The tires are 225/75-16. The largest you can go before hitting the spring perch And these are 3" larger in diameter than the stock tires.

ETC just momentarily touches the brake, which is great in sand or mud or snow or shale, but when you're up against rocks it doesn't hold the spinning tire long enough for the torque to be transferred to the wheel with the grip. I think with low range they'd be able to climb and crawl a lot better.