TOZOVR said:
Ok, we lift to maintain or improve axle articulation and fit larger tires....You want to limit articulation and turning raduius in order to fit the larger tires.
Just ask yourself if it's worth the trade off. For some, it is, for some, no.
Not so fast, Mate.
We lift to improve ground clearance. We also run larger tires to improve ground clearance. "Articulation" is a word that gets thrown around a lot recently, but I'm not certain how many people know what it means, or how it applies.
Let's start with answering the question: According to Ed Stevens' extensive research, you can run 31" tires
on stock rims with ZERO lift. Yes, they will rub the lower control arms at full steering lock -- and they will do the same thing even with 4" or 6" of lift.
Secondly, the combined experience of many XJ owners has shown that
without cutting sheet metal and flares and removing the inner fender liner, the largest tire you can run without hitting the inner liner at full suspension compression is a 235/75R15 (or equivalent). Doesn't matter how much lift you have, unless you extend the bump stops and/or start trimming, any tire larger than a 235 will rub. So the limitation on the compression side of "articulation" is the bodywork, not the lift. Of course, if you lift enough to run longer shocks, the shocks may stop compression travel before the tires hit the body -- but since shocks aren't designed to act as bump stops, that won't last very long.
I run 30s on a stock XJ off-road, and I've seen a stock XJ on 31s at my local Auto Zone (although I don't think that guy takes his off-road). You can run 31s with a budget boost. Whether or not that's anything close to an optimum setup depends on how you plan to use the vehicle. Personally, I think a budget boost and 30" tires is a well-balanced combination, and 31s with a 3" lift is a well-balanced combination.
BTW --
Ed's research was done on an early XJ. On the '97 and newer, the rear wheel arches/flares are different or the axle was moved slightly farther back in the opening, and 31s may hit the rear bottom corner of the flares. Running the tallest of the 4 available factory bump stops in the rear might be sufficient to alleviate this.