bigbadron

It seems like most people run a 17" or 18" wheel to get bigger tires to fit. I think I want to stay with a 20" wheel, but would like to get a more aggressive AT tire. Does anyone know what the max size 20" tire will fit without major modification. Im not going to do any serious offroading, maybe some overlanding type stuff, so I dont need anything too extreme.

dgi

275/6020 is the size I keep hearing about.

Looks pretty tough here: https://www.clublexus.com/forums/lx-...-33-tires.html

Going to run the same size when its time to upgrade the tires on my 20s

Ratchey

Depends on your definition of "major". You can get 35s to fit fairly easily with some adjustments to the plastic and a body mount chop. 33's fit with just minor adjustments to the plastic.
The wheel diameter has little to do with bigger tire size other than tire size availability.