just started riding less than a year ago. couldn't decide btwn dirt bike or street so went with dual sport - now been doing a lot of dirt riding and the stock tires suck - unfortunately, cannot find good knobby tires for the bike - stock is 100/90-18 rear and 70/100-21 front - figured i'd check around to see if anyone else has this bike and what they use - do i need to use the above sizes or can i use a size up - and if so, what are good tires to use - again just learning, mostly going on ohv trails