ranchers are geared higher than the larger honda 4x4's
so there is a more noticeable power loss as you go taller in tire size, all the more so since they pout the newer Ranchers on the full sized frames,
Ranchers used to be on smaller lighter frames!
you have to be honest with yourself when asking about taller heavier tires, as you are only gaining a 1/2 inch of ground clearance for every inch of tire you add.
and then keep in mind NOT all tires measure true to size, including stock OEM tires
so, IMO< best idea might be measure how tall your current tires are now, how much power do you think you can live with loosing? and go from there!
and also don't forget that even LARGER atv's work this way too, bigger motors just help them turn larger tires SOME what, , honda atv's are about 26-28 hp, in there 420-500 line of atv's
How much HOP do you think you can loose and be happy with?
other brand atv's of like sized motors have about 38-50 hp, so they have a little more wiggle room to add taller tires?
BUT there CVT systems are not as efficient at getting HP to the ground, so they loose some HP that way right off the get go too ?
ain't no perfect made atv YET IMO