In particular, a 21-inch, front wheel will turn more nimbly, and surmount off road obstacles much better than a 17-inch, front wheel. As related by others, the larger tires will also afford more ground clearance, and offer a much better selection of aggressive tire treads, at far more reasonable prices.
However, if you are only going to do light, off road riding, the supermoto will do an adequate job.
Spud
__________________
Spud
"Never argue with an idiot. He will drag you down to his level, and beat you with experience."
Mark Twain
2015 Zongshen ZS250GY-3 (RX3)
2006 Zongshen ZS200GY-2 (Sierra 200)
2005 Honda XR650L
2004 Honda CRF250X
1998 Kawasaki KDX220
Mods made to my Zongshen ZS200GY-2:
http://www.chinariders.net/showthread.php?t=6894