Be looked all over this thread and can't really find an answer. What are the biggest tires that will fit onto stock wheels of a 2014 JKU? I want to get 33" but the width of the confuses me. Also the metric conversion doesn't make sense to me. I don't know which tires are 33" (285, 295, etc). I'm looking at BFG ko2 285/70/17s but not sure if they'll fit the wheels. I can't afford new wheels right now.
I know it's a dumb question with likely a simple answer so I appreciate any response!

 

So a 285/70/17 converts to a 33x11.22x17 tire. That will easily fit on an OEM rim.

This link converts tire sizes.

Tire Size Converter | Metric to Inch Tire Size Calculator

The KO2 is an excellent tire. We run this exact size on my wife's jeep with no spacers and no rubbing. Great tire.

 

285/75/17 toyo at2 fit stock rims and measure in at 34" tall

 

My understanding of the metric conversion is as follows for the 285/70/17s:
the 285 = 28.5 cm in tire width. Since there are 2.54 cm/inch, the division results in 11.22 inches of tire width.
The sidewall height is 70% of the tire width = 7.854 ".
The tire height = 2 xs the sidewall height + 17 " of wheel diameter = 32.7 inches. And by the time the tire warms up, it should be at least 33 inches.
But my KO2s on 17" wheels cold really only measure ~31 inches on the tape. They probably get to about 32 when warm, but I can't say that I have measured them warm.
The width and the bossy tread is cosmetically attractive enough, even w/o the "true" 33" height, and the mileage is probably a bit better as well. I haven't done any rock crawling, but I have the security of very well built sidewalls if I do, albeit stiffer than other tires, so the ride will be harder until you air down.

 

The size quoted by the manufacturer is dismounted size. The actual height (as measured from the ground) will vary based on the width of the rim it's mounted to and the weight of the vehicle.

 

I'm kind of in a similar position as sleepinggas14, 2015 JK 2d Sport with 17 Alloy wheels, looking at the same BFG tire. I happen to live very close to 4Wheel Parts and they told me they would not install a 33" tire without a lift kit, as they would not put a customer in a situation where the tire may not fit. Guessing this could be a sales tactic, but I just want to ask the Forum for their thoughts. I know the tire will fit the rim, but will the tire cause me any issues since it's roughly 1" in taller and 1" wider?

I have never really planned on lifting the Jeep, as this is a daily driver, and most of my off-roading is fire roads in and out of Yosemite Valley in NoCal, and a few trail heads in SoCal. That said, with the BFG tires (285X70X17), what factors should I consider in a new wheel? How much back spacing should I consider?

Last question, the current tire is a 255X75X17 Goodyear Wrangler, looks more like a highway tread than an All Terrain tread. How will the bigger BFG tire affect my current driving (comfort, traction, mileage, noise)?

Thanks for any feedback!

 

I was in your shoes about 3 months ago. My take from all the advice on this forum is that 33s on stock Jeep is fine w/o a lift. I put a 2 inch budget boost on the front just to level it out. I have only taken mine on some wash board roads out to the Upper Owen River since then and have had no problems, but I can see lots of clearance above the tire so I think the JK forum advice is solid about adequate space above the tires for yours and my type of terrain. Also even if you got a true 33 inches from the BFG KO2s, you would only add 1 inch against the wheel well clearance, not 2". And really the height is less than the nominal 33" anyway.

I can't speak to back spacing since I changed wheels coincident w/ the tires, so you will have some homework to do or others can advise. I have had no problems with rub and since your are adding only 30 mm total, split on both sides, it really adds only about 5/8" to the inner width; unlikely to be significant.

As for driveabiltiy of the KO2s , i have not noted any increased road noise. I have not compared mileage yet. Comfort is probably better than before, but perhaps only because I aired down to 35 psi and will go down to 30 on hwy as advised by at least 2 sources. And probably to 18 if I get on any serious rock trails.

Several opinions on the JK Forum strongly recommended these tires as did my retailer. My hesitation was the stiff sidewall since I was seeking a softer ride; so there are other softer tires out there and JK forum has a comparison elsewhere on this site, but security of the strong (but stiffer) sidewall sold me on these. So far so good after a mere 3 months of very intermittent driving on vacations.

Good luck. Hopefully others with longer experience will chime in.

 

Fishtailer, many thanks for a well thought out response. One last question, "did you change out your stock shocks?"

The 2-d Sport shocks are not very good. Was thinking of Bilstein 5100's.

 

Rancho is having a buy 3, get 1 free sale right now and they've got a 90 ride guarantee. I've got the 5000x shocks and they're alright but you may want to try something a little higher end if you dislike the factory ride. Rancho offers an adjustable shock, the 9000x.

 

I'm sure that was a sales scheme. My local tire shop has the 285's and said they'd put them on a stock jeep no problem. I plan on adding 1.5" spacers if they rub