Originally Posted by 
DiscoClax
				 
			
A Defo on 16s with std (nearly) 32" tyres has around 7" effective sidewall (the wheel lip is about 3/4" high, so you lose that). The tyre is sized/measured to the bead, not the visible rubber we generally think of as the "sidewall". On 18s you'd need a 34" tyre to match that sidewall height and that should be possible with slightly oversize tyres on the new one. RRC/D1/D2 ran 16s with 29s. That's actually less effective sidewall than a new Defo on 18s. Comparable to 19s on new Defo in fact. There's some context.
Barnsey at Birdsville brought in 1200 tyres just for last years Big Red Bash IIRC. Lots of those were 17s and 18s to cater for the LC brigade (and increasingly others, like some of us with later LR product). 16s are great, but 17s and 18s can be as good, or even better...