I have a sportsman 550 Eps le and my tires are wearing out I wanna go with some aggressive muffin tires like silverbacks or black mambas what the best size too do on a stock motor and stock clutch and stock ride height thanks

 

I think you answered your own question. If you are going to leave everything stock, I would go with stock tire size. If you are going to try and get an aggressive mud tire, they are usually heavier than stock so just stick with size you currently have and maybe you will,be able to get by without reclutching. Zillas are a good trail/mud tiree that many here have recommended and aren't really heavy......