max tyre dimensions are on a LR4 when you adopt the strictest criteria: NO MODS and NO RUBBING (or only very slight) in ACCESS HEIGHT
Hey Navi, someone here should know. It's been so long since I first went to 265/65-18 that I cannot remember. You also will have to specify if you're using just factory 19 or 20" wheels, and or if you're using 18" with or without spacers. The spacer/offset dramatically affects the tire you can use in full turning on access height.
My memory says that in order to use larger than 285/60-18 I had to have the 'frame horns' cut back. This is for when I changed up to 265/65-18. Both of those were on factory 18 which of course fit right onto an lr3.
For you to use 18 it would be simplest to have the compomotive unless the factory 18 works with a spacer of 25-30mm. I would not recommend one of these thicker spacers people claim to be screwing around with. Keep in mind 1" = 25.4mm so I'm talking about a 1"-1.25" roughly equivalent. H&R makes really nice ones in both those sizes.
So, if you were to compare the 18" 285/60 to 20" equivalent, for example, it would be a 285/50-20 which would in fact, fit fine on your LR4 in access, etc full turning functioning fine. I can say these sizes because I have used them first in Nitto Terra Grappler 18 and then Toyo Proxes ST in the 20". These were both on my 2006 lr3 which never had any modifications, only these tire changes.
It wasn't until the following year in my 2007 lr3 that I went crazy with the mods - well before these now well known mods had nicknames and before hardly anyone had tried them.
I think the tires above must be right around 31" which is why they fit while still looking more appropriately sized to the vehicle scale.