ed...one more thing that has been an on-doing debate with no "science experiment" to back it up: if you carry the OEM spare and get a flat, you may be f*cked if you have to use it. Having one tire smaller than the other 3 may cause the LR3 to have a TC/DSC hissy-fit!
I always meant to test it out, but never did. Wound up buying a 5th 275/65R18 tire and put it on an X5 rim for a spare! Got 'em both for $100!!! I have an HSE but run the 18s when offroad with MT/Rs mounted. ...so I just throw the aforementioned used BFG long-trail tire on an X5 rim in the back when I go! No need to fit it underneath for one day.
...but long story short no one knows what will happen with 3 31.5" (or bigger) tires and one 30" (OEM sized) tire.
that certainly makes sense, but isn't there a way to turn the dsc off?