Not all knobbies are the same. On my klt 110 I have a both a duro knobby and cheng shin knobby on the back, both 22-11-8. The duro knobby is shorter and wider while the cheng shin is taller and narrower. I prefer the cheng shin as it offer more side wall flex for a smoother ride on the hard tail. Also if I pull a wheelie in snow my 110 will pull right every time due to the difference in size between the rears.
Just something to consider when looking at knobbies.
85 Kawasaki KLT 160
85 Kawasaki KLT 110
82 ATC 70
2000 Scrambler 500