should i go from 26 to 27 589's ?

you would gain 1/2" of GC, not much but its only one size bigger. i would trade if you need the 27" but if you dont really need them i would just stick with the 26" just because 27" are bigger and do weigh more and will cut down on some power. its up to you but if you dont really need them i would stay with the 26" just to have more power.
-Aaron

how does the rancher pull 26's im wonderin cause i got a rancher.

i used to have a rancher and i ran 27sx10x12 vamps but had alot of mods and it did good