gearing help!!

[05400EXrydr]

i have an 05 400ex and im goin to put 18" tires on and im wondering what gearing i should use for mx?? Any pics of 05 or 06 ex's would be nice too..my aim is Hquadkid47 or my email is htrx400EXrydr@hotmail.com Thanks

[SHADETREE101]

15/38 is stock, with the smaller tire it will rev out faster. if you are running a tight track then 14,38 should do the job. longer track 15/38. just gonna have to play with it a little to find where you want the rpm's to be. each track will run different.