How would I find out for sure what size tire I could run on my 2-door JK? My current setup is a Rough Country 4" Suspension lift with adjustable front LCA's and Smittybilt XRC Flat Style Fender Flares (non-armor). I would be changing wheels to ones probably with 4.5"-4.75" backspacing. I would like to run a 37" tire, however people are telling me that I can only run a 35" tire. Is there any way I could fit a 37, by trimming the pinch weld or something like that? What else would be necessary? I am also running Smittybilt SRC Side Armor.

 

you could run a 37 inch tire but the question you really should ask yourself is should you...if you wheel pretty nasty rocks then the investment in all the required upgrades might be worth it to you...this will all eventually include new axles driveshafts and a lot of steering reinforcement and work or switching to hydro steering...if you dont then 37s are not really needed and although you will still have to do quite a bit or axle reinforcement etc you may be happier running the 35s

 

All good points. I have a 4in lift and I can fit 37's although I dont want to go that big. 4.5 - 4.75 backspace is where you want to be. If I were building a jeep for tough off road and rocks, I would go with 37's but probably a 4.5 bs. The smaller bs will result in more strain on the axels since the wheels will be further away from each other. Either way, sleeves, gussets are mandetory from all that I have read here.

 

Sleeves and gussets are already on my list. Thank you. Also, gears, lockers, and axle shafts are on my list too.