Kojack

Think i will be ok using 285/75/17 on my sport with 3.21s? I will have it set to the proper tire size using the programmer etc. I figure it would be like my old 3.8L with 285s and 3.73s. I have alot more power now to spin them.

rob_engineer

So that tire is around 34" diameter. Yes, it will feel like you have a bit less power. There have been debates on here for at least 8 yrs now regarding people going to 35's with 3.21. Most people hate the power loss while some say it's ok. Those with manual trans say 6th gear becomes useless.

jadmt

I never had a problem in my 2013 sport with 3.21 auto with 33's. I know lots said it would be gutless but it was fine. The only thing I did not care for was in hilly highway driving it would hunt to stay in the proper gear when traveling at 70mph or so. lots of up and down shifting but that was the only negative.

lowendrider

I have 285 70 17s with the 3.8 , 6spd. Yes, 6th hasn't been used in a couple years and I WILL regear before going any larger.

jkrubcon

I'm running 295's on stock Rubi wheels with 321's. Some power loss feel at the stop light until I got a Flashpaq f5. I've got it tuned for a pretty good seat of the pants/mileage ratio. I can still get 19-21 highway and a OK snap at the stoplight.

thatwhitejk

I currently am running 35x12.5R17 KO2's on my 14 JK with stock 3.21 gears. A little sluggish off the start but its not too bad at highway speeds. A flashCal tuner to adjust for the tire change and to fix the speedometer and it's a little better..
Gears in the future but not in the budget at the moment!

Kojack

How is it at around 60mph/100kph? does it hunt gears alot? that's what I am worried about most. My 3.8 was adequte with 33's my 3.6 has way more power so I figure if I use a lighter 35, I could get away with it if he does not constantly hunt for top gear on the highway

jadmt

it is not the weight of the tire nearly as much as the diameter that makes it hunt. larger diameter is what lowers your rpm at any given speed in a particular gear not weight. I have owned 4 wranglers with 3.6's and ran all different sizes of tires. unless you are a total flatlander 33's is most I would go with 3.21's. look at some 255/80-17 or 295/70-17 tires as they will be 33. I would not do 34's 285/75-17 with 3.21's. and I have run plenty of 285/75-17's. (Toyo and Cooper)

Kojack

I have pretty well commited to 285/70/17 C range BFG AT. I think it's the perfect tire for what I want to do. Another quick question, I am going to be running the teraflex leveling kit again, and I want to add their bumpstop kit to my rig as well. It's for the 2.5" lift. If I leave the spacers off the axles for that kit, it should work decent with the 2" lift?