DigitalCK

Okay here we go... talking about a 2017 JKU Sport. 100% stock except for using rubicon rails and been rocking some rubicon wheels with BFG MT KM's. Bumpers/fenders/suspension are stock.

I'm due for new tires, so splurging on new wheels as well. Might do more, but not sure. Currently not taking it offroad, we have a 2020 rubicon for that.

I'm currently looking at getting the Pro Comp 69's in 17x9 (-6 offset, 4.75 backspace). But not sure what I should do for tires.

It seems like there's a lot of "don't go bigger than 32 or 33 or you'll rub". Is that only offroad? Will daily driving be fine otherwise?

Could I theoretically go to 35's? Would I need to swap fenders to give more room or is it something else that would rub?

Would I need to regear as well if I go past a certain size?

Jay2013jk

HI, Have run 285/70R17 Falken Wildpeak AT3s on the 7069s with a 3/4in spacer in front.. no issues - very limited off road.. Also do run same tire on American Racing ATX's and had some rear tire rub on the fender off road articulated. Have Rubi rock rails on both no issues. Would not go 35's w/out 2 or 2.5 in lift.

nthinuf

The answers to all of your questions are based on opinion and specific build. Read enough of the older threads asking those same questions, and you will see opinions - stated as fact - that re-enforce both sides of each debate. Can you run 35's with no lift? Of course. Will you rub driving onroad-only? Yes. Can you bumpstop or add steerstops to limit the rubbing? Yes. Will it be enough? No idea, it is situation based. Is that loss of movement worth it to you? Again, no idea. Same with trimming. How much are you willing to take from the skid or bumpers or where ever you rub?

Remember that no two builds will be the same. A 35x12.50 from one mfg might measure out to 34.5 x 12.75", while the same size from another mfg might measure out to 33.5 x 11.5. Which tire is more likely to rub in this scenario? How many factors other than measured tire size are involved? Quite a few...

My example - 4 inches of measured lift height, trimmed flares, 4.5" backspace and 35's that measured out to a pathetic 33.5". A front tire would rub every single time I turned through two particular intersections in town. Even though the speed was low, the dip on one road and the steeper incline on another was just big enough and the tires were turned just far enough to cause tire contact when the suspension compressed. I started avoiding those two intersections, problem solved...

resharp001

I don't see you mention what your current gearing/transmission is and nobody has asked yet. If you are running 3.21 and are considering 35s, the cost of regears in Dallas is coming down. My buddy owns one of the larger shops in town and they're regearing JK's at $1200 these days, and I've seen him advertise sales for $1k. The FADs on the JLs require a tiny bit more hassle and they are doing those for $1500, the ole JK standard. I think that fact drove the cost of regears down on the JKs a bit. Just throwing that out there for budgeting purposes if it's relevant.

I started out on 35s and 3.73. It wasn't ideal but bearable. If you had 3.21 any larger tire starts to become a bit much.

DigitalCK

Thanks for the replies so far. A few replies to @resharp001 and @nthinuf

* I'm currently running BFG MT TA KM (old!) 255/75/17's. This appears to be (at new size) around 32.1" tall and 10" wide on stock 17x9 JK Rubicon wheels
* I'm considering running BFG AT TA KO2 285/75/17's (33.9" tall and 11.3" wide"),315/70/17 (34.4" tall and 12.7" wide), or 33x12.50x17 (32.5" tall and 12.5" wide).
* My preference above is the 315/70/17, followed by 285/75/17
* These would be running on the 17x9's mentioned in my first post.
* My current gearing is 3.73 (purchased the towing package originally and this was in it)
* I am considering fenders that allow more room (metal tubular like metalcloak style likely) but not immediately
* I am considering bumpers that allow more room, too (XRC front) but not immediately
* I am not planning on a lift, but have been considering the "leveling kit" which gives just a little more room it seems - could do this at the same time

Any feedback on the tire sizes above with the given info?

resharp001

From a gearing perspective, I think any of those tires would be liveable with 3.73 gears. Probably not worth the additional gearing expense for a pavement only rig.

nthinuf

As I touched on above, there is 'mfg spec' - what you listed - and there is actual measured size, which might not be quite as big as you expected. BFG's are known to run on the small side, some others are better known for running more true to size. Doesn't hurt to try a search for some reviews and see what others have reported.

Regardless, it seems that you really want 35's, so my opinion is to go ahead and get them now and figure out how to run them. (rather than kicking yourself and losing money selling them and buying a bigger set next year). Nothing wrong with a cheap budget boost to gain a little more clearance, go for it. You could also consider chopping your stock flares, which could easily get you by until you upgrade to nice metal ones. (I'm too cheap to buy nice flares, so have been running chopped flares for 10 years now. I have broken a few on trees/rocks/F-250's, and just find another cheap/free set of take-offs someone wants to get out of the garage. Another half hour chopping the new set and I'm good to go.) Other clearancing options will depend on where you are rubbing. Taller bumpstops can work, but would not be my first choice. Same with adding washers to the steer stops. It may work, but I would rather not. Anyway, you have options, just try to look at the bigger picture before you decide and see what makes sense.