I AM AT THIS TIME RUNNING 20-11-9 SHREDDERS ON THE BACK OF MY NEWLY REBUILT BANSHEE. THE PROBLEM IS WHEEL SPIN (LOTS OF IT). WHAT KIND OF TIRES IS EVERYONE RUNNING. WHAT'S GOOD AND WHAT'S BAD

 

wheel spin and banshees are just some thing that you can not stop but you might want to check out a amp-link

 

I run 22" bearclaws and even on hard pack dirt (very hard), from a standing start, I will spin wheels up to 4th...I mean I let off the throttle (flat out, of course)1st, screaming,2nd, still screaming in the high zone of the powerband, 3rd screaming, 4th and it goes from top of the powerband to way low (I usually have to go down 1-2 gears...hehe)
In the hard wet sand I usually ride on, I can't even pull a wheelie. But my riding pal has the same bearclaws and spins very little on his 400 scrambler.
If you ride in mud, bearclaws work great.