I am thinking of taking my 400ex through a mud run next year. However, I know that small tires hurt a bikes performance in going thorugh mud. I've got 25" swampfoxes that are on rims and they fit a 400ex. However, I realize that these 6 ply 25" tires will be harder on the clutch and may not be too good for the engine. So I played around with some calculations and concluded that (first number is front sprocket, 2nd is rear and final is tire size):

14:38:20 = 12:44:25

My question,

Is it possible to get a 12 tooth front sprocket for a 400ex?
Is it possible to get a 44 tooth rear sprocket for a 400ex?

The gearing with the 25" tires is actually lower (not by much). I enjoy the powerband with my 14 tooth front sprocket and would like to have the same feeling with 25" tires on and I realize with the extra weight of them, that I must gear a little bit lower.

Suggestions?

 

buy a 4x4

 

Man, modifying is part of the fun in ATVing.