atv tires-gbc dirt devil xt?

[d11_thompson]

i have a big bear 400 w/ stock tires that measure rear 25-11-10, front 25-8-12. im looking at buying dd xt tires, but the lowest size for those tires are 26s. i want the xt's bc the lugs are bigger. would it hurt the performance of the atv if i had 26s on it. could i buy the xt's for the rear and dirt devil at's for the front. are there any better all terrain tires available for the terrain i ride. i ride on dirt roads, rocky trails, mud mostly, and are able to w/stand alot of abuse from the conditions.