So I currently have a stock '13 JKU with Ballistic Hostel 17x9 rims with 5.47 in backspace currently wrapped in 285/70/R17 Nitto trail grapplers. I understand I need a lift to put 35's on but am curious to know if 315/70/R17's would fit. I also have a Fabfours Lifetstyle bumper so no more front airdam to rub. Thanks for all the help and sorry I'm sure this has been gone over before but from the posts I read it seems that people only talk about the factory rims with aftermarket tires.

 

You'll need wheel spacers and you'll probably need to do some trimming......but it could be done....

 

the only difference btwn the 2 tires is how tall they are. IIRC a 285 is equivalent to a 32" tire & and 315 is close to a 34" tire. You ought to be alright (on pavement) at the very least do the pinch weld mod. Im sure someone else ought to chime in and elaborate some more.

 

What would I have to trim the front and rear fenders? As of right now the dirt my jeep sees is if I have to turn around in a dirt parking lot . The wife is 7 Months pregnant and gets sick if I drive over a speed bump to fast that is also why its not lifted she wouldn't be able to get in the jeep.

 

I wouldn't do it. You could with flat fenders and wheel spacers though.

I think a wide 33x12.5 looks nice and aggressive.

 

As long as your not articulating the suspension and keeping it on the pavement, you shouldn't have any problems clearing the fenders.

 

I won't lie I'm not really a fan of flat fenders. If I got a 2.5" lift and put those tires on would I need to regear or would I be fine with the 3.71 I have now?

 

From one of the many online metric tire converters:
285/70/R17 = 32.7x11.2
315/70/R17 = 34.4x12.4

Stock backspace is around 6.25". So your new rims with 5.50 only moves your tires out an additional 3/4". Most seem to agree that a 4.50 bS is a good place to be for a 35" tire.

You will probably want to move the tires further out of the wheel wells (new rims with less backspace, or wheel spacers), and add more room in the wheel wells (suspension lift, body lift, chopped flares, flat flares, taller bumpstops). You have options, it will depend on your preference and budget. Cheapest would be to just chop your flares (see writeup below), and then add taller bumpstops if needed, and add washers to the steer stops if needed. The faqs have some gearing info and some rpm charts, lift height vs tire height, all kinds of good info.

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

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

Decide on regearing after you drive it with the 35s. No one can tell you whether or not 'you' will want to spend that money. But there are dozens of other regearing threads to browse through to get some ideas.

 

You'd be totally fine with your gearing.

 

I have a 2.5" budget lift with 35" tires on my Sahara. Only slight rubbing in full turn in reverse going over a bump. Didn't regear and I'm fine. A little less power but I don't care. I drive slow so more people can get a chance to check out the jeep ;-). Gass mileage hurts a little. On the highway driving as economically as I can I got 20.5 mpg. Local start and stop is like 13 mpg. You could increase that a bit if you concentrate on driving slower. I'm glad I went with the 35s though. No regrets here.