That is the size I'm gonna run on my 400. I friend had some 20x11x10 S.T.U. Sand Skate II's on his 250R and they worked great. My tire setup will be 20x10x10 Skat Trak Edge on Douglas Ultimate Billet center wheels and Skat Trak Mowhawk fronts on Douglas Ultimate Billet center wheels. I highly recommend Skat Trak tires. Best paddles I've ever used, well worth the extra money.
http://www.geocities.com/jcrmotorsports
'00 400EX, '97 RM250
http://www.geocities.com/jcrmotorsports
'00 400EX, '97 RM250