91 pounds seems awfully heavy. What width and backspace? I've got 3.73's with truetracs front and rear. Maybe I should choose a size closer to 33".

 

Just ordered from Extreme terrain, some Mammoth-Boulder-silver 17x9's. Putting the Mastercraft MXT 35's on them.

 

Width is 8" and backspace is 4" ( -12mm offset )

BLUF Bottom Line Up Front: Get the 35's and re-gear down the road in you need to.

It's not as heavy as you'd imagine. According to the manufactures: 35x12.5x15 KM2 Tire is 60.8lbs (ea) & 15x8 Cragar Soft 8 is 30lbs (ea)
The KM2's are one of the lighter tires on the market but you can save about 8-10lbs per corner by running aluminum. The 33x12.5x15 KM2 is 59.6lbs each, not much of a difference and a lot of people who get 33's when considering 35's, regret their decision and wish they had just gotten 35's in the first place. (I know I did) I keep the Jeep lighter in other ways, mostly by running the factory bumpers, seldom do I use my hardtop and I'll be buying a lighter weight tire carrier soon enough. You could also fill the tires with helium, that might help

Your 3.73's should be fine for a while if you decide to run "35's". Keep in mind that very few tires are actually as tall as they say they are. My 35's measure out to 34" (off the Jeep) and my old 33's were actually 32's. Some 35's are even closer to 33". In regards to your gearing, it's a combination of the weight as well as the overall diameter of the tire that has an effect on your Jeep's power, and that's where the re-gearing comes into play, to regain the lost power.

I based my 4.10 gearing choice on the gear ratio chart that's floating around the inter webs. My JK is a '14 w/ manual (I was running 3.21's with 33" KM2's for a while before I switched) and with 4.10's and 34" tires I'm right in the middle of the "Green Zone" for recommended gear ratio per tire size.

 

Thanks for the input Flynlo!! Might have to try the helium route😆 So the 15's do not interfere with the brake components? I have a 2014 sport, auto.

 

15's with 3.75" backspacing won't rub. There's a possibility of rubbing with 4" of backspace though. Most JK's will accept the Cragar Soft 8's (w/ 4" BS) with no rubbing issues on the front calipers. It's not a big deal if they rub though. Use a grinder and remove a little material from the caliper and you're good to go. It's a very small amount that needs to be removed (if any needs to be removed) and there are ZERO issues with doing this to the calipers. With the amount of $$ I saved running a 15" wheel and tire combo, I can deal with a little grinding.

Not my picture but here's a visual:
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I'm still deployed so I don't know if my wheels will clear yet.

 

Discount Tire Direct listed a bunch of 15's that they guarantee will fit. Shouldn't be hard to find their thread with a quick search. One thing they noted was that steel wheels are much more likely to run into clearance issues than aluminum. (the title of the thread was something like ' 15" alloy vs 15" steel ' )


found it

https://www.jk-forum.com/forums/spon...wheels-120933/

 

did you try 4wd.com I just got a KO2 34x10.5-17 $257 shipped. Took 3 days to get it from when I ordered it.

I also scored a deal on 5 Saltas like new for $650, . Trying to decide if I want to mount my KO2's which are my DD tires or my Toyo 35's which are my offroad tires on them. almost too pretty to beat up lol.

 

Keep in mind the 15's that are guaranteed to fit have 3.75 minimum backspacing and vary in width as well (which effects the offset of the wheel, i.e. Two wheels of different widths, but same backspace will have different offsets). I've got a set of 33x10.5's mounted on 15's with 3.75" bs and I wasn't pleased with the "squatty" look it gave my JK. That's what pushed me into 35x12.5x15's but with 4" bs. Both wheels are 8" wide.

All of the tire width, backspace and offset nonsense will ultimately determine how far outside (or inside) of your fenders the tire will stick while mounted on the JK. If they stick out too far you might get in trouble with the law depending on your local fender laws.