went ~ 300 miles on the 15 gallon fill up...but, you ACTUALLY drove ~ 309 miles.

This of course ALSO means your dash mpg meter will say you lost a little mpg...as you were going faster, and driving further, than it thought you were.

 

My pro comp 33's are actually 32" tall