bobbjeep

Hi
I have a 2010 2 doors jk with a 2.5inch teraflex lift kit
I want to put maxtrek mudtrac 35 12.5 17 tires on it. How about all the mechanics; transmission,diff, axle and all that stuff, is this stock jeep can handle with these?
And the maxtrek tire, what'd you think?
I mostly drive on the road, but eventually will goes into the trail.
Then, what about the offset I will need, because I'll get some rims for these tire. I would like to have the best offset without going over the flares, and no hitching when turning the wheels. Or if there is any legal ways or tricks to modify my actual stock flares.
Thanks!!

shawnphi1

U got the 3.8 engine I'm assuming and maybe 3.21or 3.73 gears so the 35" tires will be a little sluggish imo until u regear the axles. Rims will need a 4.5" backspacing at minimum to help with no rubbing.

Trail Jeeps

With the 3.8 gears are pretty much a requirement for 35s. Just plan on them as part of your build, at least that's our motto. I would regear to 4.88. It'll allow to wring out every pony that 3.8 has, it'll also save your transmission. The 42RLE 4 speed is marginally equipped to handle the stock Jeep, let alone 35s. Depending on what gears your Jeep has you can step up on tire size, but I wouldn't recommend a 35" tire. If you have factory 3.21 gears a 285/70/17 is about as tall as you would want to go. If you have factory 3.73s, you can swing something slightly larger. I like a 285/75/17 on a JK with a 2.5" lift. You can grab a power programmer and set your shift points and use it to squeeze an extra couple of ponies out of the engine.

If you do choose to step into 35s, a 17x9 with a 4.5" backspace is money on a JK. I would also choose a tire brand that runs slightly smaller than advertised with a rounded shoulder. A BFG All Terrain is a great example of a smallish 35 that works great on a JK.

silverbullet88

I can tell you that 35's with the 3.8 and even 4.10 gears sucks. Around town and flat freeway (with no wind) is not bad. ANY gradient of hill on the freeway is terrible unless you build your speed a lot before the hill.

I have not regeared but I added a transmission cooler to keep the temps down with it having to work a little bit harder. Honestly it locks the torque converter most of the time, so hills are the only struggle. It never hunts for gears unless I'm on the freeway and going up hill.

My 35's are KO2's which run a bit small

Wandell

What is everyone's opinion on going to 5.13 gears for a 3.8, auto, 35 inch tire combo on a JKU? I'm aware of the strength issue with those gears in a Dana 30. I'm talking strictly performance opinions.

Rednroll

I have 35x12.5 (315/70/R17's) BFG KO2's mounted on 17x9 wheels with 4.5in back spacing. I don't have any turn rub issues, but my tires do stick out about 1in beyond my Sahara fender flares. That is easy to see, in that dirt/mud is thrown up on the sides of my JKU which didn't happen before going to the wider tires.

I'm running 3.73 gears with the 3.8L and auto trans. My advise is to leave your gearing alone and then make a decision after you've had some time to evaluate the performance for yourself. If you believe all the internet advise on re-gearing you'll start to believe the JK will not even move with 35's and 3.73 or smaller gears and realize it's really an over exaggeration in many cases. After I got my 35's on, I was scratching my head saying to myself, "This isn't really as bad as it was described." I'm sure re-gearing will be more necessary if you live in mountain road areas, so take that into consideration if that is your situation. That is not the case for me. I'm sure there's a day that will come that I will want to re-gear to 4.56 or 4.88's. That is in the plans when I decide to add front/rear LSDs. There's really no rush for re-gearing until your budget feels comfortable to re-gear. Re-gearing isn't cheap, so it's easier said then done to just say to throw in some new gears.

Get yourself a tuner with a performance tune and evaluate for yourself and decide, before jumping into re-gearing.

Rednroll

For offroad only use, 5.13 sounds great. You'll get a bunch of low speed, low-end torque performance. For highway use, it doesn't sound like much fun. If your Jeep is a DD, weekend warrior like most of us, you probably want to aim more for re-gearing to 4.56 or 4.88. If you have a chance, find someone with either 4.56 or 4.88 and test drive it for yourself on the highway and decide what you prefer. Then keep in mind while driving 4.88 gears that those RPMs will be even higher at highway speeds with 5.13 gears.

nthinuf

https://www.jk-forum.com/forums/modi...bie-has-18617/

https://www.jk-forum.com/forums/modi...-lifts-288269/

https://www.jk-forum.com/forums/jk-w...s-video-80145/

There are a few thousand previous threads on gears to read through for opinions. But start with opening the Faq's, you will find some nice charts that will show where the rpm will be with 35's based on various ratios.

There are also a bunch of previous threads talking about mods to the front axle housing. Gussets, sleeves, truss, skids, etc. Read through some of those just so you know what the options are, then you can decide if you want any of it.

4.5" backspace is the typical recommendation for 35x12.50's. This moves the tires out enough so that they don't rub the frame/control arms/whatever.

Legal? Can't comment on the laws where you are, but down here different states or cities have their own thoughts/laws about fenders and tire coverage. Check yours before chopping the flares or moving the tires out.

Wandell

Well, the gearing charts I've seen say I'd be turning 2380 RPM at 70 MPH in overdrive with a 35 inch tall tire and 5.13's, which doesn't sound too bad.

catahoula

Maybe even look at a 295/70/17.