If the trails you ride are rocky I would go with the 22" tires. I had them on my old 300ex. I also droped down to a 12 T front sprocket. For me it was a good combo. I have 20" razr tires on my 400ex and they are great but the 20 are to small for the local trails. Last weekend we did a 60 mile day trip down some rocky powerlines and when we got back my swingarm skid plate was about to fall off. At home I had to put the skid plate in a vise and bend it back into shape. Its a aftermarket skid plate. Iam getting a set of 22" for the trails and 20" for the sand pitts.